Device for a system for building up a body in layers

专利摘要:
Device (1) for a system for building up a layer (K) of a body (K) from a radiation-curable substance (S), with a trough (2) having a trough (3) for receiving the radiation-curable substance (S) a construction platform (4) arranged above the tub floor (2) and height-adjustable in relation to the tub floor (2), and with a sensor (5) interacting with the tub floor (2), the tub floor (2) being at least partially flexible, wherein a chamber (6) is provided, the chamber (6) being delimited by an underside of the trough bottom (2), the sensor (5) being set up to detect a change in volume of the chamber (6) and to provide a sensor signal a sign of the volume change can be determined.
公开号:AT521717A1
申请号:T50838/2018
申请日:2018-10-01
公开日:2020-04-15
发明作者:
申请人:Sirona Dental Systems Gmbh；Dentsply Sirona Inc；
IPC主号:

专利说明:

The invention relates to a device for a system for the layer-by-layer construction of a body from a radiation-curable substance, with a trough having a trough base for receiving the radiation-curable substance, with a construction platform arranged above the trough base and height-adjustable in relation to the trough base, and with a sensor interacting with the trough bottom, the trough bottom being at least partially flexible.
The invention also relates to a method for building up a layer of a body from a radiation-curable substance, which is received in a tub which has a tub floor, and for each layer of the body to be formed, a height-adjustable construction platform with respect to the tub floor the tub floor is moved, which defines a distance between the construction platform or the last formed layer of the body to the tub floor to the extent of at least the thickness of the layer of the body to be formed, the radiation-curable substance for forming the layer of the body selectively by means of a radiation source by irradiation is cured, and the height-adjustable construction platform with the adhered, hardened layer of the body is moved away from a rest position of the tub floor in order to create space for the formation of a next layer between the hardened layer of the body and the tub floor, wherein the tub b ode is at least partially flexible and at least one process parameter is detected by a sensor interacting with the tub floor.
Devices and methods for the layer-by-layer construction of a three-dimensional body from a radiation-curable substance are also known under the terms 3D printing, additive manufacturing or rapid prototyping. The cross-sectional information of the substance to be hardened in layers by electromagnetic radiation, for example a photo resin, is generally created by a mask projection method or by a laser source. In generative manufacturing machines, which enable a continuous printing process, for example, the cross-section or the
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Layers, mostly pixel-controlled DLP (Digital Light Processing), MEMS (Microelectromechanical Systems), LC (liquid crystal) displays, LED displays or controllable lasers. The exposure creates a solid layer from the liquid, photosensitive substance. This layer adheres to a carrier and is removed or removed from a reference surface by lifting the carrier. In subsequent manufacturing steps, the hardened layer detached from the reference surface acts as a carrier. In this way, a three-dimensional body is successively drawn or formed from the photosensitive substance.
The curable substance is generally received in a tub with a radiation-permeable and at least partially flexible tub bottom. With the flexible trough base, the pulling forces generated during the separation process of the hardened layer from the trough bottom can be minimized in order to avoid that excessive pulling forces damage the body to be generated or separate from the building platform.
A known problem is the lack of information as to when the generated body has detached itself from the tub floor. Accordingly, an empirical value is usually used, which can additionally be varied depending on the radiation intensity and geometry of the hardened partial layer.
EP 2 173 538 B2 relates to a device for producing a three-dimensional component by solidifying a solidifiable material, with a radiation source, a component carrier with a platform supporting the component, a container for holding solidifiable material, a flexible film or a foil in the construction area of the Component, a displacement device for displacing the component carrier, a sensor and a control unit connected to the sensor for controlling the displacement device and the radiation source. The sensor is arranged to sense or measure a pressure or tension on a flexible film or sheet in the construction area. The sensor allows real-time monitoring
3/98 process critical factors. The measured value is output to the control unit in order to adapt the movement or the movement speed of the component carrier by means of the displacement device.
Although the known devices are designed to detect and control individual process parameters, there is a need for improved devices, in particular for more extensive detection and control of process parameters.
It is an object of the invention to provide a device and a method as stated at the outset, which (s) enable the acquisition and control of process parameters in a manner which is as simple and reliable as possible and thus a rapid production of layers built up in layers with the least possible rejection. In addition, error states in the manufacturing process should be reliably detected or avoided.
For this purpose, the invention provides a device as defined in claim 1 and a method as defined in claim 15. Advantageous embodiments and further developments are specified in the dependent claims.
According to the invention, it is provided that a chamber is provided, the chamber being delimited by an underside of the trough bottom, the sensor being set up to detect a change in volume of the chamber and to provide a sensor signal from which a sign of the change in volume can be determined.
The device, which is at least part of a system for the layer-by-layer construction of a body from a radiation-curable substance, has a trough with an at least partially flexible trough base for receiving the radiation-curable substance. For this purpose, the tub is designed to be liquid-tight to an extent which prevents the curable substance (the curable material) from flowing out unintentionally through the tub. The curable substance can, for example, by electromagnetic radiation,
4/98 can be curable in particular by light, such as visible light or UV (ultraviolet) light. In particular, the curable substance can be a resin. The curable substance can have a viscosity, for example, in the range between that of water and that of a pulpy or pasty substance. A building platform is arranged above the tub floor and is height-adjustable in relation to the tub floor. The construction platform, which is expediently designed as a flat plate, serves as a platform on which the body is built up in layers by irradiation of individual layers of the curable substance in regions. With the height adjustment of the construction platform, the distance between the construction platform and the tub floor is adjusted, i.e. the height of the construction platform is defined as the distance to the (floored or unloaded, essentially horizontal) tub floor. The device also has a sensor which interacts with the trough base in order to be able to detect deflections of the flexible trough base from a loaded or unloaded rest position. For this purpose, a chamber is provided which is delimited by an underside of the tub floor. The trough bottom is thus part of a chamber housing of the chamber, which is provided below the trough (i.e. on a side of the trough bottom opposite during operation of the hardenable substance) and in which chamber a compressible or essentially uncompressible medium is accommodated. Accordingly, part of the chamber, for example a wall of the chamber, is formed by the trough bottom. The chamber is therefore essentially a closed or partially closed container, the interior of which is partially delimited by the trough bottom. The sensor interacting with the trough base can be accommodated in the chamber or in the cavity of a body connected to the chamber, for example in the cavity of a hose connected to the chamber and interacting with the interior of the chamber. Such a body connected to the chamber can in particular be understood as part of the chamber.
The sensor is set up to detect a change in volume of the chamber and to provide a sensor signal from which a sign of the change in volume can be determined. The sensor is thus in particular designed at least for the detection of whether
5/98 the volume of the chamber increases or decreases, and, depending on this, outputs a sensor signal with at least two different signal values or signal forms, a signal value / signal form in the event of an increase in the volume of the chamber and another signal value / signal form in the event of a reduction the volume of the chamber. The different signal values / signal forms can then be assigned a positive and a negative sign of the change in volume of the chamber. The changes in volume depend on the position or the deflection of the tub floor. The sensor can also be designed for the detection of a constant volume of the chamber in order in this case to output a sensor signal with a third signal value or a third signal form. The sign of the volume change does not have to be determinable from a single signal value of the sensor signal. For example, the sensor signal can also enable the sign of the volume change to be determined on the basis of at least two signal values of the sensor signal acquired at different times.
The sensor signal mentioned above can in principle also be provided by a sensor which can determine the absolute volume of the chamber. I.e. such sensors are included in the figure. On the one hand, a change in volume can be determined from the absolute value of the volume by repeated measurement and a corresponding sensor signal can be provided (even if the determination is not actually carried out, the change in volume would still be ascertainable); on the other hand, a single absolute value can also be compared, for example, with a predefined reference value or with a threshold value in order to provide a signal from which a change in volume or at least its sign can be determined (e.g. change above / below reference value or above / below threshold value).
The invention is not limited to sensor signals from which only the sign of a volume change can be determined. Likewise, the invention is not limited to sensor signals that include the sign of a volume change. Rather, sensor signals are also included, for example
6/98 also (i.e. in addition to the sign) or even exclusively specify or include an absolute value of a volume change, because a corresponding sign can already be determined from the absolute value. For example, if the rate of change is above a predefined threshold value, it can be assumed that the volume is reduced after the last layer of the body removed from the tub floor. The predefined threshold value can be determined at least approximately from the speed of movement of the construction platform and the area of the last layer produced, because these parameters determine the absolute value of the expected maximum increase in volume (i.e. the maximum positive change in volume).
In addition, the invention is not limited to a single sensor. For example, several sensors of the same or different types can be provided, which are set up to detect a change in volume of the chamber and to provide a sensor signal from which a sign of the change in volume can be determined. It is not necessary for the change in volume or its sign to be determined on the basis of the sensor signal of each individual sensor independently of the other sensors and their sensor signals. Rather, it is sufficient if the sensor signals of the individual sensors are taken into account along with other parameters and sensor signals when determining the volume change or its sign; i.e. Determinability within the meaning of the present disclosure already exists for the individual sensor signals when the change in volume or only its sign is ultimately determined from a plurality of sensor signals.
By providing the sensor for detecting a change in volume of the chamber and thus for detecting the process-related change in position of the pan floor, the device can be used to detect a large number of process parameters which are associated with the change in position of the pan floor. In particular, only partial, i.e. local changes in the position of the tub floor can be detected with the sensor. If, therefore, a position of the tub floor is referred to below,
7/98, this does not necessarily mean an even or flat arrangement of the tub floor. Rather, the position, the position, or the deflection of the trough base is also defined for a trough base that is curved or is deflected differently over its surface extension.
If reference is made to the terms height, horizontal, vertical, top, bottom, above or below in the description, these terms or other location or directional indications are to be understood in the use position of the device.
According to a preferred embodiment of the device, the sensor is set up to quantitatively record a measurement variable which is directly or indirectly proportional to the volume of the chamber or to the change in volume and to make it available as a sensor signal. The volume or the change in volume of the chamber is thus detected by detection of the directly or indirectly proportional measured variable. The sensor is designed to detect this measured variable and to output a sensor signal representing the value of the measured variable.
It is particularly favorable if the sensor has a pressure sensor set up to detect a pressure and / or a pressure change corresponding to the change in volume of a compressible medium accommodated in the chamber and / or a sensor to detect a change in the amount of substance corresponding to the change in volume of the amount of substance enclosed in the chamber is in the chamber accommodated fluid (ie a gas or a liquid) arranged and arranged flow sensor, the sensor being set up to provide a detected pressure and / or a detected change in pressure and / or a detected change in the quantity of substance as a measurement variable and sensor signal. The pressure, the change in pressure and the change in the amount of substance in the chamber are directly or indirectly proportional to the volume of the chamber or the change in volume. If the sensor is a pressure sensor, a pressure and / or a change in pressure in the chamber, in particular a compressible medium accommodated in the chamber, can thus be detected. As a pressure sensor, the sensor thus detects a change in volume
8/98 tion of the chamber about the pressure or a change in pressure in the chamber. The pressure, pressure changes, volume and volume changes depend on the position or the deflection of the tub floor. In order to ensure reliable pressure detection by the sensor, the chamber is closed in this case, at least during the deflection of the trough base from a rest position and measurement of the pressure or the change in pressure, and is essentially sealed for the compressible medium. The closed chamber does not have to be completely sealed, i.e. it can have slight leaks as long as the function of the device, in particular a pressure detection largely correct for the manufacturing process of at least one body to be produced, is maintained. I.e. the pressure chamber can be designed in such a way that a slow / sluggish pressure equalization with the environment can take place if process-related pressure gradients can nevertheless be detected. The sensor can also be a flow sensor that is set up and arranged to detect a change in the amount of substance corresponding to the change in volume of the amount of substance enclosed in the chamber of a fluid received in the chamber. In this case, the sensor designed as a flow sensor detects a change in volume of the chamber via the change in the amount of fluid in the chamber. The change in the amount of substance, the volume and the volume changes depend on the position or the deflection of the tub floor. For this purpose, the chamber has at least one opening acting as an inlet and / or outlet for the fluid, i.e. a fluid exchange can take place between the interior of the chamber and the exterior of the chamber or a fluid reservoir provided for this purpose. The flow sensor is arranged in or at least near the opening in order to be able to detect the fluid flow through the opening, into the chamber or out of the chamber. In the case of a plurality of openings, a plurality of flow sensors can be provided, each of which is assigned to an opening, so that a flow sensor is preferably assigned to each opening. A volume change can then be determined from a balance sheet of all determined changes in the quantity of substance. The accuracy of the detection of the fluid flow is not necessarily high. It may be sufficient that the mo
9/98 mental direction of the fluid flow, i.e. whether it is directed into the chamber in the event of an increase in volume or out of the chamber in the event of a decrease in volume. However, the flow sensor can also be designed to output the detected fluid flow with greater accuracy. Compared to pressure detection, the detection of volume changes via the change in the amount of substance in the fluid enclosed in the chamber has the advantage that, due to the opening in the chamber, pressure equalization can take place automatically between the inside and the outside of the chamber and a deformation of the base of the tub by changing the outside air pressure ( Weather, installation location of the device) can be avoided. In addition, the requirements for the tightness of the chamber are lower and thus the susceptibility to failure of the tub is reduced. The pressure sensor is set up to provide the detected pressure or the detected pressure change or at least the detected sign of the pressure change as a sensor signal or output signal. Accordingly, the flow sensor is set up to provide the detected change in the amount of substance or at least the detected sign of the change in amount of substance as a sensor signal or output signal. Within the scope of the present disclosure, several different sensors can also be used in parallel in order to combine the advantages of the different measurement methods and to achieve greater flexibility with regard to the use of the chamber. For example, a pressure sensor can be used in conjunction with several flow sensors.
According to a preferred embodiment of the device, the sensor can be connected to a processing unit which is set up to process the sensor signal provided by the sensor. For this purpose, the processing unit can have a microprocessor or a microcontroller. In addition, the processing unit can be connected to a data memory, which contains data and / or program commands for processing a volume change detected by the sensor or a measurement variable proportional to it. To operate the processing unit by an operator, the processing unit can be connected to an input / output device, for example a touchscreen. By providing the processing unit / 98 processing unit, actions required for the production of the 3D body can be carried out automatically. In contrast, these actions would have to be carried out manually by an operator without the processing unit, for which purpose the sensor would be connected at least to a display unit for displaying the detected volume change or a measurement variable proportional to it or a sign of the volume change determined from one or more measurement variables.
In order to be able to control the device appropriately, it is advantageous if the sensor is connected via the processing unit to a drive unit for the height-adjustable construction platform and / or to a control unit for a radiation source, which is provided for irradiating the radiation-curable substance. and the processing unit is set up to control the drive unit for the height-adjustable construction platform and / or the control unit for the radiation source as a function of the sensor signal provided by the sensor. Values of the pressure, the change in pressure or the change in the amount of substance and / or a determined sign of a change in volume can thus be transmitted by the sensor, preferably in real time, to the processing unit and processed therein. If the processing unit is connected to the drive unit for the height-adjustable construction platform and is designed to control the drive unit, the height adjustment of the construction platform can be carried out by the processing unit depending on the detected pressure, the pressure change or the change in the amount of substance or a determined sign of a volume change in the chamber. The drive unit makes it possible to move the construction platform and thus the body to be manufactured at least to the tub floor and away from it. The drive unit is preferably designed, the construction platform or the lowest, i.e. bring the last layer of the body to the bottom of the tub. The drive unit can have an electric motor, for example a stepper motor, which is connected to the construction platform. In particular, the electric motor can engage a height-adjustable rod, the rod being connected to the construction platform. If the processing unit with the control unit for radiation
11/98 source and is designed to control the control unit, the radiation-curable substance can be irradiated by the processing unit depending on the detected pressure, the pressure change or the change in the amount of substance or a determined sign of a volume change in the chamber. The control unit is preferably designed for the radiation source and thus also the processing unit for controlling the radiation intensity and / or the radiation duration. The radiation source can be a light source, in particular a source for visible light or UV light. The radiation intensity and / or the radiation duration generally have an influence on the adhesive force of the cured layer produced with this radiation intensity and / or radiation duration on the previously cured layer or on the building platform.
Furthermore, it is favorable if the chamber has at least one adjustable pressure source for setting a static pressure in the chamber and / or an adjustable heating device for setting a temperature in the chamber and / or an adjustable process material source for the adjustable supply of a process medium for at least local manipulation of the solidification process the radiation curable substance is connected to the chamber and / or an air flow source to generate an air flow in the chamber. The rest position of the tub floor can be adjusted by setting the resting pressure in the chamber. However, the resting pressure can also be changed during the manufacturing process of the body, for example in order to promote detachment of the last manufactured layer of the body from the tub floor by applying a vacuum or overpressure in the chamber. An overpressure in the chamber would, for example, promote detachment if the overpressure occurs intermittently with or without a combination with a Z movement (i.e. lifting or lowering the carrier). An overpressure in a self-supporting, stretched film would also increase the tension of the film and thus additionally tension and thus stiffen the tub base formed by the film. When using a semi-permeable film, the overpressure can be used particularly advantageously, since when an inhibitor such as oxygen is used it prevents adhesion or the formation of an inert intermediate
12/98 layer shift for the next shift cycle enabled or at least influenced. The overpressure favors the diffusion of the inhibitor through the semi-permeable film. Adjusting the temperature in the chamber can change the viscosity or other process-relevant properties of the curable substance received in the tub. An adjustable supply of a process medium into the chamber can at least locally influence the solidification process of the radiation-curable substance. The process medium can be an inhibitor medium in order to influence, in particular to slow down, the hardening process of the radiation-curable substance, in particular on the tub floor, and to change the adhesive force of the last hardened layer on the tub floor. Under an inhibitor medium, a fluid, i.e. a gas or a liquid, e.g. oxygen, understood, which reduces or prevents the hardening of the hardenable substance in a boundary layer (e.g. 10-100 μm) above the tub floor. The inhibitor medium thus reduces (ideally prevents) adhesion of the last hardened layer to the tub floor. By creating an air flow in the chamber, the properties of the medium received in the chamber, e.g. of the inhibitor medium, or mixture of media are homogenized in the chamber. In particular, the temperature of the medium in the chamber and the concentration of the inhibitor medium in the chamber can be homogenized. Furthermore, the diffusion rate of the inhibitor medium and the temperature can be influenced. The air flow source can be a fan or a compressor for setting a volume flow. The volume flow can be generated in the chamber in a closed circuit or in exchange with ambient air.
In order to be able to control the device expediently, it is further advantageous if the sensor is connected via the processing unit to the adjustable pressure source and / or the adjustable heating device and / or the adjustable process material source and / or the air flow source, and the processing unit is set up which Pressure source and / or the heating device and / or the process material source and / or the air flow source as a function of that provided by the sensor
13/98 set sensor signal to control. The sensor detects the current position or movement of the tub floor, at least in the form of a current direction of movement of the tub floor (corresponding to the sign of a change in volume). If the sensor is connected to the adjustable pressure source via the processing unit, the pressure source can be controlled by the processing unit, depending on the current position or movement of the tub bottom, to change the position of the tub bottom by increasing or decreasing pressure. If the sensor is connected to the adjustable heating device via the processing unit, the heating device can be controlled by the processing unit, depending on the current position or movement of the tub base, to change the temperature of the medium in the chamber. If the sensor is connected to the adjustable process material source via the processing unit, the processing material source can be controlled by the processing unit, depending on the current position or movement of the tub base, to change the amount of the process medium to be introduced into the chamber, for example also no process medium into the chamber initiate. If the sensor is connected to the air flow source via the processing unit, the air flow source can be controlled by the processing unit, depending on the current position or movement of the trough bottom, to mix the medium in the chamber by means of an air flow generated by the air flow source.
For an inexpensive manufacture of the tub floor and in order to be able to detect deflections of the tub bottom reliably and as precisely as possible with the sensor, it is favorable if the tub floor is at least partially transparent to radiation and preferably has a flexible, stretched film. As a result, the radiation for curing the curable substance received in the tub can penetrate through the at least partially radiation-permeable tub floor to the curable substance. If the radiation source is arranged below the chamber, the chamber, in particular the chamber floor, is also expediently at least partially transparent to radiation. If the tub bottom has a flexible, stretched film, the film is made sufficiently dense to be undesirable
14/98 prevent penetration of the hardenable substance through the tub floor. The film is preferably designed to be stretched sufficiently to avoid significant sagging of the film, which is burdened by the curable substance, i.e. in order to be able to form essentially flat layers of the body. The film is also preferably designed to be sufficiently elastic in the tensioned state, to deflect towards or away from the chamber floor, i.e. downwards or upwards. The tray floor can have, for example, silicone layers, PTFE or Teflon foils and combinations. The elastic behavior of the trough base serves to minimize the pulling forces which arise from the trough base during the separation process of the last layer produced, which can otherwise lead to damage to the body to be generated or can separate it from the construction platform.
If the trough base is semipermeable, permeable to a process medium, a process medium accommodated in the chamber can penetrate through the trough base and, for example, as an inhibitor medium, the last produced, i.e. Reduce the hardened layer on the tub floor or ideally prevent it. In this way, the removal process of the last layer produced from the tub floor can be accelerated or completely eliminated. For example, the tub floor can be permeable to oxygen as an inhibitor medium. The tub floor is impermeable to the radiation-curable substance. Distilled water, for example, can be used as a further process medium. The water can be brought to a certain temperature, for example 5 ° C. The substance to be cured is cooled by the water at the interface to the tub floor, thus reducing the reactivity in a certain range. This can lead to the formation of an also unreactive boundary layer and thus to a reduction in the adhesion. By using a highly viscous fluid as a process medium, such as silicone oil or special fluorine oils, the film can be supported by the fluid in the exposure area and at the same time the pressure difference caused by the fluid e.g. passed on to a pressure sensor
Will be 15/98.
To relieve the trough bottom, it can be provided that at least part of the trough bottom rests on an at least partially radiation-permeable, in particular transparent, carrier plate. Due to the at least partial support of the tub base on the carrier plate, sagging of the tub base loaded by the hardenable substance, in particular due to aging, can be prevented. The carrier plate thus serves as a support for the tub floor. In order to be able to cure the curable substance by means of a radiation source arranged below the carrier plate, the carrier plate is expediently at least partially transparent to radiation, in particular transparent. For example, the carrier plate can be formed at least partially from glass.
In order to be able to lower the reactivity of the curable substance or to change it in any other way when the carrier plate is present, it can further be provided that the carrier plate is designed to be permeable to a process medium or to have elevations adjacent to the tub floor for the passage of a process medium between the elevations. The process medium can in particular be an inhibitor medium in order to prevent the last produced, i.e. to reduce or prevent hardened layer on the tub floor. Thus, if the carrier plate is permeable to the process medium / inhibitor medium, the process medium / inhibitor medium can penetrate from the chamber through the carrier plate and expediently through the trough bottom to the curable substance. For example, the carrier plate can have nanoporous glass or airgel. In general, the support plate on the side facing the trough bottom can have structuring, in addition to or instead of the elevations, which thus bear against the trough bottom when the device is in use and which can also be realized, for example, by a sufficiently rough or undulating surface of the support plate. The elevations and / or structures are provided so that the process medium / inhibitor medium can flow between the carrier plate and the trough bottom.
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If a doctor blade movable in the tub on the tub floor is provided, the doctor blade can be guided in the hardenable substance over the tub floor. The doctor blade can remove partially hardened particles of the hardenable substance and ensure that the hardenable substance is mixed. In the case of curable substances which have a high viscosity due to the particles contained therein, the doctor blade can serve to smooth the layer to be hardened.
Furthermore, it is favorable if the sensor is connected to a drive unit of the doctor blade via the processing unit, and the processing unit is set up to control the drive unit of the doctor blade depending on the sensor signal provided by the sensor. Optionally, the contact pressure of the squeegee on the trough bottom, which is essential for the function of the squeegee, can be detected by the volume change in the chamber with the sensor. If the doctor blade pressure on the trough bottom is too high or too low, the contact pressure can be controlled by the processing unit and changed via the drive unit of the doctor blade.
According to a further embodiment of the device it can be provided that the trough bottom is an openable, in particular removable, cover of a chamber housing of the chamber. By designing the tub bottom as a lid, an openable access into the chamber can be created. If the trough base is designed to be removable as the cover of the chamber housing, the chamber can be closed by placing the trough on the rest of the chamber housing. The trough bottom can also have at least a part of the side walls of the chamber housing as the cover of the chamber housing. Alternatively, the tub floor and the chamber can be formed in one piece.
With regard to the method, it is also provided according to the invention that the sensor detects a change in volume of a chamber and provides a sensor signal from which a sign of the change in volume can be determined, the chamber being limited by an underside of the tub floor, the volume of the chamber being determined by the process Deflections of the tub floor from the rest position is changeable. The chamber can at least
17/98 partially closed. In some embodiments, the chamber is essentially sealed.
In order to avoid repetitions from the description part relating to the device, reference is also made to the previous description of the device with regard to the description of the method, insofar as this is applicable to the method.
The method is used to build up a layer of a body from a radiation-curable substance, for example from light-curing resin, which is received in a tub. The tub is impermeable to the curable substance and has a tub bottom. For each to be formed, i.e. Layer of the body to be hardened, a height-adjustable building platform is moved with respect to the tub floor to a height above the tub floor, which height defines a distance between the building platform or the last layer of the body to the tub floor to the extent of at least the thickness of the body layer to be formed. The last layer of the body formed, if one has already been formed, adheres to the building platform with the previously formed layers of the body. The radiation-curable substance between the building platform or the last-formed layer of the body and the trough bottom is selectively cured by means of a radiation source by radiation to form the next layer of the body. The radiation source can be a light source. Thereupon, the height-adjustable construction platform with the adhered, last formed or hardened layer of the body is moved away from a rest position of the tub floor in order to create space for the formation of a next layer between the last hardened layer of the body and the tub floor. An at least partially flexible tray base is provided as the tray base, and at least one process parameter is detected by a sensor that interacts with the tray base.
The sensor detects a change in volume of an at least partially closed chamber and provides a sensor signal from which a sign of the change in volume can be ascertained. In this way, it can be determined whether and when the volume of the chamber changes during manufacture
18/98 gear of the body to be built enlarged or reduced. For this purpose, the chamber is bounded by an underside of the tub floor. The volume of the chamber can be / is changed by process-related deflections of the tub base from the rest position. The volume of the chamber thus changes when the flexible trough base is deflected from its rest position in the course of the method. The definition of the rest position depends on the implementation of the method. The rest position can be defined as that position of the tub floor in which the hardenable substance is received in the tub and loads the tub floor. The rest position can also be defined as that position of the tub floor in which no hardenable substance is accommodated in the tub.
According to a preferred embodiment of the method, it can be provided that the sensor quantitatively detects a measurement variable that is directly or indirectly proportional to the volume of the chamber or to the change in volume and provides it as a sensor signal. The volume or the change in volume of the chamber is thus detected by detection of the directly or indirectly proportional measured variable. The sensor is designed to detect this measured variable and to output a sensor signal representing the value of the measured variable.
It is particularly favorable if the sensor is a pressure sensor or flow sensor, with the pressure sensor detecting a change in the pressure of a compressible medium in the chamber that corresponds to the change in volume, or a change in the quantity of substance in the chamber that corresponds to the change in volume with the flow sensor included amount of substance of a fluid is recorded as a measured variable. The pressure, the change in pressure or the change in the amount of substance in the chamber can thus be understood as a measurement variable which is directly or indirectly proportional to the volume of the chamber or to the change in volume of the chamber. In particular, the volume and the volume changes of the chamber and in the case of the pressure sensor the pressure and the pressure changes in the chamber and in the case of the flow sensor the changes in the amount of material in the chamber, from the position or from the deflection of the tub base
19/98 dependent. If the sensor is a pressure sensor, a pressure or a change in pressure in the chamber, in particular a compressible medium accommodated in the chamber, can thus be detected in order to determine the volume or a change in volume of the chamber. For this purpose, the chamber is closed and essentially sealed for the compressible medium. With regard to the tightness of the chamber, reference is made to the previous description of the device. The pressure sensor provides the detected pressure or the detected change in pressure as a sensor signal or output signal. The pressure sensor can preferably detect a reference value for the pressure in the chamber, which reference value is assigned to a rest position of the tub floor.
The reference value is e.g. as long as the process of detaching a hardened layer from the tub floor has not yet started. The pressure sensor can preferably detect deviations from the reference value, which deviations are assigned to the deflections from the rest position of the tub floor. If the sensor is a flow sensor, a change in the amount of substance in the chamber, in particular an amount of substance enclosed in the chamber, of a fluid received in the chamber can be detected in order to determine a change in volume of the chamber. With regard to the design of the chamber with at least one opening acting as an inlet and / or outlet for the fluid and the arrangement of the flow sensor in / on the chamber, reference is also made to the preceding description of the device. With the flow sensor, the direction of the fluid flow and / or measured values of the fluid flow can be detected and made available as a sensor signal or output signal.
In order to be able to simplify the actions required for the production of the 3D body for an operator, it can be provided that the sensor signal provided by the sensor is processed in a processing unit connected to the sensor and at least one method parameter is set depending on the sensor signal provided by the sensor. The at least one process parameter to be set can be determined in the processing unit from the sensor signal provided by the sensor, for example by comparing it with predefined values or by calculation. The processing
For this purpose, the 20/98 unit can have a microprocessor or a microcontroller and can be connected to a data memory. The data memory can contain data and / or program commands for processing the sensor signal provided by the sensor.
Particularly expediently, it can be provided that the processing unit compares the measured variable provided as a sensor signal with an expected value and / or compares a course of measured values (or generally several measured values acquired at several points in time) with a course of expected values (or generally several expected values) and sets the at least one method parameter depending on the difference between the measured variable and the expected value and / or between the course of the measured variables (the multiple measured variables) and the course of the expected values (the multiple expected values). Furthermore, it can be provided that the processing unit compares a change between a plurality of measured variables recorded at different times with an expected value of the change and sets the at least one method parameter depending on the difference between the change and the expected value of the change. The measured variable can also correspond to a rate of change (i.e. change per unit of time) and be compared with an expected value for the rate of change. The expected value or the expected values is / are stored in the processing unit. In particular, the processing unit can compare a course of several measured variables or measured values acquired at several points in time and provided as a sensor signal with a course of expected values and can set the at least one process parameter depending on the difference between the course of the measured variables or measured values and the course of expected values. If a measured variable or measured value is compared with an expected value, the at least one method parameter can be set depending on whether the measured variable exceeds or falls below the expected value. The at least one method parameter can also be set depending on the extent to which the expected value is exceeded or undershot. If several measurands with several Er
21/98 maintenance values can be compared, the setting of the at least one process parameter can be dependent on a relative change in the measured variables compared to the relative change in the expected values, i.e. regardless of absolute measured values.
It can also be provided that changes in the measured variable detected with the sensor and made available as a sensor signal are processed in a processing unit connected to the sensor in a simulation model of the expected values of the assembly process and at least one method parameter is dependent on at least one measured value of the measured variable and / or the Change of measured values is set according to the specification of the simulation model. In this case, the processing unit has a simulation model of the expected values of the assembly process. The simulation model calculates at least one value of at least one method parameter as a function of the current state in the simulation and as a function of input parameters, such as at least one value of the measurement variable detected with the sensor and made available as a sensor signal. Depending on the simulation result, the construction process can be influenced by setting at least one process parameter.
In order to be able to improve the construction process even further, it is favorable if the expected value and / or the multiple expected values is or are calculated by the processing unit as a function of at least one process parameter. In this way, the expected values are adapted to the current situation of the assembly process and the control of the method can be carried out particularly precisely. The at least one method parameter is advantageously the measurement variable detected with the sensor and made available as a sensor signal.
If the processing unit has a simulation model, it is advantageous if the simulation model takes into account at least one set process parameter as an input value. In this way, the simulation model delivers particularly precise results, since previously set process parameters or their values are taken into account as input values in the simulation
22/98 den.
The input value can be specified by the user; For example, this can be the layer thickness, the printing speed, the material used (mechanical properties) etc., as well as combinations of input values. The user can use CAM software (computer-aided manufacturing) to determine the relevant values, for example, which target values are required for the process parameters (process control). The simulation model can adjust the input values if the signal from the sensor injects it.
Furthermore, it can be provided that on the basis of the sensor signal provided by the sensor, the height of the building platform and / or the last hardened layer of the body in relation to the rest position of the tub floor and / or a movement speed of the building platform and / or the size of an area of the last hardened one Layer of the body is determined as a process parameter in the processing unit when the tub floor is deflected from the rest position by movements of the building platform. The simulation model can determine the area of the last hardened layer from the model data defining the body and the progress of the build-up process as process parameters. Thus, by comparing the expected value or the simulation result with the measured variable detected by the sensor, the stated height of the building platform or the last hardened layer of the body, the movement speed of the building platform and / or the size of an area of the last hardened layer of the body can be concluded . For example, the volume of the chamber increases with increasing height of the building platform when the previously formed layers of the body adhere to the building platform and to the tub floor. In addition, the volume of the chamber changes more rapidly with increasing speed of the building platform. A larger area of the last hardened layer of the body adhering to the tub floor will change the volume of the chamber more quickly when lifting the building platform than a smaller area of the last hardened layer of the body adhering to the tub floor.
23/98
Furthermore, it can be provided that, depending on the sensor signal provided by the sensor, a height adjustment of the construction platform by means of a drive unit for the construction platform connected to it and to the processing unit and / or irradiation of the radiation-curable substance by means of a control unit connected to the processing unit and the radiation source is controlled by the processing unit for the radiation source as a process parameter. Thus, by comparing at least one expected value or simulated value of the measurement variable with at least one value of the measurement variable detected by the sensor, the height adjustment of the construction platform and / or the irradiation of the radiation-curable substance can be controlled as process parameters. As an alternative to certain detected values of the measured variable, the processing unit can also use a relative or absolute change in the measured variable in the course of at least a partial section of the construction process to control the aforementioned method parameters.
According to a further embodiment of the method it can be provided that, depending on the sensor signal provided by the sensor, a resting pressure in the chamber by means of at least one adjustable pressure source connected to the chamber and the processing unit and / or a temperature in the chamber by means of at least one with the chamber and the adjustable heating device connected to the processing unit and / or a supply of a process medium into the chamber by means of at least one adjustable process material source connected to the chamber and the processing unit and / or an air flow in the chamber by means of at least one air flow source connected to the chamber and the processing unit as process parameters the processing unit is set.
Thus, by comparing at least one expected value or simulated value of the measurement variable with at least one value of the measurement variable detected by the sensor, the resting pressure in the chamber, a temperature in the chamber, a supply of a process medium, for example inhibitor medium, into the chamber and / or an air flow in the chamber can be set or controlled as a process parameter.
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It can preferably be provided that from the sensor signal provided by the sensor a detachment of a layer of the body that has recently hardened and adheres to the tub floor and / or a detachment height and / or a detachment rate of a layer of the body that has recently hardened and adhered to the tub floor and / or or a probing of the tub floor and / or a contact pressure of a squeegee movable in the tub on the tub floor and / or a body incorrectly detached from the construction platform and / or tub aging and / or an unexpected sticking of the body to the tub floor when an inhibitor medium is fed into the tub Chamber and to the radiation-curable substance and / or a fill level of the radiation-curable substance in the trough and / or provision of the trough and / or a crack or hole in the trough bottom or in the chamber is determined as a process parameter in the processing unit. When a last hardened layer of the body adhering to the tub floor is detached from the tub floor, the rapid volume reduction of the chamber as a result of the independent return of the flexible tub floor to the rest position can be detected. In addition, the measured volume change in the chamber can be a measure of the detachment height or the detachment speed of a layer of the body that has recently hardened and adheres to the tub floor from the tub floor when the construction platform is raised. When touching the tub floor, i.e. if the building platform is lowered against the tub floor and comes into contact with it, the volume of the chamber decreases as soon as the building platform moves the tub floor down compared to the rest position. Furthermore, the volume of the chamber decreases with increasing contact pressure of a doctor blade movable in the tub on the tub floor. A body detached incorrectly from the building platform, which, for example, is only connected to the building platform at one body edge, i.e. is tilted and hanging down, when the building platform approaches the tub floor, it will touch the tub floor at a greater height than the expected height of the building platform above the tub floor and reduce the volume of the chamber. In addition, with increasing age of the tub, the elasticity of the tub bottom can change, which affects the volume of the chamber. An unexpected sticking of the body to the tub floor when one is supplied
25/98
Inhibitor medium into the chamber and further towards the radiation-curable substance also leads to volume values of the chamber when the construction platform is raised, which deviate from expected volume values. The value of the volume of the chamber can also be used to infer the fill level of the radiation-curable substance in the tub, since the curable substance presses on the tub floor. The value of the volume of the chamber can also be used to determine whether a tub has been provided in the device (or else the “chamber is open to the environment). In addition, an unexpected change in the volume of the chamber (in particular an unexpected change in pressure in the case of a pressure sensor and a chamber which is closed per se) indicates a crack or a hole in the tub floor or in the chamber. Thus, from a measurement of a change in volume of the chamber, in particular the absolute or relative values of the pressure or the change in the amount of substance or the speed of the change in pressure or change in the amount of substance, the processing parameters mentioned can be determined by means of the processing unit.
If, depending on the sensor signal provided by the sensor, for detaching a layer of the body that has recently hardened and adhered to the tub floor, in particular while the height-adjustable construction platform is moving away from the rest position of the tub floor, a depression in the chamber deflecting the tub floor away from the building platform is set by the processing unit, the last hardened layer of the body adhering to the tub floor can detach itself from the tub floor at a lower height of the building platform or without lifting the building platform. The suppression which arises when the chamber volume is reduced and therefore, in addition to any restoring force of the tub bottom, pulls the tub bottom away from the construction platform thus supports the detachment of the layer of the body adhering to the tub bottom. The value of the negative pressure is preferably recorded with the sensor (in particular pressure sensor) and can be limited if necessary in order to avoid damage to the body to be manufactured or to the tub base due to excessive negative pressure or a too rapid change in the pressure in the chamber.
26/98
If, depending on the sensor signal provided by the sensor in the chamber, an excess pressure of the inhibitor medium is set by the processing unit, the diffusion through the semipermeable film can be increased. The thickness of the inhibited substance layer that can be influenced thereby is an important process parameter and has an effect, for example, on the printing speed.
If, depending on the sensor signal provided by the sensor, the overpressure in the chamber deflecting the trough floor towards the construction platform is set by the processing unit before touching the building platform or the last hardened layer of the body on the tub floor, a pressure change in the chamber can already occur before reaching the rest position of the bath floor and the rest position of the bath floor can be achieved particularly precisely by lowering the construction platform. The value of the overpressure is preferably detected with the sensor (in particular pressure sensor) and regulated based on it by the control unit in order to avoid damage to the tub floor due to excessive overpressure in the chamber.
For the production of a layer of the body to be formed, it can be provided that the height-adjustable construction platform with a last hardened layer of the body adhering to it and to the tub floor is moved away from a rest position of the tub floor, detaching the layer of the last hardened and adhering to the tub floor Body is determined from the tub floor in the processing unit via the sensor, the height-adjustable construction platform is moved to a height above the rest position of the tub floor, which is a distance between the last hardened layer of the body to the rest position of the tub floor to the extent of at least the thickness of the new layer to be formed of the body, and then the radiation-curable substance for forming the new layer of the body is selectively cured by means of the radiation source by radiation. In this case, the last hardened layer of the body adhering to the tub floor is separated from the tub floor, for example, by lifting the construction platform. The change in volume of the chamber during the lifting of the building platform
27/98 and when the last hardened layer of the body is separated from the tub floor, the sensor is advantageously used. As soon as the separation has been detected, the building platform can be moved down to the desired height above the tub floor, for which purpose the building platform is driven, for example, by a stepper motor. Thereafter, the curable substance in the space between the last hardened layer of the body and the tub floor is hardened by radiation to form a new layer of the body. The hardenable substance is exposed separately from the movement of the building platform (asynchronous mode without inhibition layer).
For the production of a layer of the body to be formed, provision can also be made for an inhibitor medium to be supplied via the chamber of the radiation-curable substance and for the height-adjustable construction platform to move to a height above the rest position of the tub floor with a layer of the body adhering to it, which has recently hardened which defines a distance between the last hardened layer of the body to the rest position of the tub floor at least to the extent of the thickness of the new layer of the body, while at the same time to the method of the height-adjustable construction platform, the radiation-curable substance for forming the new layer of the body is selective is cured by means of the radiation source by irradiation. In this case, the inhibitor medium prevents the last hardened layer of the body from adhering to the tub floor, as a result of which it is not necessary to separate this layer from the tub floor. The space required for the inhibitor medium is taken into account when determining the height to which the construction platform is moved over the tub floor. Thus, the curable substance can be irradiated to the desired height above the tub floor already during the process of building the platform. In this way, the process of manufacturing the body is significantly accelerated. Thus, the exposure of the curable substance and the movement of the building platform take place simultaneously (synchronous mode).
For the production of a layer of the body to be formed, an inhibitor medium can also be provided via the chamber
28/98 of the radiation-curable substance is supplied and the height-adjustable construction platform with an adhering, last hardened layer of the body is moved to a height above the rest position of the bath floor, which is at least a distance between the last hardened layer of the body to the rest position of the bath floor defined in the extent of the thickness of the layer of the body to be newly formed, and then the radiation-curable substance for forming the new layer of the body is selectively cured by means of the radiation source by radiation. In this case, the inhibitor medium prevents the last hardened layer of the body from adhering to the tub floor, as a result of which it is not necessary to separate this layer from the tub floor. The space required for the inhibitor medium is taken into account when determining the height to which the construction platform is moved over the tub floor. The construction platform can be moved to the desired height above the tub floor and then the hardenable substance between the last hardened layer of the body and the tub floor can be irradiated. Because of the elimination of the separation process, the process for manufacturing the body is significantly accelerated. The curing substance is thus exposed separately from the movement of the building platform (asynchronous mode with inhibition layer).
The invention is explained in more detail below on the basis of preferred, non-limiting exemplary embodiments with reference to the drawings. Show it:
Figure 1 shows a device according to the invention with a pressure sensor and a trough bottom without a support plate.
Figure 2 shows a device according to the invention with a pressure sensor and a trough bottom with a support plate.
3 shows a carrier plate with elevations resting on the tub floor;
4 shows the device from FIG. 1 with an at least partially formed body adhering to the tub base;
29/98
5 shows the device from FIG. 2 with an at least partially formed body adhering to the tub base;
6a to 6d the device from FIG. 2 each with an adjustable pressure source, an adjustable heating device, an adjustable process material source (inhibitor source) and an air current source;
7 shows the device from FIG.
8 shows the device from FIG.
FIG. 9 shows the device from FIG. Needed inhibition layer;
10 shows the device from FIG. Needed inhibition layer;
FIG. 11 shows the device from FIG. Needed inhibition layer;
with an inhibition layer;
with an inhibition layer;
with one partially open9 with one even more open8 with one partially openFig. 12 shows a device according to the invention in which the trough bottom is an openable, in particular removable, cover of a chamber housing of the chamber;
13 shows the device from FIG.
FIG. 14 shows the device from the FIG. Building platform;
15 shows the device from FIG. 1 which deflects the construction platform away with a squeegee on the tub floor with one on the tub floor an1 with one of the tub floor in the chamber;
Fig. 16 shows the device from Fig. 2 with a the tub floor
Construction platform deflecting excess pressure in the chamber;
FIG. 17 shows the device from FIG. 1 with an incorrectly partially detached body from the construction platform;
30/98
18a to 18c a detachment process of the last hardened layer of the body from the tub floor in three exemplary states;
19 shows diagrams with exemplary profiles of the volume of the chamber, the pressure in the chamber and the height of the construction platform above the trough bottom for the detaching process illustrated in FIGS. 18a to 18c, in the case of a substantially closed chamber;
20a and 20b show a detachment process of the last hardened layer of one of three bodies from the tub floor in two exemplary states;
21 shows diagrams with exemplary profiles of the pressure in a substantially closed chamber and the height of the construction platform above the tub floor for the detaching process illustrated in FIGS. 20a and 20b;
22 shows a body adhering to the tub floor;
23a to 23c are diagrams with exemplary courses of the height of the construction platform above the tub floor and with the exposure time; and
24 shows a device according to the invention with a flow sensor instead of a pressure sensor.
For the sake of clarity, parts of the device which do not serve to describe the respective figure are omitted from the figures shown.
Those parts of the description which relate to a pressure measurement or detection of the pressure in the chamber are to be understood on the condition that the sensor is a pressure sensor and the chamber is essentially closed. For explanations of the tightness of the essentially closed chamber, reference is made to the preceding description.
31/98
For the sake of clarity, most of the exemplary embodiments are shown and described in connection with an essentially closed chamber and a pressure sensor. If, instead of a pressure measurement, a measurement of the flow of a quantity of substance is intended and possible, a flow sensor which is arranged in an inlet / outlet of the chamber for a fluid can of course be used instead of the pressure sensor. Accordingly, those exemplary embodiments which are shown and described in connection with a pressure sensor, but which can also be implemented in connection with a flow sensor, also apply to versions with a flow sensor.
1 shows a device 1 for a system for the layer-by-layer construction of a body K, which is illustrated, for example, in FIG. 4, from a radiation-curable substance S, with a trough 3 having a trough base 2 for receiving the radiation-curable substance S. The tub floor 2 is shown in its rest position, essentially flat. The device 1 also has a construction platform 4 arranged above the tub floor 2 and height-adjustable in relation to the tub floor 2, and a sensor 5 which interacts with the tub floor 2. The height-adjustable construction platform 4 is in the direction indicated by the double arrow H, i.e. adjustable in height, in relation to the tub floor 2 or generally in relation to the tub 3 up and down. The tub floor 2 is at least partially flexible, in a partial area 13. A chamber 6 is provided below the tub 3, which is shown in FIG.
is closed in order to cooperate with a sensor 5 designed as a pressure sensor 5a. In another embodiment shown in FIG. 24, the chamber 6 can have an opening 34 for the inlet or outlet of a fluid received in the chamber 6, in which case the sensor 5 is a flow sensor 5b. The chamber 6 is delimited by an underside of the tub base 2. The trough base 2 is thus part of a chamber housing 7 of the chamber 6. The sensor 5 can detect a change in volume of the chamber 6 and provide a sensor signal from which a sign of the change in volume can be determined. The sensor 5 can in particular take a measurement that is directly or indirectly proportional to the volume of the chamber or to the change in volume of the chamber
Record 32/98 large quantities and provide them as sensor signals.
In the example shown in FIG. 1, the sensor 5 is a pressure sensor 5a for detecting a pressure or a pressure change corresponding to the change in volume of a compressible medium aufgenommen accommodated in the chamber 6. The chamber 6 is designed to be closed. In another embodiment (FIG. 24), the sensor 5 can be a flow sensor 5b, which is provided for detecting a change in the amount of substance corresponding to the change in volume of the amount of substance contained in the chamber 6 of a fluid received in the chamber 6. The fluid can be a liquid or a gas and therefore can be compressible or uncompressible. For example, the sensor 5 is set up to provide a detected pressure, a detected pressure change or a detected change in the amount of substance as a measured variable and sensor signal.
In the example shown in FIG. 1, a compressible medium M, for example air, is accommodated in the chamber 6, the sensor 5 being a pressure sensor 5a which is set up to detect the pressure of the compressible medium M accommodated in the chamber 6. Pressure sensor 5a is preferably accommodated in chamber 6. In a special embodiment, the pressure sensor 5a can also be designed as a sound transducer. The sensor 5 can be connected to a processing unit 8, which is set up to process the sensor signal provided by the sensor 5, in particular the pressure detected by the pressure sensor 5a or the change in substance quantity detected by the flow sensor 5b. The sensor 5 can be connected via the processing unit 8 to a drive unit 9 for the height-adjustable construction platform 4 and / or to a control unit 10 for a radiation source 11, which is provided for irradiating the radiation-curable substance S. The processing unit 8 is set up to control the drive unit 9 for the height-adjustable construction platform 4 and / or the control unit 10 for the radiation source 11 as a function of the sensor signal provided by the sensor 5. In other exemplary embodiments, not shown, the processing unit 8 can also be connected only to the drive unit 9 for the height-adjustable construction platform 4 or only to the control unit 10 for the radiation source 11
33/98 and be designed to control it. The separation force necessary for the separation of the body K from the tub base 2, which is introduced by the height-adjustable construction platform 4, deflects the tub bottom 2 and thereby produces a change in volume in the chamber 6. When the chamber 6 is closed for use with a pressure sensor 5a, The volume change causes a pressure change in the chamber 6. On the other hand, if the chamber 6 is partially open for use with a flow sensor 5b, the volume change causes a flow (inflow or outflow) of the fluid received in the chamber 6 to equalize pressure with the environment or with another chamber. With increasing radiation energy (product of exposure time and exposure intensity) that is introduced by the radiation source 11, the generated layer of the body K adheres more strongly to the tub floor 2. By comparing the expected minimum pressure (= separation pressure) or flow with the actual separation pressure or flow, it can be concluded that the exposure energy is too high. The drive unit 9 can have, for example, a controllable electric motor, in particular a stepper motor, which engages with a height-adjustable rod 12 and is connected to the construction platform 4 via the rod 12. The trough bottom 2 is at least partially transparent to radiation, i.e. at least partially transparent to the radiation emitted by the radiation source 11 onto the tub floor 2, for example light. The trough base 2 preferably has a flexible, stretched film 13a. The film 13a is provided in the flexible partial area 13. Advantageously, the film 13a is at least partially transparent to radiation, in particular translucent. In the example shown in FIG. 1, the film 13a is stretched between fixed edge parts 14 of the tub base 2. If, as in the example shown in FIG. 1, the radiation source 11 is arranged outside, in particular below, the chamber 6, the chamber bottom 7a of the chamber housing 7 is expediently at least partially transparent to radiation, in particular transparent. An exemplary radiation cone B can be seen in FIG. 1.
Fig. 2 shows the device 1, wherein at least part of the
34/98
Trough bottom 2, in particular the flexible partial area 13, particularly preferably the film 13a, rests on an at least partially radiation-transparent, in particular transparent, carrier plate 15. The carrier plate 15 thus supports an underside of the film 13a in the rest position shown. The film 13a or the tub floor 2 is shown essentially flat in this rest position. The carrier plate 15 can be designed to be permeable to a process medium Mp, in particular an inhibitor medium Mi, and / or have elevations 16 adjacent to the trough bottom 2 for the passage of a process medium Mp, in particular inhibitor medium Mi, between the elevations 16. The raised areas 16 resting on the tub floor 2 can in particular rest on the flexible partial area 13 of the tub floor 2, preferably on the film 13a. The process medium Mp or inhibitor medium Mi, for example oxygen, is accommodated in the chamber 6.
Enables a closed tub construction to have a negative change in volume of the chamber 6, e.g. due to a slight sag of the tub 3, more precisely the tub bottom 2, an increase in pressure can be detected. This can e.g. the level of the curable, e.g. photosensitive substance S in the tub 3 are closed. Furthermore, the zero position of the trough base 2 can be measured relative to the support plate 15, in that a targeted collision of the support plate 15 with the flexible trough base 2 after its separation from a body K leads to a measurable pressure gradient.
FIG. 3 shows a section of a carrier plate 15 with elevations 16 which rest on the tub floor 2. Recesses 17 extend between the elevations 16 in which the process medium Mp, for example the inhibitor medium Mi, can flow. The recesses 17 can be designed, for example, as groove-shaped depressions between strip-shaped elevations 16. If the carrier plate 15 is also designed to be permeable to the process medium Mp, in particular inhibitor medium Mi, channels (not shown) for guiding the process medium Mp, in particular inhibitor medium Mi, can be provided in the carrier plate 15. The carrier plate 15 can also be porous.
35/98
4 shows the device 1 with an at least partially formed body K. The body K has several layers Kl to Kn, which were formed by locally curing the curable substance S with radiation. The body K adheres to the building platform 4 with the first layer Kl and, in the situation shown, before detaching with the last layer Kn to the tub base 2, in particular to the film 13a. In the state shown, the building platform 4 has already been raised a little, i.e. move in positive Z direction and away from the tub 3, whereby the film 13a is deflected from its rest position at least in a partial area. The volume of the chamber 6 is increased by the deflection. This corresponds to a positive sign (“+) of the volume change. As a result, the pressure in the chamber 6 drops (at constant temperature and constant amount of substance, i.e. closed chamber). The pressure sensor 5a is set up to detect this pressure change and to transmit a corresponding signal to the processing unit 8. Likewise, a flow sensor 5b cooperating with a partially open chamber 6 (not shown in FIG. 4) can detect a change in the amount of substance in the chamber 6, which change in the amount of substance corresponds to the increase in the volume of the chamber 6. In particular, in the case of the open chamber 6, fluid is drawn into the chamber 6 by the deflection of the film 13a. The flow sensor 5b can also transmit a corresponding signal to the processing unit 8. For the sake of clarity, the processing unit 8, the drive unit 9 and the control unit 10 are not shown in FIG. 4 or in other figures.
In contrast to FIG. 4, a support plate 15 is provided in FIG. 5, on which the trough base 2, in particular the film 13a, can rest. As can be seen in the situation shown with deflected trough base 2, the trough base 2, more precisely the film 13a, lies only loosely on the carrier plate 15 and can be lifted off from it under the action of an adhering body K. Through the recesses 17 in the carrier plate 15 a pressure equalization within the chamber 6, i.e. between the space between the carrier plate 15 and film 13a on the one hand and the chamber 6 below the carrier plate 15 on the other hand, made possible
36/98 light. The deflection of the trough base 2 thus leads to a change in pressure that can be detected by the pressure sensor 5a or a change in the amount of substance that can be detected by the flow sensor 5b. In FIG. 5 too, a flow sensor 5b can be provided in a partially open chamber 6 (not shown in FIG. 5) instead of the pressure sensor 5a in the closed chamber 6.
6a shows in simplified form the device 1, in which the chamber 6, as a closed chamber 6, is connected, for example, to at least one adjustable pressure source 18 for setting a static pressure in the chamber 6 and the pressure sensor 5a via the processing unit 8 to the adjustable pressure source 18 is connected.
6b shows the device 1, in which the chamber 6 is connected, for example, to an adjustable heating device 19 (or generally a heat exchanger) for setting a temperature in the chamber 6, and the pressure sensor 5a is connected to the adjustable heating device 19 via the processing unit 8 is.
In this example, the chamber 6 has an inlet 27 and an outlet 28. The inlet 27 and the outlet 28 can each be closed by a valve 29, 30, in particular a solenoid valve. The heating device 19 is arranged in a feed line 31 between a compressor 32 and the valve 29 in front of the inlet 27. To change the temperature in the chamber 6, the compressor 32 can be activated at least temporarily, e.g. Suck ambient air through the mouth 33. At the same time, the valves 29, 30 are opened to approximately the same extent, so that compressible medium can emerge from the chamber 6 through the outlet 28 and is replaced by the compressible medium flowing in through the inlet 27, the inflowing medium heating immediately beforehand in the heating device 19 has been. By mixing the compressible medium in the chamber 6 due to the flow, a uniform temperature is quickly established. It can be advantageous if a device for measuring the temperature is provided in the chamber 6 and is optionally connected to the processing unit 8. The heating device 19 is thus used, for example, for indirect heating of the curable substance S. As soon as one is desired
37/98 te temperature is reached, the valves 29, 30 are closed again. When evaluating the pressure changes detected by the pressure sensor 5a, the state of the valves 29, 30 (i.e. closed or open or partially open) is taken into account in order to be able to correctly assign the cause of pressure changes.
6c shows in simplified form the device 1, in which the chamber 6 is connected, for example, to an adjustable process material source 20, in particular an inhibitor source 20a, for the adjustable supply of a process medium Mp, in particular an inhibitor medium Mi, to the chamber 6 and the pressure sensor 5a the processing unit 8 is connected to the adjustable process material source 20, in particular inhibitor source 20a. The process material source 20 is used for at least local manipulation of the solidification process of the radiation-curable substance S in the tub 3. Since in this case the tub bottom 2 can be at least slightly permeable to the process medium Mp, this variant can only do with one inlet and without one outlet . If sensor 5 is designed as a flow sensor 5b, it can be arranged in a connecting line between the process material source 20 and the chamber 6. In this case, the change in volume is inferred from the mass balance; this is proportional to the difference between the inflowing and outflowing medium.
6d shows in simplified form the device 1, in which the chamber 6 is connected, for example, to an air flow source 21 for generating an air flow in the chamber 6 and the pressure sensor 5 a is connected to the air flow source 21 via the processing unit 8. The air flow source 21 serves, for example, to mix the compressible medium Μ accommodated in the chamber 6. As in FIG. 6c, a flow sensor 5b arranged in a connecting line between the air flow source 21 and the chamber 6 can also be used as the sensor 5.
Of course, the chamber 6 of the device 1 can be connected to several of the adjustable pressure source 18, the adjustable heating device 19, the adjustable process material source 20 and the air flow source 21. The processing unit 8 is preferably set up, the pressure source 18 and / or the
38/98
To control the heating device 19 and / or the process material source 20 and / or the air flow source 21 as a function of the sensor signal provided by the sensor 5. Furthermore, the processing unit 8 can preferably be set up to control one or more members of the group consisting of inlet valve 29, outlet valve 30 and compressor 32.
FIG. 7 shows the device 1 with an inhibition layer I formed by an inhibitor medium Mi. In the example shown, the inhibition layer I is formed between the tub floor 2 and the curable substance S. For this purpose, the inhibitor medium Mi is introduced into the chamber 6 through an access (not shown in FIG. 7). In order to be able to supply the inhibitor medium Mi to the curable substance S, the tub base 2, in particular the film 13a, is preferably semipermeable, permeable to the inhibitor medium Mi, or generally a process medium Mp. The inhibitor medium Mi or the inhibition layer I formed thereby reduces the adhesive force with which the last formed layer Kn of the body K adheres to the tub base 2, in particular to the film 13a. The inhibitor medium Mi or the inhibition layer I preferably prevents such adhesion. The example shown in FIG. 7 can also be implemented with a flow sensor 5b in a partially open chamber 6 instead of the pressure sensor 5a in the closed chamber 6. The delta of the inflowing and outflowing medium corresponds to the change in volume.
Tempering the chamber 6 serves, for example, to accelerate the diffusion process of the inhibitor medium Mi through the semipermeable layer (film 13a) but also to heat the curable substance S in the tub 3. The temperature in the chamber 6 has an influence on the temperature of the substance S. and thus the viscosity and the reactivity of the curable substance S to radiation.
In contrast to FIG. 7, a support plate 15 is provided in FIG. 8, on which the tub base 2, in particular the film 13a, can rest. It is useful if the carrier plate 15 for the inhibitor medium Mi, or generally a pro
39/98 process medium Mp, is designed to be permeable and / or has elevations 16 adjacent to the tub floor 2 for the passage of the inhibitor medium Mi or process medium Mp between the elevations 16.
FIG. 9 shows the device 1 in which the inhibition layer I below the body K has been partially used up. This is indicated by the upward curvature of the film 13a and thus by the thinner formation of the inhibition layer I below the body K.
In the example shown in FIG. 10, the inhibition layer I below the body K has been completely used up, which is why the last layer Kn formed of the body K adheres undesirably to the tub base 2, in particular to the film 13a.
The situations according to FIGS. 9 and 10 can be distinguished by the different deflections of the film 13a and the resulting different changes in the volume on the basis of the change in volume detected by the sensor 5. If the sensor 5 is a pressure sensor 5a interacting with a closed chamber 6, the different changes in the pressure in the chamber 6 can be differentiated on the basis of the pressure change detected by the pressure sensor 5a. The processing unit 8 can therefore, for example, signal a lack of inhibitor medium Mi or - preferably - independently ensure timely delivery or distribution of the inhibitor medium Mi into the chamber 6, e.g. by controlling an appropriate inhibitor source 20.
In contrast to FIG. 9, a support plate 15 is provided in FIG. 11, on which the trough base 2, in particular the film 13a, can rest. Due to the elevations 16 and depressions 17, the carrier plate 15 does not change the basic functioning as described above with regard to the distribution of the inhibitor medium Mi.
Fig. 12 shows the device 1 in an embodiment in which the trough bottom 2 is an openable, in particular removable
40/98 rer cover 22 of the chamber housing 7 of the chamber 6 is. In this variant, the chamber is only closed when tub 3 is installed in the system. The chamber housing 7 consists of a chamber base 7a, side parts 7b and an upper chamber part 7c. The trough bottom 2 as the cover 22 of the chamber housing can form the upper chamber part 7c and the side parts 7b as in the example shown in FIG. 12. Thus, the cover 22 is placed on the chamber bottom 7a, which is formed by a bearing surface of the system. The bearing surface, which forms the chamber floor 7a, is at the same time part of the machine housing of a production machine. In another embodiment, the cover 22 can only form the upper chamber part 7c and is placed on the side parts 7b and on the chamber bottom 7a. As an alternative to the closed chamber 6 shown by way of example in FIG. 12, the chamber 6 can be partially open in order to interact with a flow sensor 5b.
13 shows the device 1 with a squeegee 23 that can be moved in the tub 3 on the tub bottom 2, in particular on the film 13a. the pressure sensor 5a or the flow sensor 5b is connected via the processing unit 8 to a drive unit 24 of the doctor blade 23. In the example shown in FIG. 13, the drive unit 24 of the doctor blade 23 is a rod 25 which is displaceably received in the trough 3 and which is moved by a motor 26 controlled by the processing unit 8. The processing unit 8 is set up, for example, depending on the sensor signal detected by the sensor 5, i.e. the pressure in the chamber 6 detected by the pressure sensor 5a or the change in the amount of substance in the chamber 6 detected by the flow sensor 5b to control the drive unit 24 (motor 26) of the doctor blade 23.
14 shows the device 1 in a state in which the construction platform 4, which is lowered in the negative Z direction, probes on the tub base 2, in particular on the film 13a. “Feeling” is understood as touching the tub base 2 or the film 13a through the building platform 4 or through the last hardened layer Kn of the body K without any significant or minimal deflection of the tub bottom 2 or the film 13a. Each additional
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Lowering the construction platform 4 would result in a volume change in the chamber 6 which can be measured by the sensor 5 (pressure sensor 5a or flow sensor 5b) (ie a reduction in the volume and a resulting increase in the pressure when the chamber 6 is closed or a resulting reduction in the amount of fluid in the chamber 6 partially open chamber 6).
15 shows the device 1 in a state in which to remove a recently hardened layer Kn of the body K adhering to the tub floor 2 from the tub floor 2, in particular while the height-adjustable construction platform 4 is moving away from the rest position of the tub floor 2 2 from the construction platform 4 deflecting negative pressure in the chamber 6 was set by the processing unit 8. In Fig.
In the example shown, the construction platform 4 has already been moved upwards a little, in the positive Z direction. The vacuum in the chamber 6 is set as a function of the pressure in the chamber 6, in particular the pressure sensor 5a. For this purpose, the pressure sensor 5a is connected via the processing unit 8 to a compressor 32 connected to the chamber 6. The compressor 32 can preferably be operated in both directions, i.e. to generate an overpressure or underpressure in the chamber 6 as soon as the valve 29 in front of the inlet 27 is opened. The suppression is indicated in Fig. 15 by vertically downward arrows. To generate the negative pressure in the chamber 6, the latter is closed or at least closable.
16 shows the device 1 in a state in which, prior to probing the building platform 4 or the last hardened layer Kn of the body K on the tub floor 2, an overpressure in the chamber 6 deflecting the tub floor 2 to the building platform 4 is set by the processing unit 8 has been. In the example shown in FIG. 16, the construction platform 4 has already been moved down a little, in the negative Z direction, in order to contact the tub floor 2. The overpressure in the chamber 6 is set as a function of the pressure in the chamber 6, in particular the pressure sensor 5a. For this, the pressure sensor 5a is connected to the chamber 6 via the processing unit 8
42/98 connected compressor 32 connected. The excess pressure causes the film 13a to bulge upwards. As a result, probing can also be used when using a carrier plate 15 in order to use the pressure sensor 5a to detect a probing point in time on the basis of a sudden rise in pressure. To generate the excess pressure in the chamber 6, the chamber 6 is closed or at least closable.
At the start of the production of a body K, the building platform 4 is lowered to such an extent that it is in the region of a layer thickness (preferably 10 pm to 300 pm) above the tub floor 2. The subsequent exposure of the first layer K 1 of the body K to be produced is usually carried out with increased energy input in order to ensure that the layer K 1 adheres securely to the building platform 4. Due to, for example, the accuracy of the height positioning of the building platform 4, the tub aging and due to differences in the tub production, the distance between the building platform 4 and the tub floor 2 can vary, so that the adherence of the first layer Kl cannot always be guaranteed. An active probing of the tub bottom 2 by the construction platform 4, as shown in FIG. 16, therefore makes sense and prevents the problems listed above. For this purpose, the pressure in the chamber 6 is increased via the compressor 32 or a pressure source 18 (see FIG. 6a), so that a slight, convex curvature of the trough bottom 2 is produced, as in FIG. 16. The building platform 4 then moves in the direction of the tub floor 2, i.e. downward. As soon as the construction platform 4 touches the curved trough base 2, the pressure in the chamber 6 rises further. The construction platform 4 can be moved further in the direction of the tub floor 2 until the pressure no longer changes, then the tub floor lies against the carrier plate 15 and is pressed flat. Another method in the negative Z direction leads, for example, to a step loss in the stepper motor or to damage to the tub.
FIG. 17 shows an error case in which a body K has detached from the construction platform 4 in an undesired manner. Such a fault can be detected with the sensor 5 (pressure sensor 5a or flow sensor 5b) because a white
43/98 further movement of the construction platform 4 downwards, in the negative direction, leads to a premature volume reduction (pressure increase or quantity reduction) in the chamber 6. The prematurity of the volume reduction can be determined and recognized from the expected height of the body K on the basis of the layers Kl-Kn already generated and the path of the construction platform 4 reported by the stepping motor in comparison with the time of the volume reduction detected by the sensor 5.
18a to 18c show how the curved trough base 2 detaches from the last hardened layer Kn of the body K, the height of the building platform 4 being changed (Z1 <Z2 <Z3). In FIG. 18a, the construction platform 4 has already been moved a little in the positive z direction. In FIG. 18b, the construction platform 4 has been moved further in the positive z direction and a partial separation has already taken place. In FIG. 18c, the construction platform 4 has been moved a little further in the positive z direction and the trough bottom 2 has completely detached itself from the body K at this point in time and has returned to its rest position. As a result, the volume of the chamber 6 has decreased, which corresponds to a negative sign of the change in volume.
19 shows time profiles of the volume of the chamber 6, the sign of the change in volume of the volume, the change in pressure resulting from the change in volume in the chamber 6 when it is closed, and the Z position or height of the building platform 4 with respect to the rest position of the tub floor 2, during a layer generation monitored by the sensor 5, in particular the pressure sensor 5a. At the beginning, the curable, for example light-curing substance S is cured with a desired cross-sectional shape in order to form a layer Kn. Subsequently, the hardened layer Kn, which has arisen between the tub base 2 and the previously generated layer Kn-1, must be separated from the tub bottom 2. From t _start , the construction platform 4 is moved from z _x in the positive Z direction. Due to the flexible design of the tank bottom 2 is of concavely deformed in the Z direction, and the volume in the chamber 6 rises from the normal volume V _nO rm ^(cf..
Fig. 18a shortly thereafter). The positive volume change (sign "+ or" 1) has a proportional pressure reduction of p _norm
44/98 result, this is detected by the pressure sensor 5a. Depending on the cross-sectional shape, layer thickness, material and many other factors, the generated layer Kn detaches from the tub floor 2 as soon as the height z _sep (at time t _sep ) has been reached (cf. FIG. 18c). The arched trough base 2 suddenly moves back to its flat original shape (rest position). Depending on the design and material of the trough base 2, damped vibration can occur. The transition of the tub floor 2 to the rest position leads to a rapid negative change in volume (sign or "-1) which results in V _norm and thus to a measurable change in pressure from p _sep to p _nO rm. The detachment time or separation time t _sep can thus be determined, for example the change in sign of the volume change from "1 to" -1 can be recognized during the separation process (the sign of the volume change can optionally be determined as the opposite sign of the pressure change). As a result, the separation process, ie the raising of the building platform 4, can be ended and the building _platform can be moved (lowered) from z _sep to z _{x + 1} . At t _disp there is material _displacement , which concave the trough bottom 2 and reduces the volume of the chamber 6 so that the measured pressure rises. At time t _end , the Z position z _{x + 1} , at which the new layer is to be generated, is reached. The pressure in the chamber p _d t _sp is greater than p _nO rm. Therefore, the irradiation, for example exposure, is only initiated at the time t _next . This ensures that the material displacement, which is characterized by a flat trough bottom 2 and a resulting chamber pressure p _norm , is completed. The exposure period is shown in the diagram of the Z position by checkered rectangles. Knowing the time of separation t _sep is very valuable in terms of process technology, since without this an expected separation _height z _sep must be assumed and this must be _treated with sufficient security in order to achieve a separation in any case. This means that the building platform 4 (without knowing the time of separation t _sep ) is often moved further in the positive Z direction, although the layer Kn has already detached from the tub floor 2. Several seconds per shift are used free of charge. Usual bodies to be generated consist of over 1000 layers, so the print job is extended
45/98 considerable without knowing the time of separation t _sep .
20a and 20b show a separation process of three bodies K from the tub floor 2, the body K shown on the right most has already detached from the tub bottom 2 in FIG. 20b and the tub bottom 2 in the region below the body K shown on the right has returned to its rest position. On the basis of the change in volume (pressure change or change in quantity of matter) in chamber 6 detected by sensor 5 (pressure sensor 5a or flow sensor 5b), it can be determined whether individual bodies K have not yet been detached.
21 shows time profiles of the pressure change and the Z position or height of the construction platform 4 in relation to the rest position of the tub floor 2 during a layer generation monitored by the sensor 5, in particular the pressure sensor 5a. At the time t _sepl, the body K shown on the far right _detaches from the tub floor 2, at time t _sep2 the body K shown in the middle of the tub _floor 2 and at time _{t sep3} the body K shown on the left from the tub floor 2. The three local _ones The release pressures Psepi>Psep2> Psep3 of the three generated bodies K are the minimum over the course of the pressure change. The exposure period is represented by checkered rectangles in the diagram of the Z position.
22 is a static force model of the separation process (separation process) for a possible calculation of the target volume change with which the actual volume changes can be compared. As a result, the generated bodies K can also be assigned to the individual separation times.
The pull-off force F _Ob j, the restoring force of the deflected trough base 2 F _vat , the weight force of the filled resin as hardenable substance S PrVrQ, as well as the forces arising in the machine room (A _vat - A _Ob j) p _atm and in the Tub chamber 6 A _vat p _vat .
The following applies:
46/98 ζ, ί - θ - F _0b j Fvat PrVr9 (/ ^ vat ^ Obj) Patm + ^ vatPvat
Fobj F _vat ~ PrVr9 + Avat AobjjPatm ^ vatPvat
The known forces are by knowing the material properties and level as well as by measuring the pressure on the right side of the above equation. A machine room can be understood as a general room in the machine, this can also be the installation space.
Since the shape and position of A _Ob j is known, the Z height and the material properties of the film 13a, F _{vat can be used to} approximately calculate / predict. The deduction force F _Ob j can thus be concluded. This affects the object quality and can lead to unwanted detachment from the construction platform 4. It can also serve as a reference variable in a control loop, with the take-off speed as a manipulated variable.
Furthermore, the film curvature can be calculated due to the deflection using the known parameters. The resulting change in target volume can be compared by the sensor data with an actual change in volume, which results as follows.
The change in state of the chamber results from:
P1 * V1 _ P '2 * Λ T ₂
Wherein the volume V ₂ = V + AV _is valid, thereby the IstVolumenänderung be calculated.
iPi T ₂ P2 ^T i>
A too large deviation between the target and actual volume <JV _soii ) indicates a decrease in the tub stiffness, whereby the tub aging or the quality of the tub 3 can be assessed.
The device and the method thus make it possible, with the aid of the known position of the building platform 4, and the known curing positions, e.g. in the form of an exposure matrix, to model the target deformation of the flexible tub base 2 and to compare the resulting target pressure change (target volume change) with the actual pressure change (volume change). Deviations indicate, among other things, a change in the tub stiffness, whereby the tub aging or the quality of the tub 3 can be assessed.
FIGS. 23a to 23c show relationships between the height adjustment of the building platform 4 and the exposure time of the curable substance S for three process sequences. The exposure period is shown in the diagrams by checkered rectangles.
23a shows in particular a method in which the exposure of the curable substance S takes place separately from the movement of the construction platform 4 without using an inhibition layer I (asynchronous mode without inhibition layer I). The building platform 4 moves upwards in the positive Z direction in order to separate the generated layer from the tub floor 2. On the basis of the measured values from sensor 5 (pressure sensor 5a or flow sensor 5b), the separation of the generated layer from the tub floor 2 is recognized and the raising of the construction platform 4 is ended. The building platform 4 is lowered again and after a displacement waiting time the next layer is exposed. The measured values of sensor 5 (pressure sensor 5a or flow sensor 5b) are used in the asynchronous process with tub 3 without inhibition layer I to identify the time of detachment and to set the take-off speed by means of the maximum permissible volume change per unit of time.
23b shows, in particular, a method in which the exposure of the curable substance S and the movement of the building platform 4 by the height occur one layer thickness upwards (synchronous mode, with inhibition layer I). The pressure sensor 5a and the flow sensor 5b can be used here
48/98 are used to monitor the fill level of the tub 2 and / or the consumption of the inhibition layer and thus a suitable control of the pressure in the chamber 6, a supply of inhibiting medium in the chamber 6 and an adjustment of the temperature in the chamber 6 enable.
23c shows in particular a method in which the exposure of the curable substance S takes place one layer thickness upwards after the movement of the building platform 4 by using an inhibition layer I (asynchronous mode with inhibition layer I).
24 shows a device 1 according to the invention similar to device 1 from FIG. 1, in contrast to device 1 from FIG. 1, instead of pressure sensor 5a, which interacts with a closed chamber 6, a flow sensor 5b is provided, which cooperates with a partially open chamber 6. The partially open chamber 6 has an opening 34 serving as an inlet and outlet for fluid. Thus, in the event of a change in volume of the chamber 6, the fluid enclosed or contained in the chamber 6 can be inserted or opened through the opening 34. emanate. This fluid flow through the opening 34 is detected by the flow sensor 5b. Those skilled in the art will understand that in some of the exemplary embodiments shown in the figures, in particular depending on the method steps carried out with the device 1, the closed chamber 6 with the pressure sensor 5a can be replaced by a partially open chamber 6 with the flow sensor 5b.

权利要求:
Claims (31)
[1]
1. Device (1) for a system for the layer-by-layer construction of a body (K) from a radiation-curable substance (S), with a trough (2) having a trough (3) for receiving the radiation-curable substance (S) , with a construction platform (4) arranged above the tub floor (2) and height-adjustable in relation to the tub floor (2), and with a sensor (5) interacting with the tub floor (2), the tub floor (2) being at least partially flexible characterized in that a chamber (6) is provided, the chamber (6) being delimited by an underside of the trough bottom (2), the sensor (5) being set up to detect a change in volume of the chamber (6) and to provide a sensor signal from which a sign of the volume change can be determined.
[2]
2. Device according to claim 1, characterized in that the sensor (5) is set up to quantitatively detect a measurement variable which is directly or indirectly proportional to the volume of the chamber or to the change in volume and to provide it as a sensor signal.
[3]
3. The device as claimed in claim 2, characterized in that the sensor (5) is a pressure sensor (5a) and / or a pressure sensor (5) set up to detect a pressure and / or a change in pressure corresponding to the change in volume of a compressible medium (M) accommodated in the chamber (6). or a flow sensor set up and arranged to detect a change in the amount of substance corresponding to the change in volume of the amount of substance contained in the chamber (6) of a fluid received in the chamber, the sensor (5) being set up, a detected pressure and / or a detected pressure change and / or to provide a detected change in the amount of substance as a measured variable and sensor signal.
[4]
4. Device (1) according to one of claims 1 to 3, characterized in that the sensor (5) is connected to a processing unit (8) which is set up to process the sensor signal provided by the sensor (5).
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[5]
5. The device (1) according to claim 4, characterized in that the sensor (5) via the processing unit (8) with a drive unit (9) for the height-adjustable construction platform (4) and / or with a control unit (10) for a radiation source (11), which is provided for the irradiation of the radiation-curable substance (S), and the processing unit (8) is set up, the drive unit (9) for the height-adjustable construction platform (4) and / or the control unit (10 ) for the radiation source (11) as a function of the sensor signal provided by the sensor (5).
[6]
6. Device (1) according to one of claims 1 to 5, characterized in that the chamber (6) with at least one adjustable pressure source (18) for setting a static pressure in the chamber (6) and / or an adjustable heating device (19) for setting a temperature in the chamber (6) and / or an adjustable process material source (20) for the adjustable supply of a process medium (Mi) for at least local manipulation of the solidification process of the radiation-curable substance (S) into the chamber (6) and / or an air flow source (21) for generating an air flow in the chamber (6) is connected.
[7]
7. The device (1) according to claim 4 and claim 6, characterized in that the sensor (5) via the processing unit (8) with the adjustable pressure source (18) and / or the adjustable heating device (19) and / or the adjustable process material Source (20) and / or the air flow source (21) is connected, and the processing unit (8) is set up, the pressure source (18) and / or the heating device (19) and / or the process material source (20) and / or the air flow source (21) depending on the sensor signal provided by the sensor (5).
[8]
8. The device (1) according to any one of claims 1 to 7, characterized in that the trough bottom (2) is at least partially transparent to radiation and preferably has a flexible, stretched film (13a).
[9]
9. Device (1) according to one of claims 1 to 8, characterized ge
51/98 indicates that the tub base (2) is semi-permeable and permeable to a process medium (Mi).
[10]
10. The device (1) according to any one of claims 1 to 9, characterized in that at least part of the trough base (2) rests on an at least partially radiation-transparent, in particular transparent carrier plate (15).
[11]
11. The device (1) according to claim 10, characterized in that the carrier plate (15) for a process medium (Mp) is designed to be permeable or on the trough bottom (2) adjacent ridges (16) for the passage of a process medium (Mp) between the ridges (16).
[12]
12. The device (1) according to any one of claims 1 to 11, characterized in that a squeegee (23) is provided in the tub (3) on the tub floor (2).
[13]
13. The device (1) according to claim 4 and claim 12, characterized in that the sensor (5) via the processing unit (8) is connected to a drive unit (24) of the doctor blade (23), and the processing unit (8) is set up to control the drive unit (24) of the doctor blade (23) depending on the sensor signal provided by the sensor (5).
[14]
14. The device (1) according to any one of claims 1 to 13, characterized in that the trough bottom (2) is an openable, in particular removable cover (22) of a chamber housing (7) of the chamber (6).
[15]
15. Method for building up a layer (K) of a radiation-curable substance (S), which is received in a tub (3) which has a tub bottom (2), in which for each layer to be formed (Kl,. .. Kn) of the body (K) a building platform (4) which is height-adjustable in relation to the tub floor (2) is moved to a height above the tub floor (2) which is a distance between the building platform (4) or the last layer formed ( Kn) of the body (K) to the tub floor (2) to the extent of at least the thickness of the layer to be formed (Kn + 1) of the
52/98
Body (K) defined, the radiation-curable substance (S) to form the layer (Kn + 1) of the body (K) is selectively cured by means of a radiation source (11) by radiation, and the height-adjustable construction platform (4) with it adhering, hardened layer (Kn + 1) of the body (K) is moved away from a rest position of the tub floor (2) to make room for the formation of a next layer (Kn + 2) between the hardened layer (Kn + 1) of the body (K) and the tub floor (2), the tub floor (2) being at least partially flexible and at least one process parameter being detected by a sensor (5) interacting with the tub floor (2), characterized in that the sensor ( 5) a change in volume of a chamber (6) is detected and a sensor signal is provided, from which a sign of the change in volume can be determined, the chamber (6) being delimited by an underside of the tub base (2), the volume of the chamber (6) can be changed from the rest position by process-related deflections of the tub floor (2).
[16]
16. The method according to claim 15, characterized in that the sensor (5) quantitatively detects a measured variable which is directly or indirectly proportional to the volume of the chamber (6) or to the change in volume and provides it as a sensor signal.
[17]
17. The method according to claim 16, characterized in that the sensor (5) is a pressure sensor (5a) or flow sensor (5b), with the pressure sensor (5a) corresponding to the change in volume of the pressure of a compressible medium (M) in the chamber (6) is recorded as a measured variable or a change in the amount of substance corresponding to the change in volume of the quantity of substance of a fluid enclosed in the chamber (6) is recorded as a measured variable with the flow sensor.
[18]
18. The method according to any one of claims 15 to 17, characterized in that the sensor signal provided by the sensor (5) is processed in a processing unit (8) connected to the sensor (5) and at least one method parameter is dependent on that provided by the sensor (5) Sensor signal is set.
53/98
[19]
19. The method according to claim 18 and claim 16 or 17, characterized in that the processing unit (8) compares the measured variable provided and provided as a sensor signal with an expected value and / or compares a course of detected measured variables with a course of expected values and the at least one process parameter depending on the difference between the measured variable and the expected value and / or between the course of the measured variables and the course of the expected values.
[20]
20. The method according to claim 18 and claim 16 or 17, characterized in that changes in the measured variable detected with the sensor (5) and provided as a sensor signal in a processing unit (8) connected to the sensor (5) in a simulation model of the expected values of the assembly process are processed and at least one method parameter is set as a function of at least one measured value of the measured variable and / or the change in measured values according to the specification of the simulation model.
[21]
21. The method according to claim 19, characterized in that the expected value and / or the multiple expected values is or are calculated as a function of at least one process parameter by the processing unit (8).
[22]
22. The method according to claim 20, characterized in that the simulation model takes into account at least one set method parameter as an input value.
[23]
23. The method according to any one of claims 18 to 22, characterized in that based on the sensor signal provided by the sensor (5), the height of the building platform (4) and / or the last hardened layer (Kn) of the body (K) in relation to the rest position of the tub floor (2) and / or a movement speed of the building platform (4) and / or the size of an area of the last hardened layer (Kn) of the body (K) is determined as a process parameter in the processing unit (8) when the tub floor (2) is deflected from the rest position by movements of the building platform (4).
54/98
[24]
24. The method according to any one of claims 18 to 23, characterized in that, depending on the sensor signal provided by the sensor (5), a height adjustment of the construction platform (4) by means of a drive unit (9) connected to it and to the processing unit (8) for the Construction platform (4) and / or irradiation of the radiation-curable substance (S) by means of a control unit (10) for the radiation source (11) connected to the processing unit (8) and the radiation source (11) as process parameters by the processing unit (8) is controlled.
[25]
25. The method according to any one of claims 18 to 24, characterized in that, depending on the sensor signal provided by the sensor (5), a resting pressure in the chamber (6) by means of at least one connected to the chamber (6) and the processing unit (8) adjustable pressure source (18) and / or a temperature in the chamber (6) by means of at least one adjustable heating device (19) connected to the chamber (6) and the processing unit (8) and / or a supply of a process medium (Mp) into the chamber (6) by means of at least one adjustable process material source (20) connected to the chamber (6) and the processing unit (8) and / or an air flow in the chamber (6) by means of at least one with the chamber (6) and the processing unit (8) connected air flow source (21) is set as a process parameter by the processing unit (8).
[26]
26. The method according to any one of claims 18 to 25, characterized in that, from the sensor signal provided by the sensor (5), a detachment of a layer (Kn) of the body (K) of the body (K) which has recently hardened and adheres to the tub base (2) from the tub bottom (2) and / or a peeling height and / or a peeling speed of a layer (Kn) of the body (K) of the body (K) from the tub bottom (2) that has recently hardened and adheres to the tub bottom (2) and / or a probing of the tub bottom (2) and / or a contact pressure in the tub (3) movable squeegee (23) on the tub floor (2) and / or an incorrectly detached from the construction platform (4) body (K) and / or a tub aging and / or an unexpected adhesion of the body (K) on Tub floor (2)
55/98 drove an inhibitor medium (Mi) into the chamber (6) and to the radiation-curable substance (S) and / or a fill level of the radiation-curable substance (S) in the tub (3) and / or a provision of the Trough (3) and / or a crack or hole in the trough bottom (2) or in the chamber (6), is determined as a process parameter in the processing unit (8).
[27]
27. The method according to any one of claims 18 to 26, characterized in that, depending on the sensor signal provided by the sensor (5), for detaching a layer (Kn) of the body (K) of the body (K) which has recently hardened and adheres to the tub base (2) (2), in particular while the height-adjustable building platform (4) is moving away from the rest position of the tub floor (2), a vacuum deflecting the tub floor (2) away from the building platform (4) in the chamber (6) by the processing unit (8) is set.
[28]
28. The method according to any one of claims 18 to 27, characterized in that, preferably depending on the sensor signal provided by the sensor (5), before touching the building platform (4) or the last hardened layer (Kn) of the body (K) on the tub floor (2), an overpressure deflecting the tub floor (2) towards the building platform (4) in the chamber (6) is set by the processing unit (8).
[29]
29. The method according to any one of claims 18 to 28, characterized in that the height-adjustable construction platform (4) with a last-hardened layer (Kn) of the body (K) adhering to it and to the tub base (2) from a rest position of the tub bottom (2 ) is moved away, detachment of the last hardened layer (Kn) of the body (K) adhering to the tub bottom (2) from the tub bottom (2) is determined in the processing unit (8) via the sensor (5), the height-adjustable construction platform ( 4) is moved to a height (Zx + 1) above the rest position of the tub floor (2), which is a distance between the last hardened layer (Kn) of the body (K) to the rest position of the tub floor (2) to the extent of at least the thickness of the new layer (Kn + 1) of the body (K) to be formed, and then the radiation-curable substance (S) to form the new one
56/98
Layer (Kn + 1) of the body (K) is selectively cured by means of the radiation source (11) by radiation.
[30]
30. The method according to any one of claims 18 to 29, characterized in that an inhibitor medium (Mi) via the chamber (6) of the radiation-curable substance (S) is supplied and the height-adjustable construction platform (4) with an adhered, last hardened Layer (Kn) of the body (K) is moved to a height (Zx + 1) above the rest position of the tub floor (2), which is a distance between the last hardened layer (Kn) of the body (K) to the rest position of the tub floor (2 ) defined at least to the extent of the thickness of the new layer (Kn + 1) of the body (K), while at the same time as moving the height-adjustable construction platform (4) the radiation-curable substance (S) to form the new layer (Kn + 1 ) of the body (K) is selectively cured by means of the radiation source (11) by radiation.
[31]
31. The method according to any one of claims 18 to 30, characterized in that an inhibitor medium (Mi) is supplied via the chamber (6) of the radiation-curable substance (S) and the height-adjustable construction platform (4) with an adhered, last hardened Layer (Kn) of the body (K) is moved to a height (Zx + 1) above the rest position of the tub floor (2), which is a distance between the last hardened layer (Kn) of the body (K) to the rest position of the tub floor (2 ) at least to the extent of the thickness of the new layer (Kn + 1) of the body (K) defined, and then the radiation-curable substance (S) to form the new layer (Kn + 1) of the body (K) selectively by means of the radiation source (11) is cured by radiation.

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同族专利:

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公开号 | 公开日

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JP2022502288A|2022-01-11|

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WO2020070136A1|2020-04-09|

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BR112021003635A2|2021-05-18|

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US20220032538A1|2022-02-03|

---

EP3860827A1|2021-08-11|

---

CN112789157A|2021-05-11|

---

AU2019352000A1|2021-03-18|

---

CA3114824A1|2020-04-09|

---

KR20210069057A|2021-06-10|

---

AT521717B1|2021-04-15|

引用文献:

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AT518566A1|2016-04-25|2017-11-15|Way To Production Gmbh|Device for forming dimensionally stable objects|

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US20180194080A1|2017-01-12|2018-07-12|Global Filtration Systems, A Dba Of Gulf Filtration Systems Inc.|Method of making three-dimensional objects using both continuous and discontinuous solidification|

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AT553910T|2007-07-04|2012-05-15|Envisiontec Gmbh|METHOD AND DEVICE FOR PRODUCING A THREE-DIMENSIONAL OBJECT|WO2020223817A1|2019-05-08|2020-11-12|Forcast Research & Development Corp.|Improved stereolithography system|

法律状态:

优先权:

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申请号 | 申请日 | 专利标题

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ATA50838/2018A|AT521717B1|2018-10-01|2018-10-01|Device for a system for building up a body in layers|ATA50838/2018A| AT521717B1|2018-10-01|2018-10-01|Device for a system for building up a body in layers|

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US17/280,292| US20220032538A1|2018-10-01|2019-10-01|Detection of deformation of vats|

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AU2019352000A| AU2019352000A1|2018-10-01|2019-10-01|Deformation detection of troughs|

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CA3114824A| CA3114824A1|2018-10-01|2019-10-01|Detection of deformation of vats|

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KR1020217010780A| KR20210069057A|2018-10-01|2019-10-01|Deformation detection of gutters|

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CN201980064278.6A| CN112789157A|2018-10-01|2019-10-01|Detection of groove deformation|

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PCT/EP2019/076609| WO2020070136A1|2018-10-01|2019-10-01|Deformation detection of troughs|

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EP19791169.6A| EP3860827A1|2018-10-01|2019-10-01|Deformation detection of troughs|

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BR112021003635-0A| BR112021003635A2|2018-10-01|2019-10-01|vats deformation detection|

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JP2021518082A| JP2022502288A|2018-10-01|2019-10-01|Detection of tank deformation|