• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    In an extrusion head, in particular a printhead for the layered application of material for the generative production of a shaped body, comprising an extrusion die and a heater for melting the polymer material supplied to the extrusion die, the heating means is designed as an inductive heater comprising an inductor surrounding the extrusion die, wherein the extrusion nozzle consists at least partially of an inductively heatable material.
    公开号:AT520657A1
    申请号:T70/2018
    申请日:2018-03-15
    公开日:2019-06-15
    发明作者:
    申请人:Konrad Schreiner；
    IPC主号:
    专利说明:

    The invention relates to an extrusion head, in particular a printing head for the layered application of material for the generative production of a shaped body, comprising an extrusion die with an extrusion channel and a
    Heating device for the melting of the polymer material supplied to the extrusion die.
    Generative manufacturing processes, also known as 3D printing processes, are characterized by the fact that the structure of a shaped body takes place in layers. Usually, each line or pointwise repeated
    Work level and moved site selectively applied material and the work plane then moved up. Depending on the application, the layer thicknesses are between 0.025 and 1.25 mm or above. The basis for 3D printing processes are computer models of the object to be manufactured, which can be generated, for example, with the aid of CAD software. In this case, a height layer plan of the object to be manufactured is produced, in which a production grid is generated for each layer, which defines to which cells of the grid site-selective production material is to be stored and solidified.
    The invention preferably relates to a 3D
    Printing process, referred to as Fused Deposition Modeling (FDM) or Fused Filament Fabrication (FFF), in which a molded body of a meltable plastic is built up in layers. For this purpose, first of all, a liquefaction of a plastic or plastic material, which is usually supplied in wire form from a material supply, takes place
    Wax material (filament) by heating and subsequently the application of the liquefied material by
    Extrusion by means of a nozzle and finally a hardening of the material by cooling at the desired position of the working plane. The material application can be strand-shaped or punctiform. Presently, for the FDM process, molding waxes and thermoplastics, e.g. Polyethylene, polypropylene, polylactide, ABS, PETG and thermoplastic elastomers can be used.
    The filament material is heated and extruded typically by means of a printhead, also referred to as "hot-end." The filament is conveyed through a heated chamber of the printhead in conventional FDM processes and melted thereon.The molten material passes through the die It is very important to maintain exact temperature conditions inside the print head, so that the temperature at the end of the heated chamber facing the extrusion nozzle must be high enough to maintain the temperature
    To convert filament material in the molten state. About the extrusion die, which is firmly connected or bolted to the chamber, the melt 'goes outside and is deposited on a building platform. On the other hand, the temperature must not be too high at the material inlet side of the heated chamber, because here the still solid filament is pushed. Only the feeding of filament at the chamber entrance leads to pushing out of molten material at the extrusion nozzle. If the temperature at the chamber entrance is too high, the filament softens and due to the lack of strength, it can not be pushed back. 3D printing using the FDM process can also fail if the temperature at the end of the nozzle is too low and the material is insufficiently melted. The nozzle is then blocked by unmelted material. This is just at higher
    Material throughputs a common problem.
    The present invention therefore aims to further develop an extrusion head, in particular a printing head for a 3D printer, in such a way that compliance with predefined temperature conditions in the extrusion head is simplified and adaptation of the temperature conditions to changing filament material can be made possible.
    To achieve this object, the invention essentially provides in a device of the type mentioned above that the heating device is designed as an inductive heater, which comprises an inductor surrounding the extrusion nozzle, wherein the extrusion nozzle consists at least partially of an inductively heatable material.
    The fact that the melting of the material by means of an inductive heating, the control of the heating power is much easier, the melting takes place directly in the extrusion die, so that can be dispensed with a separate, the extrusion nozzle upstream heating zone or heating chamber, so that with the upstream heating zone or chamber associated problems eliminated. Another advantage of inductive heating is the non-contact energy transfer from the inductor to the inductively heatable material of the extrusion die, so that the nozzle body, if it does not consist entirely of the inductively heatable material, can be used for mechanical fixation, thermal insulation or heat dissipation ,
    In order to improve the heat dissipation, it can preferably be provided that the extrusion die is held in a surrounding insulating body for thermal and possibly electrical insulation, which preferably consists of a ceramic material.
    The insulating body may have an annular cross-section and optionally be provided with axial openings in order to increase the surface available for heat dissipation, which is sometimes forced to flow through conveyed air. In addition, through these openings, the supply of cooling air to the relevant points in 3D printing, primarily to the pressure peak allows.
    Preferably, the inducer, such as e.g. at least one induction coil, arranged in or on the insulating body. However, the induction coil can also be separated from the insulating body attached to another component. The at least one induction coil can preferably be arranged surrounding the insulating body, in particular to be wound around this. The inductor may also comprise a plurality of coil elements, e.g. embedded in or applied to the insulating body by means of a 3D printing process. This is advantageous, in particular, for the case where the insulating body, which is preferably made of a ceramic material, is produced by a generative manufacturing method. In addition, the generative manufacturing process also makes it possible to design the openings as specifically designed cooling channels. For the supply of the filament to the extrusion die, a material feed body is provided according to a preferred embodiment, one with the extrusion of the
    Extrusion nozzle has aligned supply channel. The Materialzuführkörper is not heated directly here. The feed channel is not used for extrusion, but merely for feeding the filament to the extrusion die, so that the feed channel can preferably be cylindrical.
    The extrusion channel of the extrusion die, on the other hand, is preferably formed with a cross section which reduces in the material exit direction. By way of example, the extrusion channel can have a conically tapered configuration, wherein a continuous cross-sectional constriction is preferably provided.
    Different filament materials result in different demands on the extrusion die, in particular on the geometry of the extrusion channel and on the adjustment of the temperature conditions in the extrusion die. Filament materials differ in particular in their melting behavior. The extrusion die is therefore preferably adapted to the respective extrusion material. The inherent thermal conductivity coefficient of the material determines to what extent the temperature may be passed from the heated inner edge of the extrusion die. The geometry should be specially adapted to the material properties of the extrusion material intended for processing. This significantly improves the extrusion process. The processing becomes significantly lighter, so that e.g. the force for the advance of the
    Extrusion material decreases and the introduced into the system energy can be reduced. Due to the short processing time, the degradation of the polymer chains is reduced and a higher quality material is extruded overall.
    A simple adaptation of the extrusion die to the respective extrusion material succeeds according to a preferred embodiment in that the extrusion die is detachably connected to the material feed body, wherein the extrusion die is connected to the material feed body either directly or through the intermediary of another component, in particular the insulating body. Thereby a plurality of extrusion nozzles with different properties, e.g. be kept in stock with different geometry of the extrusion channel, and in a material change and the extrusion die can be replaced. The releasable connection of the extrusion die is preferably carried out by means of a threaded connection. The extrusion die can be screwed directly to the Materialzuführkörper. Alternatively, an indirect connection of the extrusion die to the material supply body may be provided, whereby a further component, such as e.g. the insulating body, is provided, which is in communication with the Materialzuführkörper and with which the extrusion die is detachably connected.
    A preferred possibility for influencing the geometry and / or the heating and / or the sliding properties and / or the wear characteristics of the extrusion channel is that the channel wall of the extrusion channel of the extrusion die of at least one
    Material layer is formed of a different material from the nozzle body of the extrusion die material. The material layer is arranged so that it is in contact with the extruded material forced through the extrusion channel. In the case of a multilayer construction with two or more material layers, it is provided that only the innermost layer is in contact with the extrusion material pressed through the extrusion channel.
    Advantageously, the at least one layer of material is formed as a sleeve, which is received in the nozzle body and limits the extrusion channel. This enables the manufacture of the sleeve in a separate manufacturing step from the nozzle body, the nozzle body e.g. is made as a body with a constant geometry and the adaptation of the extrusion channel geometry is done only by the design of the sleeve. Alternatively, the material layer by a
    Coating process can be applied.
    Alternatively, the sleeve itself may be formed as an extrusion die, i. a nozzle body as a carrier of the sleeve can be omitted. The sleeve formed as an extrusion nozzle can be constructed in multiple layers.
    The material of the at least one layer of material may be selected depending on the desired function. According to a preferred embodiment, the material layer consists of the inductively heatable material, so that the heat energy arises directly on the channel wall of the extrusion channel.
    Alternatively, the nozzle body may consist of the inductively heatable material and a coating consists of a non-inductively heatable material.
    Furthermore, it can be provided that the material layer consists of a ceramic material or polycrystalline diamond. As a result, the wear resistance of the extrusion channel can be substantially increased.
    The following configurations of the extrusion die can be premature:
    The nozzle body consists of an inductively heatable material and has on the inside a conical geometry, in which a sleeve is used with an optimized for the filament melt material geometry of the extrusion channel.
    Alternatively, the nozzle body may be made of a material that is not inductively heatable, but one on the plastic melt, in particular
    Filamentmaterialschmelze, optimized geometry on the inside holds on which a layer of inductively heatable material is arranged. The layer of the inductively heatable material is preferably applied by means of a coating method.
    Alternatively, the nozzle body consists of an inductively heatable material and provides on the inside a geometry optimized for the filament melt, to which a non-inductively heatable surface is applied by means of a coating method.
    Alternatively, the channel wall of the extrusion channel is formed by a sleeve which consists of a non-inductively heatable material and on the inside provides a geometry optimized for the filament material melt. On the outside, an inductively heatable surface is preferably applied by means of a coating method or a deep-drawing method.
    Alternatively, the channel wall of the extrusion channel is formed by a sleeve which consists of a non-inductively heatable material and on the inside provides a geometry optimized for the filament material melt. On the outside, the sleeve is cone-shaped, wherein the cone is used to connect the sleeve with a nozzle body made of an inductively heatable material.
    According to a further aspect, the invention relates to a modular system for the layered application of material for the generative production of a molded article comprising an extrusion head according to the invention, in particular a print head having a replaceable first extrusion die, and further comprising at least one second extrusion die, the first and the second extrusion die each having an extrusion channel having a tapered in the exit direction of the material cross-section, wherein the extrusion channel of the first and the second extrusion die has a mutually different geometry.
    According to a further aspect, the invention relates to a device for the generative production of a molded article comprising a build platform, at least one extrusion head according to the invention, in particular print head or a modular system according to the invention for the layered application of material onto the build platform or on the build platform at least partially constructed moldings, a positionable Carrier for the at least one extrusion head, a positioning system for the carrier and a feed device for feeding material from a supply of material to the at least one extrusion head.
    Preferably, the construction platform is rigid or merely height-adjustable, and the extrusion head, which is preferably exchangeably received in a support, in particular a print head, is provided with the aid of a
    Positioning system two-dimensional in one plane or three-dimensional positionable or movable in space.
    The positioning system distinguishes between a Cartesian system and a so-called "Delta" system. In Cartesian principle, the positioning of the carrier is carried out by means of three driven linear axes, which span the three-dimensional space with the coordinate axes x, y and z. The delta printer uses the principle of parallelogram kinematics and can be programmed so that the carrier accommodating the print head can be moved. A three-dimensional positioning is realized here by the method of three driven, triangular spanning axes in the vertical direction, which hold the carrier.
    The invention will be explained in more detail with reference to embodiments shown schematically in the drawing. 1 shows an external view of a 3D printer, FIG. 2 shows a plan view of the 3D printer according to FIG
    1, 3 a first interior view of the 3D printer,
    4 shows a view of FIG. 4 with a printhead embedded in the printing chamber, FIG. 6 shows a printhead according to the invention in a sectional view, FIG. 7 shows the extrusion nozzle of the printhead according to FIG. 6, FIG 8 shows the production of a sleeve for forming the extrusion channel of an extrusion die and FIG. 9 shows a modified embodiment of the printing head.
    In Fig. 1, a 3D printer 1 is shown. The 3D printer has a main housing 2, which is provided on at least one side surface with a viewing window 3, which releases an insight into the installation space 4 of the 3D printer 1. In the installation space 4 of the 3D printer 1, a carrier 5 is held in a positionally adjustable position by means of a positioning system. The carrier 5 carries printheads 6, which are designed for dispensing a production material.
    The 3D printer 1 further includes a laterally on
    Main housing 2 arranged additional housing 7, which has at least one, preferably three receiving or insertion slots for interchangeable inserts.
    In plan view of FIG. 2 it can be seen that the
    Main housing 2 has a triangular outline, wherein the additional housing 7 is arranged laterally of the main housing 2 and has three receiving or insertion slots 15 for interchangeable inserts 16. The respective replaceable insert 16 can be inserted or inserted in the direction of the arrow 42 in the respective receiving or insertion slot 15.
    In the interior view of FIG. 3 is now the
    Positioning system for the carrier 5 shown in more detail. The positioning system comprises three vertical guides, e.g. Guide rods 8, of which in Fig. 3, two guide rods 8 are visible. On the guide rods 8, a carriage 9 is arranged in each case movable in the vertical direction, wherein the drive comprises a schematically indicated toothed belt 10 which is driven in each case by a stepping motor 11. The carrier 5 is fastened to the carriage 9 by means of holding rods 12 hinged on both sides. The slides 9 are independently adjustable in the direction of the arrow 13, whereby a three-dimensional positioning of the carrier 5 in the space 4 is made possible. Inside the installation space 4 there is a construction platform 14 on which the shaped body to be formed is built up in layers by material application from the printing heads 6.
    In Fig. 3 is further seen that the laterally mounted additional housing 7 has two slots 15, each receiving a replaceable insert 16. The replaceable inserts 16 are open to the space 4, so that the carrier 5 can be loaded from the interchangeable inserts 16 with printheads. The interchangeable inserts 16 each have a housing, wherein in the interchangeable insert 16 arranged farther back in FIG. 3, a rear and a front housing wall 18 can be seen. In the interchangeable insert 16 arranged further in FIG. 3, only the rear housing wall 19 can be seen. The front housing wall is not shown for clarity, so that the recorded in the interchangeable insert 16 components are better visible. If necessary, a dividing wall 17 can be provided between the housings of the interchangeable inserts 16, which separates the two insertion spaces 15 from one another.
    The removable inserts 16 include a
    Material receptacle in the form of a roll of material 20, which has a coil-like wound, strand-like material (filament). The material roll 20 is associated with a feed device 21, which is designed to remove the filament from the roll 20 and supply the print head 6. The print head 6 is held in a holding device 22 which is mounted on an arm 23 consisting of several segments.
    FIG. 4 shows the same 3D printer as FIG. 3 in an interior view, wherein a perspective different from FIG. 3 is shown. While the print head 6 held in the retainer 22 in FIG. 4 is in a storage position, i. is arranged in the interchangeable insert 16, this was displaced in the representation of FIG. 5 in the projecting into the space 4 transfer position. The displacement takes place here by the pivoting of the arm 23 to which the holding device 22 is attached. The transfer position of the printhead 6 shown in FIG. 5 enables a transfer of the printhead 6 from the holding device 22 into a printhead receptacle of the carrier 5. The carrier 5 can be moved up to the printhead held in the holding device 22 for this purpose so that the printhead 6 is inserted into the printhead receptacle of the carrier 5. The holding device 22 is formed so that it is also capable of one in the
    Carrier 5 recorded printhead after completion of the intended manufacturing steps and to move from the transfer position back to the storage position shown in Fig. 4.
    In Fig. 6, a print head 6 is shown in a sectional view, wherein the print head can be used in a device according to FIGS. 1-5 or in a differently constructed 3D printer. The printhead comprises a material feed body 24 with a feed channel 25. In the lower region of the material feed body 24, an external thread is formed onto which an insulation body 26 can be screwed, which in turn carries an extrusion die 27 which has an extrusion channel 28 which is aligned with the feed channel 25 , The
    Insulating body 26 surrounding an induction coil 29 is provided, which is designed for inductive heating of an inductively heatable material of the extrusion die 27. The extrusion die 27 is by means of a
    Screw connected to the insulating body 26.
    In Fig. 7, the extrusion die 27 of the printing head 6 shown in Fig. 6 is more apparent. The
    Extrusion die 27 comprises a nozzle body 35 and one or more material layer or material layers 30 bounding the extrusion channel 28, which e.g. may be formed as a separately prepared sleeve or was applied by means of a coating method on the inside of the nozzle body.
    In Fig. 8, a preferred manufacturing method for producing a nozzle channel 28 limiting sleeve is shown, wherein the sleeve consists of three layers 32, 33 and 34 which are formed of mutually different materials. A temporary carrier 31 is provided which is first provided with the layer 32. Thereafter, the layer 33 is applied over the layer 32 and finally the layer 34 is applied over the layer 33. After removal of the carrier 31 is a three-layer sleeve available, which can be accommodated in a nozzle body. The carrier 31 can be both a reusable mold and a destructible in the manufacturing process form.
    In the embodiment of Fig. 9, a sleeve, such as e.g. the sleeve of FIG. 8, used directly as an extrusion die. The extrusion die 27 is of the
    Isolation body 26 held or bordered, the finger-like holding elements 35 includes, which engage the tapered front portion of the extrusion die 27. Between the finger-like holding elements 35 remain openings, through which a cavity 36 of the insulating body 26 is in communication with the environment. The insulating body 26 is held on the outer jacket of the material supply body 24.
    权利要求:
    Claims (13)
    [1]
    Claims:
    1. extrusion head, in particular print head for the layered application of material for the generative production of a shaped body comprising an extrusion die with an extrusion channel and a heater for melting the polymer material supplied to the extrusion die, characterized in that the heating device is designed as an inductive heating, which has a comprising the extrusion nozzle surrounding inductor, wherein the extrusion nozzle consists at least partially of an inductively heatable material.
    [2]
    2. Extrusion head according to claim 1, characterized in that the extrusion die is held for a thermal and possibly electrical insulation in a surrounding these insulating body, which preferably consists of a ceramic material.
    [3]
    3. extrusion head according to claim 2, characterized in that the insulating body has an annular cross-section and optionally has axial openings.
    [4]
    Extrusion head according to claim 2 or 3, characterized in that the inductor, e.g. at least one induction coil is arranged in or on the insulating body.
    [5]
    5. extrusion head according to one of claims 1 to 4, characterized in that a Materialzuführkörper is provided which has a aligned with the extrusion channel of the extrusion nozzle feed channel.
    [6]
    6. extrusion head according to claim 5, characterized in that the extrusion nozzle is detachably connected to the Materialzuführkörper, wherein the extrusion die is connected either directly or through the intermediary of another component, such as in particular of the insulating body, with the Materialzuführkörper.
    [7]
    7. extrusion head according to one of claims 1 to 6, characterized in that the channel wall of the extrusion channel of the extrusion die is formed by at least one material layer of a material different from the material of the nozzle body of the extrusion die.
    [8]
    8. extrusion head according to claim 7, characterized in that the at least one layer of material is formed as a sleeve which is received in the nozzle body and limits the extrusion channel.
    [9]
    9. extrusion head according to claim 7 or 8, characterized in that the material layer consists of the inductively heatable material.
    [10]
    10. extrusion head according to claim 7 or 8, characterized in that the material layer consists of a ceramic material or of polycrystalline diamond.
    [11]
    11. Extrusion head according to claim 7, 8 or 10, characterized in that the nozzle body consists of an inductively heatable material.
    [12]
    12. Modular system for the layered application of material for the generative production of a molded article comprising an extrusion head, in particular print head according to one of claims 1 to 11, having a replaceable first extrusion die, and further comprising at least one second extrusion die, wherein the first and the second extrusion die each having an extrusion channel having a tapered in the exit direction of the material cross-section, wherein the extrusion channel of the first and the second extrusion die has a mutually different geometry.
    [13]
    13. A device for the generative production of a molded article comprising a build platform, at least one extrusion head, in particular print head according to one of claims 1 to 11 or a modular system according to claim 12 for the layered application of material to the build platform or on the build platform at least partially constructed moldings, a positionable carrier for the at least one extrusion head, a carrier positioning system, and feeding means for feeding material from a supply of material to the at least one extrusion head.
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    同族专利:
    公开号 | 公开日
    EP3554797A1|2019-10-23|
    AT520657B1|2021-03-15|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    US20150183167A1|2013-12-31|2015-07-02|Nike, Inc.|3d printer with native spherical control|
    WO2017084500A1|2015-11-17|2017-05-26|李乾勇|Induction heater and 3d printer/extruder|
    US20170312849A1|2016-05-02|2017-11-02|Electronics And Telecommunications Research Institute|Extruder for metal material and 3d printer using the same|
    CN113263721A|2021-06-09|2021-08-17|河北大学|Three-nozzle layered collaborative printing method and three-nozzle 3D printer|
    法律状态:
    优先权:
    申请号 | 申请日 | 专利标题
    AT601362017|2017-12-05|EP18818973.2A| EP3554797A1|2017-12-05|2018-11-29|Printhead for the layer-by-layer application of material|
    PCT/AT2018/000094| WO2019109114A1|2017-12-05|2018-11-29|Printhead for the layer-by-layer application of material|
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