• 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:
    Control and / or regulating device (1) for controlling and / or regulating an injection screw (2) of an injection molding machine (3), at least comprising a control and / or regulating unit (4) for controlling and / or regulating the pressure (p) and or the speed (q) of the injection screw (2), and a pressure estimator (5) for estimating a pressure (p ') of the injection screw (2), wherein a load estimator (6) for estimating a load (k') counteracting the injection screw is provided, by the load estimator (6) the estimated load (k ') at least to the control and / or regulating unit (4) can be reported.
    公开号:AT510879A1
    申请号:T21442010
    申请日:2010-12-27
    公开日:2012-07-15
    发明作者:Kurt Dipl Ing Dr Techn Schlacher；Harald Dipl Ing Daxberger；Hannes Dipl Ing Bernhard
    申请人:Engel Austria Gmbh；
    IPC主号:
    专利说明:

    1
    The invention relates to a control and / or regulating device for controlling and / or regulating an injection screw of an injection molding machine, at least comprising a control and / or regulating unit for controlling and / or regulating the pressure and / or the speed of the injection screw, and a pressure estimator for Estimate a pressure of the injection screw.
    In an injection molding process, plastic granules are usually supplied to an injection screw of an injection molding machine. The injection screw is located in a worm cylinder and the plastic granules are conveyed by a rotational movement of the injection screw towards the tip of the injection screw in a corresponding antechamber of the worm cylinder. By friction and a corresponding heating device, the plastic granules are melted into a plastic melt. This plastic melt collects in front of the tip of the injection screw in the antechamber of the screw cylinder. If there is enough plastic melt for an injection process in the vestibule, the injection screw is pushed in the manner of a piston forward toward the tip of the injection screw, whereby the plastic melt can be injected into a corresponding shape. Such a shape is also referred to as a mold or cavity and may for example consist of two mold parts, which are closed before the injection process.
    The rotational movement and the forward movement of the injection screw can be achieved for example via electrical or hydraulic drives. These drives can be controlled or regulated via a corresponding control and / or regulating device, wherein this control and / or regulating device may have a speed and / or position and / or pressure control. The speed of the forward movement of the injection screw along the injection axis (injection speed) is typically controlled so that a certain pressure of the now acting as a piston injection screw on the plastic melt is not exceeded. The pressure, which is also referred to as the injection pressure, can result from the force which acts on the injection screw by the drive to carry out its forward movement. During the entire injection molding process, the injection screw counteracts a so-called load, which corresponds to the current filling resistance or a conductance of the flow path into the cavity. The load depends, among other things, on the shape or geometries used along the flow path, the viscosity of the plastic melt during the 68698 30 / hn 2
    Injection and other factors such. Temperatures along the flow path from.
    After the mold has been completely filled with the plastic melt by the forward movement of the injection screw, there is a rapid increase in pressure in the mold, which is influenced inter alia by the compressibility of the plastic melt. Upon detection of this rapid increase in pressure is typically switched by a speed control of the injection screw to a pressure control. This first control phase, in which the speed of the injection screw is controlled during the injection phase, is often referred to as volume flow control, since the speed of the forward movement of the injection screw corresponds to a corresponding volume flow of the plastic melt in the screw cylinder. The second phase of the scheme, in which mainly the pressure of the injection screw on the
    Plastic melt is regulated, is often referred to as a holding pressure phase. This post-pressure phase is particularly important because the volume can be correspondingly reduced by the cooling of the plastic melt in the mold and plastic melt can continue to be pressed into the mold as a result of this holding pressure phase.
    In an injection molding process, it should be at a switching of a
    Speed control to a pressure control as possible to avoid any pressure drops or pressure peaks, as these can adversely affect the quality of the produced injection-molded parts. Therefore, pressure estimators can be used to estimate occurring pressures and thus allow a more accurate switching (see for example DE 10 2004 051 109 B4). However, conventional pressure estimators have no information regarding the form or material used for the plastic melt. In particular, they also have no information regarding the Lastverhaitens, which results mainly from the shape and the material of the plastic melt. Regardless of shape and material, however, it is desirable that the speed and / or pressure curve of an injection molding process, often referred to as a shot, each follow a desired desired course. Current controllers often employ methods that implicitly make assumptions for the system to implement dynamic controls. However, if deviations from the assumed system behavior occur, in some cases large setpoint deviations or inharmonic signal curves of pressure and speed occur. 3
    The object of the invention is to avoid the disadvantages described above and to provide a comparison with the prior art improved control and / or regulating device for controlling and / or regulating an injection screw of an injection molding machine. A goal is a control and / or regulating device, which can regulate both the speed and the pressure of an injection screw and in particular can adjust the occurring load change during the transition from the speed control to the pressure control accordingly.
    This object is achieved according to the invention by providing a load estimator for estimating a load counteracting the injection screw, wherein the estimated load can be reported to the control and / or regulating unit by the load estimator. In principle, the control and / or regulating unit can comprise at least one pilot control and one controller, and the estimated load can relate to the current load and / or a future load.
    The load is mainly determined by the shape and material of the plastic melt. In particular, the shape can vary greatly due to the application. This will also behave differently depending on the application. This variable influence is to be determined with the load estimator, with which the control and / or regulating unit can be adapted to the current system behavior.
    The load estimator can be used to detect a change in load at an early stage. Estimating the current and / or future load counteracting the load can be done on the basis of a model. By this additional information - the estimated load arrest - the pressure caused by the injection screw, for example, may be reduced soon enough to avoid pressure spikes. Due to the estimated load, regardless of the point in time and the state when switching from the injection phase to the holding pressure phase, an overflow-free course of the pressure of the injection screw can be realized. In this case, good follow-up behavior can be achieved in the dynamic transition from the speed-controlled injection into the holding pressure range by the load estimator detecting the rapidly changing load and, for example, compensating for this influence independently of the current operating point by means of precontrol.
    The estimated load can be represented by an estimated resistance coefficient k '. This estimated resistance coefficient k 'corresponds to the estimated resistance 4 of the filling process, which is significantly influenced by the configuration of the shape or the geometries along the flow path of the plastic melt and by the material used for the plastic melt. For example, the resistance of the filling process is higher, the longer the flow path for the plastic melt and the higher the viscosity of the plastic melt.
    In order to determine the estimated drag coefficient k ', a simplified load model can be used which, among other things, incorporates the following parameters: cross-sectional area of the worm cylinder, mass moment of inertia of the drive, compressibility and volume and viscosity of the plastic melt. The compressibility of the plastic melt can be assumed to be known due to material data or metrologically determined.
    With the load model, a relationship between injection speed, injection pressure and control variable can be established. By the load estimator, the generally unknown and application dependent model parameters or model sizes can be determined at any time and the current and / or future load estimated. By knowing the estimated load, the manipulated variable can be calculated by means of a precontrol with a corresponding setpoint specification. In an ideal model, this would follow the actual size of the target size and no deviations would occur. Due to the fact that the model is only a simplification of the real system and the estimated load may deviate from the actual load, small deviations between setpoint and actual value generally occur. These deviations can be compensated by the additional controller. The knowledge of the estimated load represents a significant improvement over conventional controllers without load estimator or without model information, which can only change the manipulated variable due to control errors.
    The load model! can be used in the load estimator, for example, to continuously determine the current load during an injection molding process. This type of load estimator is referred to as an online estimator. Here, in each injection cycle, the load is continuously re-estimated and used for feedforward control. Since an injection process is a cyclical process, it makes sense to use information from previous injection cycles for the current injection cycle in order to improve the follow-up behavior of the control and / or regulating device. The load estimator can be used as an iterative estimator for this purpose Part of the manipulated variable based on 5 of the manipulated variable of the last injection cycle and its error can be calculated. As a result, the load model underlying the estimation can also be improved from shot to shot. Generally, in a weighted integration, previous input quantities and states can be weighted accordingly into a load estimate. However, the determination of the estimated load or the estimated load curve during an injection molding process can in principle also be carried out by one or more test shots. In this case, corresponding values can be determined in a start-up phase, which values are used in subsequent injection cycles. In general, the least squares method can also be used to determine suitable parameters or regression curves for the load estimator.
    In particular, the following parameters can be used as parameters of the control and / or regulating device: weighting of the speed error, weighting of the pressure error, starting value for the load estimator, influence of the pressure control error on the dynamics of the load estimator, influence of the pressure estimation error on the dynamics of the load estimator and influence of the load estimator Pressure estimation error on the dynamics of the pressure estimator.
    According to a preferred embodiment it can be provided that the estimated pressure can be reported to the load estimator. Moreover, if the estimated load can also be reported to the pressure estimator, this results in optimum synergy effects of the two estimators used. The combination of a load estimator with a pressure estimator results in improved adherence to an independent estimation of the load. Thus, the estimation errors can be reduced and the transient response can be increased. As a consequence, the entire control behavior can be improved. A deviation of the estimated load from the actual load may lead to a deviation of the estimated pressure from the measured pressure. By returning this error, the load estimator can be corrected. Without additional pressure estimator, a deviation of the load estimator from the actual load would only be determined and corrected by a deviation from the target pressure to the actual pressure.
    In order to provide the control and / or regulating device corresponding reference variables, a planning device can be provided, wherein the planning device at least a planned Solldruckverlauf and / or a planned desired speed curve, which are preferably stored in a memory, at least the control and / or Control unit and / or the load estimator can be supplied or are. This planning device is also referred to as trajectory planning and supplies the desired set pressure curve and / or the desired set speed profile during an injection molding process. The input of these desired target curves can be done for example via a user interface and the target curves can be stored in a memory and be read by the control and / or regulating device.
    To improve the control and / or regulating behavior of the control and / or regulating device, a pressure measuring device for measuring the pressure of the injection screw may be provided, the signals of the pressure measuring device of the control and / or regulating unit and / or the pressure estimator and / or the load estimator can be fed. For example, the pressure measuring device can measure the pressure inside the mold,
    In addition, a speed measuring device for measuring the speed of the injection screw may be provided, wherein the signals of the speed measuring device at least the control and / or regulating unit and / or the load estimator and / or the pressure estimator are supplied. The speed of the forward movement of the injection screw along the injection axis corresponds to a certain volume flow of the plastic melt in the screw cylinder.
    Alternatively or additionally, a displacement measuring device may be provided for measuring the distance traveled by the injection screw, wherein the signals of the displacement measuring device can be fed to at least the control and / or regulating unit and / or the load estimator and / or the pressure estimator.
    If the control and / or regulating unit comprises at least one precontrol and one controller, it can be provided that a first manipulated variable, preferably a first force value, can be output by the precontrol, and a second manipulated variable, preferably a second force value, by the controller. Preferably, the first manipulated variable and the second manipulated variable, preferably the first force value and the second force value, can be added to control and / or regulate the pressure and / or the speed of the injection screw. The precontrol can be calculated in such a way that the first manipulated variable corresponds to the desired setpoint pressure profile, which can be predetermined by a corresponding planning device (trajectory planning). Deviations of the actual trajectory from the desired desired pressure curve can be compensated by the controller in the form of a second manipulated variable. The two manipulated variables, which can be, for example, a first force value and a second force value, can be added together and produce a total force value with which the drive of the injection screw is to act on the injection screw in the direction of its forward movement by the desired speed and / or the desired speed Pressure of the injection screw to achieve the plastic melt. This manipulated variable in the form of the total force value can be supplied to a corresponding actuator, such as a motor control and / or regulation, the actuator can control and / or regulate a corresponding drive unit, such as an electric motor, the electric motor can subsequently the injection screw drive so that the injection screw can exert the desired pressure on the plastic melt.
    Protection is also desired for an injection molding machine with a control and / or regulating device according to one of claims 1 to 10.
    In addition, protection is desired for a method for controlling and / or regulating the pressure and / or the speed of an injection screw of an injection molding machine according to claim 12. Advantageous variants of this method are given in the dependent claims.
    The invention will be explained in more detail below with reference to a preferred embodiment with reference to the single FIGURE. 1 shows a schematic block diagram of an exemplary embodiment of the proposed control and / or regulating device 1.
    The control and / or regulating device 1 comprises a control and / or regulating unit 4, which in this example comprises a pilot control 10 and a controller 11. Furthermore, the control and / or regulating device 1 comprises a pressure estimator 5 for estimating the pressure p 'and a load estimator 6 for estimating the load, which in this example is represented by the estimated resistance coefficient k'.
    The precontrol 10 supplies as output a first manipulated variable in the form of a first force value F, and the controller 11 supplies as output a second manipulated variable in the form of a second force value F2. The first force value F, and the second force value P2 are added together and give a manipulated variable in the form of a force value F for an actuator 13. This actuator 13 may for example be an engine control and / or regulation, which a corresponding, the injection screw 2 driving Drive unit 14, for example, one or more electric motors, controls and / or regulates. δ
    Through the injection screw 2, a plastic melt during injection molding in a mold 12 can be introduced. The intended pressure measuring device 8 and the provided speed measuring device 9 measure the current pressure p and the current speed q of the injection screw 2 and can confirm these measured values as controlled variables at least to the control and / or regulating device 1. In the example shown, the measured data of the pressure measuring device 8 and the measured data of the speed measuring device 9 are also supplied to the pressure estimator 5 and the load estimator 6. In addition, it is also possible to provide a displacement measuring device for measuring the distance traveled by the injection screw 2, the measured data of which can be fed to at least the control and / or regulating unit 4 and / or the load estimator 6 and / or the pressure estimator 5.
    As reference values for the control and / or regulating device 1, the desired pressure curve ps and / or the desired speed curve qs (and, where appropriate, their first and second derivatives according to time) are provided, which by a corresponding
    Planning device 7 (trajectory planning) can be specified. The pressure estimator 5 supplies as output the estimated pressure p which can be supplied to the load estimator 6. The load estimator 6 supplies as an output the estimated resistance coefficient k ', which in this example can be fed to both the control and / or regulating unit 4 and the pressure estimator 5.
    The quantities k 'and p' represent outputs of dynamic systems (load estimator 6 and pressure estimator 5) in which, based on a respective initial state and the respective values of the input variables, corresponding follow states and output values are calculated. The dynamic systems are designed so that the load is calculated according to a given load model.
    By the control and / or regulating device 1, the actuator 13 can be controlled and / or regulated so that the actuator 13 controlled and / or regulated drive unit 14 can exert the desired force F on the injection screw 2 in the direction of their forward movement, so that the desired speed q of the injection screw 2 and / or the desired pressure p of the injection screw 2 can be achieved on the plastic melt according to the trajectory planning. θ
    A significant advantage of the proposed control and / or regulating device lies in the combination of a corresponding desired value generation (trajectory planning) with a load estimator and a model-based control with integrated feedforward control. In particular, results in a good follow-up behavior with dynamic setpoint changes in the emphasis area by using the load estimator and the feedforward independent of the current operating point.
    Innsbruck, December 23, 2010
    权利要求:
    Claims (16)
    [1]
    1 claims: 1. Control and / or regulating device (1) for controlling and / or regulating an injection screw (2) of an injection molding machine (3), comprising at least: a control and / or regulating unit (4) for controlling and / or regulating the pressure (p) and / or the speed (q) of the injection screw (2), and a pressure estimator (5) for estimating a pressure (p ') of the injection screw (2), characterized in that a load estimator (6) for estimating one of the injection screw counteracting load (k ') is provided, wherein by the load estimator (6) the estimated load (k) at least to the control and / or regulating unit (4) can be reported.
    [2]
    2 control and / or regulating device according to claim 1, characterized in that the estimated pressure (p ') to the load estimator (6) is notified.
    [3]
    3 pressure (ρ1) and an estimated load (k ') are controlled and / or regulated.
    3. Control and / or regulating device according to claim 1 or 2, characterized in that the estimated load (k ') also to the pressure estimator (5) can be reported.
    [4]
    4. Control and / or regulating device according to one of claims 1 to 3, characterized in that a planning device (7) is provided, wherein the planning device (7) a planned desired pressure curve (ps) and / or a planned target speed curve (q3) , which are preferably stored in a memory, at least the control and / or regulating unit (4) and / or the load estimator (6) can be fed or are.
    [5]
    5. Control and / or regulating device according to one of claims 1 to 4, characterized in that a pressure measuring device (8) for measuring the pressure (p) of the injection screw (2) is provided, wherein the signals of the pressure measuring device (8) of the control - And / or control unit (4) and / or the pressure estimator (5) and / or the load estimator (6) can be fed. 68698 30 / hn 2
    [6]
    6. Control and / or regulating device according to one of claims 1 to 5, characterized in that a speed measuring device (9) for measuring the speed (q) of the injection screw (2) is provided, wherein the signals of the speed measuring device (9) at least the Control and / or regulating unit (4) and / or the load estimator (6) and / or the pressure estimator (5) can be fed.
    [7]
    7. Control and / or regulating device according to one of claims 1 to 6, characterized in that a displacement measuring device for measuring the distance covered by the injection screw (2) is provided, wherein the signals of the displacement measuring device at least the control and / or regulating unit (4 ) and / or the load estimator (6) and / or the pressure estimator (5) can be fed.
    [8]
    8. Control and / or regulating device according to one of claims 1 to 7, characterized in that the control and / or regulating unit (4) comprises at least one feedforward control (10) and a controller (11).
    [9]
    9. Control and / or regulating device according to claim 8, characterized in that by the feedforward control (10) a first manipulated variable, preferably a first force value (Fj), and by the controller (11) a second manipulated variable, preferably a second force value ( F2), can be output.
    [10]
    10. Control and / or regulating device according to claim 9, characterized in that for controlling and / or regulating the pressure (p) and / or the speed (q) of the injection screw (2), the first manipulated variable and the second manipulated variable, preferably the first force value (F,) and the second force value (F2), are added,
    [11]
    11. Injection molding machine with a control and / or regulating device according to one of claims 1 to 10.
    [12]
    12. Method for controlling and / or regulating the pressure (p) and / or the speed (q) of an injection screw (2) of an injection molding machine (3), wherein in an injection molding process by the injection screw (2) a plastic melt into a mold (12 ), wherein this injection molding process counteracts a load, characterized in that the pressure (p) and / or the speed (q) of the injection screw (2) in dependence of an estimated Μ ·· · · · · · · ·
    [13]
    13. The method according to claim 12, characterized in that as a reference variable for controlling and / or regulating the pressure (p) and / or the speed (q) of the injection screw (2) a planned desired pressure curve (pa) and / or a planned target speed curve ( qs) is or will be used.
    [14]
    14. The method according to claim 13, characterized in that for estimating the load (k ') at least the planned desired pressure curve (ps) and / or the current pressure (p) and / or the estimated pressure (p') and / or the planned Set speed course (qs) and / or the current speed (q) is / are used.
    [15]
    15. The method according to any one of claims 12 to 14, characterized in that for estimating the pressure (p ') at least the current pressure (p) of the injection screw (2) and / or the current speed (q) of the injection screw (2) and / or the estimated load (k ') is or will be used.
    [16]
    16. The method according to any one of claims 12 to 15, characterized in that as a control variable for controlling and / or regulating the pressure (p) and / or the speed (q) of the injection screw (2) a force (F) is determined, with the injection screw (2) is urged in the direction of forward movement of the injection screw (2) in order to press the plastic melt into the mold (12). Innsbruck, December 23, 2010
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    同族专利:
    公开号 | 公开日
    CN102529054A|2012-07-04|
    AT510879B1|2012-10-15|
    CN102529054B|2015-01-21|
    DE102011116868A1|2012-06-28|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    JP2006142659A|2004-11-19|2006-06-08|Niigata Machine Techno Co Ltd|Pressure controller using servomotor|
    JP2006256067A|2005-03-16|2006-09-28|Ube Machinery Corporation Ltd|Method and apparatus for controlling pressure of electric injection molding machine|
    CN1082879C|1993-10-27|2002-04-17|普罗控制公开股份有限公司|Servo-gearshift, method and turning means used in die casting machine|
    JP3404652B2|2000-04-04|2003-05-12|住友重機械工業株式会社|Filling process control method and control device for injection molding machine|
    US6682669B2|2001-09-29|2004-01-27|Van Dorn Demag Corporation|Model predictive control apparatus and methods for motion and/or pressure control of injection molding machines|
    DE102004051109B4|2004-10-19|2007-01-18|Siemens Ag|Method for operating an injection molding machine|
    JP2006142369A|2004-11-24|2006-06-08|Ykk Corp|Motor-driven injection unit, die-casting machine equipped with the same and motor-driven injection method|
    JP4410816B2|2007-10-02|2010-02-03|日精樹脂工業株式会社|Control device for injection molding machine|AT514232B1|2013-04-18|2015-04-15|Engel Austria Gmbh|Method for controlling or regulating an injection molding machine|
    AT516879B1|2015-02-16|2018-02-15|Engel Austria Gmbh|Method for operating an injection unit and injection unit|
    法律状态:
    优先权:
    申请号 | 申请日 | 专利标题
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    DE201110116868| DE102011116868A1|2010-12-27|2011-10-25|Device for controlling and regulating injection screw of injection molding machine, has load estimator that is provided for estimating counteracting load of injection screw|
    CN201110400524.6A| CN102529054B|2010-12-27|2011-12-06|Control and / or regulation device for controlling and / or regulating injection worm of die casting machine|
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