DE102013016914A1 - Method for simulating injection molding process of injection molding machine, involves notifying parameters of process simulation unit for entering parameters of machine simulation unit corresponding to input mask of machine - Google Patents

Abstract

The method involves calculating volumetric flow (V-) parameter of a physical model in a machine simulation unit (MS) for simulating an injection molding machine (2). The to-be-processed molding material is simulated for calculating the pressure parameter (p) of to-be-processed molding material in a process simulation unit (PS). The parameter calculated in the process simulation unit is notified through an interface (12) for entering the parameters calculated in the machine simulation unit corresponding to an input mask (11) of the injection molding machine. Independent claims are included for the following: (1) simulating device for injection molding process of injection molding machine; and (2) injection molding machine.

Description

The present invention relates to a method for simulating an injection molding process with the features of the preamble of claim 1, a simulation device for simulating an injection molding process with the features of the preamble of claim 13 and an injection molding machine with such a simulation device.

It is known to simulate injection molding machines, wherein in particular the machine movements are calculated according to the set cycle sequence and the behavior of the drive components. Software of this type serves primarily the training of operators for injection molding machines and the testing of machine software.

Furthermore, process simulations are known in which the injection molding tool is modeled as a 3D model, and the molding process is simulated beginning with the inflow of the melt, the Nachdruckphase and the cooling down to demoulding of the finished part. For a given geometry of a cavity pressure and temperature can then be calculated in the process simulation for each time of the injection molding process. It is therefore attempted to predict the finished product of the injection molding process, with about shrinkage and distortion is taken into account. The behavior of the injection molding machine itself must be largely ignored in these simulations, the software takes into account only some basic data of the injection molding machine, such as screw diameter, maximum injection speed, maximum injection pressure or maximum closing force. However, since the precise injection behavior, and also the closing behavior during injection compression, has a great influence on the end product of the injection molding process, the accuracy of these process simulations can be improved.

The object of the invention is to provide a method and a device for simulating an injection molding process, which enables the prediction of the finished product with an accuracy which comes closer to the permitted tolerances of the finished product.

This object is achieved by a method having the features of claim 1, by a simulation device having the features of claim 13, and by an injection molding machine having such a simulation device.

This is done by simultaneously performing a machine simulation and a process simulation, wherein the process simulation of at least one first parameter calculated by the machine simulation - preferably at least one volume flow - is made available and / or the machine simulation of at least one second parameter calculated by the process simulation at least one pressure in the cavity - is provided. In other words, all elements essential to the result of the injection molding process are simulated and the results of the simulations exchanged.

It is standard to perform simulations step by step - ie to discretize the time. Of course, it is also preferably provided in the present invention to exchange the pressure and the volumetric flow and optionally further parameters after each simulation step.

By improving the accuracy of the simulation achieved by the invention, there are numerous advantages in the manufacture of injection molded parts. By accurately predicting the final product of the injection molding process, it is possible to estimate in advance, for example, the energy requirement during production or the cycle time and thus the expected productivity. The selection of the injection molding machine for a part to be produced can be carried out more reliably due to simulations according to the invention than is possible with process simulations of the prior art. The results of the simulations can also be used with the accuracy achieved to identify the responsible components in case of problems. These can then be exchanged accurately, without having to proceed with the problem-solving according to the trial-error principle.

It is preferably provided to simulate the injection molding material together with the injection mold. In this case, the injection mold is to be represented in the process simulation and not in the machine simulation.

Further embodiments of the invention are defined in the dependent claims.

In order to optimally detect the thermal situation in the injection molding tool, at least one temperature of an injection mold to be simulated can be calculated in the machine simulation and / or in the process simulation and the at least one temperature of the process simulation and / or the machine simulation can be communicated. Preferably provided here is an embodiment in which the behavior of the tool heating controller is simulated by the machine simulation.

It can be provided that in the machine simulation at least one position and / or at least one speed to is simulated moving platen and that the at least one position and / or the at least one speed of the process simulation is communicated. Likewise, it can be provided that in the machine simulation at least one force is calculated on a mold clamping plate to be simulated and that the at least one force is communicated to the process simulation. Through these measures, the simulation can also be used for the injection-compression molding process.

For a particularly accurate return of the results of the process simulation for machine simulation, at least one Auftreibkraft which is affected by the material to be simulated injection molding, and at least one Auftreibkraft the machine simulation can be communicated in the process simulation.

To perform calculations of volume flows as accurately as possible, it may be provided in the process simulation to simulate the behavior of the injection molding material in a machine nozzle and preferably in a screw antechamber.

It can also be provided that the plasticizing process is simulated in the process simulation or in the machine simulation. The results are, for example, the plasticizing performance and / or a temperature distribution and / or a pressure distribution of the molten injection molding material.

It is furthermore preferably provided that in the machine simulation and / or in the process simulation at least one deformation of a part - in particular of an injection molding tool - of an injection molding machine to be simulated is calculated and that the at least one deformation of the process simulation and / or the machine simulation is reported. By taking into account the deformation of the entire system, consisting of machine, tool and molded part, the effects of tool breathing and shrinkage can be recorded true to the original.

Also preferred is an embodiment in which components of the injection molding machine and / or components of the injection molding tool are reproduced in the machine simulation by exchangeable component simulations. This allows a quick adaptation of the simulation by the user.

In order to create an adjustment data set for an injection molding machine, at least one simulation according to the invention can be carried out and based on the results of the adjustment data set can be created. It is advantageous to carry out several simulations according to the invention with different sets of initial parameters and then to select the set of initial parameters which has produced the best result. In this case, an automated optimization can be carried out specifically, that is, defined input parameters are varied within predetermined limits until certain target variables have reached a desired value. Input parameters may be the setpoint values that can be set on the machine, but also geometrical data of tool or machine components, material data of the injection molding material or the materials occurring in the machine or in the tool. As target variables, preference is given to defining quality characteristics of the component and / or parameters which influence the productivity of the process (cycle time, energy consumption).

In this sense, it may be advantageous for experimental plans to be executed automatically, with several simulations according to the invention being carried out with varying initial parameters.

For reasons of simple operation or for the training of operating personnel, an interface of the machine simulation for inputting parameters can correspond to an input mask of the injection molding machine.

Protection is also desired for an injection molding machine with a simulation device according to the invention, wherein the simulation device is connected to a control or regulating device of the injection molding machine.

It is preferably provided here that user-definable parameters of the machine simulation can be taken over by the control or regulating device of the injection molding machine as an adjustment data record. This eliminates the need for manual input of parameters for the injection molding process by the operator.

Software products for calculating the melting process of plastic granules in screw plasticizing units are available on the market. In addition to material data and the process parameters relevant for plasticizing, these also require the geometric data of the screw. Calculation results include the time course of the plasticizing capacity, the required worm torque and the temperature and pressure distribution in the melt. It can be provided to couple such calculation programs with the virtual machine and / or with the process simulation via suitable interfaces. Again, the input screens of the machine simulation in the simplest case again for the parameterization of plasticizing simulation be used. Preferably, an iterative coupling can be performed: The machine simulation specifies a screw speed for a first time step. The plasticizing simulation calculates, among other things, the plasticizing capacity and the required moment and returns it to the machine simulation. The plasticizing capacity corresponds to the quantity of material plasticized per time. Since this material is conveyed into the auger, the auger moves backwards, a new auger position can be calculated. The required torque, in accordance with the control behavior of the machine, in turn leads to a new speed, which is passed to the plasticizing simulation as the default for the second time step. The loop is repeated until the screw has reached the set metering stroke. The results of this coupled simulation are a realistic dosing time and a temperature distribution in the melt, which can be incorporated into the other calculations described.

Further advantages and details of the invention will become apparent from the figures and the associated description of the figures. Show

1 an injection molding machine with a simulation device according to the invention and

2 a flowchart of a simulation method according to the invention.

In 1 is the injection molding machine 2 and schematically its control unit 3 and the simulation device 1 displayed. Here is an example of a vertically closing clamping unit with bars 4 , a fixed platen 5 and a movable platen 6 shown. Of course, the invention can also be used for any other type of closing units. The control or control unit 3 is usually with all the essential elements of the injection molding machine 2 connected. Exemplary here are connections with the rapid traverse cylinders 13 , the locking mechanisms 7 , the printing mechanisms 8th and the injection unit 9 shown.

The closing unit is shown here in the open state, whereby a mold half of the injection mold 10 is visible.

In the simulation device 1 A machine simulation MS and a process simulation PS run, wherein in each simulation step, a pressure p calculated by the process simulation PS is forwarded to the machine simulation MS. Furthermore, at each process step the machine simulation MS calculates the volume flow V calculated by it. passed on to the process simulation PS. In addition, the following quantities are simulated and exchanged by the machine simulation MS or the process simulation PS: A temperature T of the injection molding tool, one on the mold clamping plate 6 acting force F, a force exerted by the melt Auftreibkraft F _A , a position x and a speed v of the movable platen 6 and a deformation Δx of the injection mold. The temperature T, the force F Auftreibkraft F _A and the deformation Ax may be present as spatially resolved sizes, which means it can actually for all spatial coordinates that are relevant for the respective sizes, a temperature T, a force F, a Auftreibkraft F _A or a deformation .DELTA.x be replaced.

The simulation device 1 also has an interface 12 on which parameters for the machine simulation MS can be entered. the interface 12 is ideally the input mask 11 at the control unit 3 the injection molding machine 2 ,

The control or control unit 3 the injection molding machine 2 is via a data connection 12 with the simulation device 1 connected. About this data connection 12 For example, it is possible to have an adjustment data set determined by simulation directly to the control or control unit 3 the injection molding machine 2 pass. The design of the data connection 12 is unimportant. By modern communication networks, for example, arbitrarily large spatial separations of injection molding machine 2 and simulation device 1 will be realized.

In 2 FIG. 2 shows a flowchart of a simulation method according to the invention, with the steps carried out by the machine simulation MS being shown on the left-hand side and those carried out by the process simulation PS on the right-hand side. By default, the injection of the plastic material is followed by a rate-controlled phase followed by a pressure-controlled phase. In the flowchart shown the required switching by a decision maker E is taken into account.

In detail, in the first simulation step (t _E = 0), a volume flow V. calculated and passed this and the process simulation. This then calculates the pressure in the melt and passes it back to the machine simulation MS. After a counter for the simulation steps has been increased, a decision E decides whether to switch from the speed-controlled to the pressure-controlled phase. If not, in the next simulation step, a new volume flow V is again generated by the machine simulation MS. calculated.

If it is switched, in the first simulation step of the pressure-controlled phase (t _N = 0), a volume flow V is again. calculated and transferred to the process simulation PS. Again, a pressure p in the melt is calculated and passed on to the machine simulation MS. After the new pressure-controlled phase counter has also been increased, a decision is made as to whether the end of the pressure-controlled phase has been reached. This is done in this embodiment simply over a predetermined number of time steps t _N-soll , if this is to be answered with no, in the next simulation step of the pressure-controlled phase again a volume flow V. calculated.

Although it is customary for process simulations PS of the prior art to be delivered in the pressure-controlled phase predetermined pressures. If, however, the setpoint pressures from the machine simulation MS were simply forwarded to the process simulation PS, the machine behavior would be disregarded. To fully exploit the advantages of the invention, in this embodiment as well as in the pressure-controlled phase, a volume flow V. passed on to the process simulation PS.

When the end of the pressure-controlled phase is reached, the simulation stops.

Claims (25)

Method for simulating an injection molding process using an injection molding machine ( 2 ) with an input mask ( 11 ) for data entry, wherein - in a machine simulation (MS) for simulating the injection molding machine ( 2 ) optionally without injection mold due to a physical behavioral model at least one first parameter - preferably a volume flow (V.) - In an injection unit to be simulated ( 9 ) an injection molding machine ( 2 ) is calculated and - in a process simulation (PS) for simulating an injection molding material to be processed and / or an injection mold on the basis of a physical model at least a second parameter - preferably a pressure (p) - is calculated in the injection molding material to be simulated, characterized in that the at least one second parameter of the machine simulation (MS) is communicated and / or the at least one first parameter of the process simulation (PS) is communicated and that an interface ( 12 ) is used to enter parameters for the machine simulation (MS), which the input mask ( 11 ) of the injection molding machine ( 2 ) corresponds. A method according to claim 1, characterized in that in the machine simulation (MS) and / or in the process simulation (PS) at least one temperature (T) of an injection mold to be simulated ( 10 ) is calculated and the at least one temperature (T) of the process simulation (PS) and / or the machine simulation (MS) is communicated. A method according to claim 1 or 2, characterized in that the behavior of a tool heating controller is simulated by the machine simulation (MS). Method according to at least one of claims 1 or 2, characterized in that in the machine simulation (MS) at least one position (x) and / or at least one speed (v) of a movable platen to be simulated ( 6 ) and that the at least one position (x) and / or the at least one speed (v) is communicated to the process simulation (PS). Method according to at least one of claims 1 to 4, characterized in that in the machine simulation (MS) at least one force (F) is applied to a mold mounting plate ( 6 ) and that the at least one force (F) is communicated to the process simulation (PS). Method according to at least one of claims 1 to 5, characterized in that in the process simulation (PS) at least one Auftreibkraft (F _A ), which is affected by the injection molding material to be simulated, is calculated and that the at least one Auftreibkraft (F _A ) of the Machine simulation (MS) is communicated. Method according to at least one of claims 1 to 6, characterized in that in the process simulation (PS) the flow behavior of the injection molding material is reproduced in a machine nozzle and preferably in a screw antechamber. Method according to at least one of claims 1 to 7, characterized in that in the process simulation (PS) or the machine simulation (MS) of the Plasitifiziervorgang - a plasticizing and / or a temperature distribution and / or a pressure distribution of the molten injection molding material - is modeled. Method according to at least one of claims 1 to 8, characterized in that in the machine simulation (MS) and / or in the process simulation (PS) at least one deformation (Δx) of a part - in particular of an injection molding tool ( 10 ) - an injection molding machine to be simulated ( 2 ) and that the deformation (Δx) is communicated to the process simulation (PS) and / or the machine simulation (MS). A method according to any one of claims 1 to 9, characterized in that in the simulation equipment (MS) components of the injection molding machine and / or in the process simulation (PS) components of the injection mold are replicated interchangeable. Method for creating an adjustment dataset for an injection molding machine ( 2 ), characterized in that at least one simulation is carried out according to a method according to at least one of claims 1 to 10, and the set-up data record is created on the basis of a simulation result. Method for simulating a test plan, characterized in that methods according to at least one of claims 1 to 11 are performed repeatedly with varying initial parameters. Simulation device for simulating an injection molding process using an injection molding machine ( 2 ) with an input mask ( 11 ) for data entry, wherein - in a machine simulation (MS) for simulating the injection molding machine ( 2 ) optionally without injection mold due to a physical behavioral model at least one first parameter - preferably a volume flow (V.) - In an injection unit to be simulated ( 9 ) an injection molding machine ( 2 ) is calculable and - in a process simulation (PS) for simulating a material to be processed and / or an injection mold on the basis of a physical model at least a second parameter - preferably a pressure (p) in an injection molding material to be simulated - is calculated, the simulation device ( 1 ) an interface ( 12 ) for inputting parameters for the machine simulation (MS), characterized in that the at least one second parameter is retrievable by the machine simulation (MS) and / or the at least one first parameter is retrievable by the process simulation (PS) and the input mask ( 11 ) of the injection molding machine ( 2 ) of the interface ( 12 ) corresponds to the machine simulation (MS). Simulation device according to claim 13, characterized in that in the machine simulation (MS) and / or in the process simulation (PS) at least one temperature (T) of an injection mold to be simulated ( 10 ) is calculable and the at least one temperature (T) of the process simulation (PS) and / or of the machine simulation (MS) is retrievable. Simulation device according to claim 14, characterized in that the behavior of the tool heating controller can be simulated by the machine simulation (MS). Simulation device according to claim 13 or 14, characterized in that in the machine simulation (MS) at least one position (x) and / or at least one speed (v) of a movable platen to be simulated ( 6 ) is calculable and that the at least one position (x) and / or the at least one speed (v) is retrievable by the process simulation (PS). Simulation device according to at least one of claims 13 to 16, characterized in that in the machine simulation (MS) at least one force (F) on a mold mounting plate to be simulated ( 6 ) is calculable and that the at least one force (F) is retrievable by the process simulation (PS). Simulation device according to at least one of claims 13 to 17, characterized in that in the process simulation (PS) at least one Auftreibkraft (F _A ), which is influenced by the simulated injection molding material, is calculable and that the at least one Auftreibkraft (F _A ) of the machine simulation (MS) is retrievable. Simulation device according to at least one of claims 13 to 18, characterized in that in the process simulation (PS) the flow behavior of the injection molding material in a machine nozzle and preferably in a screw antechamber is simulated. Simulation device according to at least one of claims 13 to 19, characterized in that in the process simulation (PS) or the machine simulation (MS) of the plasticizing - a plasticizing and / or a temperature distribution and / or a pressure distribution of the molten injection molding material - is simulated. Simulation device according to at least one of claims 13 to 20, characterized in that in the machine simulation (MS) and / or in the process simulation at least one deformation (Δ _X ) of a part - in particular of an injection molding tool ( 10 ) - an injection molding machine to be simulated ( 2 ) and that the at least one deformation (Δ _X ) can be called up by the process simulation (PS) and / or by the machine simulation (MS). Simulation device according to at least one of claims 13 to 21, characterized in that in the machine simulation (MS) components of the injection molding machine and / or in the process simulation (PS) components of the injection mold are exchangeable simulated. Simulation device according to at least one of claims 13 to 22, characterized in that the simulation of an injection molding process with varying initial parameters is repeatable. Injection molding machine with simulation device according to at least one of claims 13 to 22, characterized in that the simulation device ( 1 ) with a control or regulating device ( 3 ) of the injection molding machine ( 2 ) connected is. Injection molding machine according to claim 24, characterized in that input parameters of the machine simulation (MS) of the control or regulating device ( 3 ) of the injection molding machine ( 2 ) can be taken over as setting data record.

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