METHOD FOR ESTABLISHING A TARGET VALUE

Abstract

A target value progression for a process parameter functioning as a setting variable is established so that an actual value progression for a selected variable has a desired property, or the desired actual value progression itself ensues. The actual value progression occurring in relation to the first configuration is predetermined as a reference value progression for the selected variable, and a target value progression for the process parameter functioning as the setting variable is established by a computer so that the reference value progression as the actual value progression with the desired property or the desired actual value progression itself ensues when the shaping machine in the second configuration operates in a production cycle in accordance with the selected target value progression for the at least one process parameter functioning as the setting variable.

Claims

1. A method of establishing a target value progression for at least one process parameter functioning as a setting variable of a production cycle of a cyclically operating shaping machine, in particular an injection moulding machine, wherein an actual value progression for at least one variable preferably different from the process parameter functioning as a setting variable ensues when the shaping machine operates in a production cycle in accordance with the target value progression for the at least one process parameter functioning as the sertting variable, wherein at least one desired property of the actual value progression is predetermined for the at least one selected variable or a desired actual value progression itself and a target value progression for the at least one process parameter functioning as the setting variable is so established by a computer that—possibly within a predetermable or predetermined tolerance range—an actual value progression for the at least one selected variable with the at least one desired property or the desired actual value progression itself ensues, wherein A. with a shaping machine in a first configuration in at least one production cycle the target value progression for the at least one process parameter functioning as the setting variable is so established that an actual value progression for the at least one selected variable has the desired property or the desired actual value progression itself ensues, B. in a shaping machine in a second configuration different from the first configuration the actual value progression occurring in relation to the first configuration is predetermined as a reference value progression for the at least one selected variable and a targe value progression for the at least one process parameter functioning as the setting variable is so established by the computer that—possibly within a predeterminable or predetermined tolerance range—the reference value progression ensues as the actual value progression with the desired at least one property or the desired actual value configuration itself when the shaping machine in the second configuration operates in a production cycle in accordance with the selected target value progression for the at least one process parameter functioning as the setting variable.

2. The method according to claim 1, wherein the shaping machine in its first configuration and/or in its second configuration is in the form of a simulation simulatable by a computer and the operation of determining the actual value progression is effected using the simulation and a computer by a target value progression for the at least one process parameter functioning as the setting variable being so established by the computer that the actual value progression afforded by the simulation has the at least one selected property or the desired actual value progression itself ensues.

3. The method according to claim 1, wherein the shaping machine in its first configuration and/or in its second configuration is in the form of a physically existing shaping machine and the operation of determining the actual value progression is effected using the physically existing shaping machine by a target value progression for the at least one process parameter functioning as the setting variable being so established by the computer that the actual value progression at the physically existing shaping machine has the at least one selected property or corresponds to the desired actual value progression.

4. The method according to claim 1, wherein the shaping machines in the first and the second configuration use the identical or the same moulding tool in which at least one moulding is produced in the production cycle but are different from each other in relation to at least one of the features listed hereinafter: plasticizing unit of the shaping machine which serves to produce a moulding material for introduction into a moulding tool and/or to introduce it into the moulding tool, preferably a drive unit of the plasticising unit and properties of the screw, particularly preferably the diameter thereof, an injection unit which serves to introduce a moulding material into a moulding tool, a drive unit or electrical or hydraulic drive type, a closing unit, in particular compression moulding processes, material used for the moulding material, differences in regard to the production tolerances, machine parametrisation, preferably controller setting or increased injection pressure.

5. The method according to claim 1, wherein the at least one process parameter of a production cycle, functioning as the setting variable, and the at least one selected variable which ensues when the shaping machine in a production cycle operates in accordance with the target value progression for the at least one process parameter functioning as the setting variable relate to a plasticising process and/or an injection process of the production cycle.

6. The method according to claim 1, wherein the at least one process parameter functioning as the setting variable and/or the at least one selected variable is or are selected from the list hereinafter: a time-dependent or travel-dependent profile of an injection speed of moulding material into a shaping tool, a time-dependent or travel-dependent profile of an injection volume of moulding material into a shaping tool, switchover point from a time-dependent or travel-dependent profile for an injection speed of moulding material into a shaping tool to a time-dependent pressure profile, profile of a holding pressure after filling of a shaping tool with moulding material, time-dependent or travel-dependent profile of a metering speed of a plasticising unit, time-dependent or travel-dependent profile of a dynamic pressure of a plasticising unit, time-dependent or travel-dependent profile of a closing movement of a closing unit, time-dependent or travel-dependent profile of an ejection movement of an ejection device.

7. The method according to claim 5, wherein a portion-wise or complete progression in respect of the at least one selected variable is selected from the list hereinafter: progression of a pressure of the moulding material at at least one selected position of the shaping machine, preferably avoiding peaks going beyond a predeterminable limit value, progression in a volume flow of moulding material into a shaping tool, progression in the speed during the holding pressure phase, flow front speed, mould internal pressure, metering speed of a plasticising unit, dynamic pressure of a plasticising unit, plasticizing moment of a plasticising unit, closing speed and/or closing force and/or torque of a drive unit of a closing unit, ejection speed and/or ejection force and/or torque of a drive unit of an ejection device.

8. The method according to claim 1, wherein the at least one selected property of the actual value progression for the at least one selected variable is selected from the list hereinafter: avoiding or limiting peaks in the actual value progression, limiting the first and/or a higher derivitive of the actual value progression, predetermining reference points on the curve and associated tolerance ranges, minimum and maximum values in given process phases or at specific travel or time points, maximum required time for carrying out a movement or selected phases of the production cycle or the entire production cycle, maximum amount of material which is injected by way of holding pressure, portion-wise or complete appearance of a time-dependent or travel-dependent progression.

9. A method of open-loop or closed-loop control of a cyclically operating shaping machine, in particular an injection moulding machine, wherein a target value progression is predetermined for at least one process parameter of a production cycle of the cyclically operating shaping machine for open-loop or closed-loop control, wherein an actual value progression for at least one variable ensues when in a production cycle the shaping machine operates in accordance with the target value progression for the at least one process parameter and wherein at least one desired property of the actual value progression for the at least one selected variable or a desired actual value progression itself is predetermined, wherein a target value progression established in accordance with the method according to claim 1 is used as the target value progression, in order to display to an operator of the shaping machine how a target value progression is to be selected or a prevailing target value progression is to be altered so that the actual value progression for the at least one selected variable with the at least one selected property or the desired actual value progression itself ensues, or automatically set, open-loop control or closed-loop control the at least one process parameter by a computer.

10. A computer program product including commands which in execution of the program by a computer cause it to carry out the method according to claim 1.

11. A computer program product including commands which in the execution of the program by a computer cause it by carrying out step A of the method according to claim 1 to determine an actual value progression, to encode same in the form of data and to store the encoded data, preferably in the form of a parts data set in relation to a uniquely identifiable moulding tool for a shaping machine in a storage medium.

12. A computer program product including commands which in the execution of the program by a computer cause it using an actual value progression stored in the form of encoded data in a storage medium by carrying out step B of the method according to claim 1 to establish a target value progression for the at least one process parameter functioning as the setting variable.

13. A cyclically operating shaping machine, in particular an injection moulding machine, having a moulding tool, wherein the shaping machine has a computer or can be brought into data-transmitting communication with such, which is configured to carry out the method according to claim 1.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0079] The state of the art and the invention are discussed hereinafter with reference to the Figures in which:

[0080] FIGS. 1 and 2 show the problems in the state of the art,

[0081] FIG. 3 shows a target value progression and a desired actual value progression,

[0082] FIG. 4 shows an unwanted actual value progression occurring for the target value progression of FIG. 3 in a shaping machine involving a different configuration,

[0083] FIG. 5 shows the required adaptation of the target value progression so that the desired actual value progression ensues within a predetermined tolerance range,

[0084] FIG. 6 shows a shaping machine according to the invention in a first configuration,

[0085] FIG. 7 shows a shaping machine according to the invention in a second configuration, and

[0086] FIG. 8 shows a diagrammatic representation of the method according to the invention of ascertaining a target value progression and providing for open-loop or closed-loop control of a shaping machine with that target value progression.

DETAILED DESCRIPTION OF THE INVENTION

[0087] FIG. 1 shows by way of example an initial target value progression 1 which is predetermined by a user or at the factory for a process variable P functioning here as a setting variable u.sub.p “injection speed v” of a cyclically operating shaping machine 2, 2′ in the form of the plastic injection moulding machine in accordance with the state of the art. At predetermined positions x.sub.0, x.sub.1, x.sub.2, x.sub.3 of an injection ram the injection speed v is changed to a given value, wherein at the position x.sub.U (switchover point) switching over from closed-loop speed control to closed-loop pressure control is effected.

[0088] FIG. 2 shows the ensuing actual value progression 3 for a selected variable G in the form of the “injection pressure p”. This actual value progression 3 does not have the desired property E in relation to “avoiding or limiting peaks in the actual value progression” as two pressure peaks can be seen at the times t.sub.1 and t.sub.2. In the state of the art the user now has to change the target value progression 1 for the injection speed v in such a way that the desired actual value progression (symbolised by the illustrated arrows) ensues, which no longer has the pressure peaks.

[0089] FIG. 3 shows by way of example a target value progression 1 for a process parameter P, functioning as a setting variable u.sub.P, of a production cycle of a cyclically operating shaping machine 2, 2′, in particular an injection moulding machine, in a first configuration (for example with a hydraulic drive unit HM for the injection ram of a plasticising unit of the shaping machine 2, 2′ —see the diagrammatic view in FIG. 6), wherein there is an actual value progression 3 for at least one variable G if in a production cycle the shaping machine 2, 2′ operates in accordance with the target value progression 1 for the at least one process parameter P functioning as a setting variable u.sub.P. In this example the target value progression 1 is in the form of six presetting values for the process parameter P (which naturally is not essential to the invention, it would be possible to provide fewer or more presetting values—up to such a high number of presetting values that there is a continuous progression). The variable G which was measured or simulated in a virtual simulation is here in the form of a continuous actual value progression 3 (which naturally is not essential to the invention, fewer presetting values could be provided, like for example a discrete, that is to say sampled, progression).

[0090] The way in which, for the desired actual value progression 3 of the variable G, the associated target value progression for the process parameter P functioning as the setting variable u.sub.P can be ascertained has already been described. What is now essential is that the desired actual value progression 3 is encoded by a computer program product according to the invention in executing the program by a computer 4 in the form of data and the encoded data, preferably in the form of a parts data set in relation to a uniquely identifiable moulding tool 6 for a shaping machine 2, 2′ are stored in a storage medium 7.

[0091] If now the same target value progression were simply selected for the process parameter P as in FIG. 3, for the identical or the same moulding tool 6 mounted in a shaping machine 2′ of a second configuration (for example with an electrical drive unit EM for the injection ram of a plasticising unit of the shaping machine 2′, but otherwise of the same structure with the shaping machine 2 in the first configuration—see the diagrammatic view in FIG. 7), then by way of example that would give the unwanted actual value progression 3 shown in FIG. 4, with a large number of peaks.

[0092] Using a computer program product according to the invention including commands which in the execution of the program by a computer 4 cause it to establish a target value progression 1 for the at least one process parameter P functioning as the setting variable u.sub.P, using an actual value progression 3 stored in the form of encoded data in a storage medium 7, by carrying out step B of the method, then the computer can make the required modification in the target value progression 1, as is diagrammatically shown in FIG. 5. In that respect the arrows show the displacements to the new presetting values which are shown as crosses. In that respect it is not absolutely necessary for the actual value progression 3 which was produced in relation to the shaping machine 2 of the first configuration to be reproduced identically, but it may be sufficient if the actual value progression 3 is within a predetermined or predeterminable tolerance range.

[0093] FIG. 8 shows a diagrammatic view of the method according to the invention of ascertaining a target value progression 1 and providing for open-loop or closed-loop control of a shaping machine 2, 2′ with that target value progression 1. The following are provided: [0094] a module 8 for calculating a deviation of the selected property E of the variable G of the measured actual value progression 3 or the measured actual value progression 3 itself from a desired actual value progression 3, [0095] a module 9 for adaptation of the target value progression 1 for the process parameter P, [0096] a module 10 for presetting a selected property E of the variable G of the actual value progression 3 or the actual value progression 3 itself for the process parameter P, [0097] a module 11 for presetting an initial value for the setting variable u.sub.P, and [0098] a measuring device 12 for measuring the actual value progression 3.

[0099] A selected desired property E of the variable G can be preset by a user by way of the module 10. Alternatively it would also be possible to directly preset a desired actual value progression 3 by way of that module 8.

[0100] Initial values for the setting variable u.sub.P can be preset by a user or at the factory by way of the module 11. At least one production cycle of the shaping machine 2, 2′ is implemented with the values preset by way of the module 11 and the ensuing actual value progression 3 is measured by way of the measuring device 12 and passed to the module 8.

[0101] That module calculates—for example with the discussed algorithm—a deviation in the selected property E of the variable G of the measured actual value progression 3 or the measured actual value progression 3 itself from a desired actual value progression 3 and by way of the module 9 implements adaptation of the target value progression 1 for the process parameter P (for the setting variable u.sub.P), that is to say setting to a new target value progression 1.

[0102] If necessary that process can be iteratively repeated until the deviation of the selected property E of the variable G of the measured actual value progression 3 or the desired actual value progression 3 itself from a desired actual value progression 3 is within a predetermined or predeterminable tolerance range 5. The tolerance range 5—as shown here by way of example—can be symmetrical around the desired actual value progression 3, but that is not absolutely necessary, an asymmetric configuration can possibly also be selected.

LIST OF REFERENCES

[0103] 1 target value progression for a process parameter P functioning as a setting variable [0104] 2, 2′ cyclically operating shaping machine [0105] 3 actual value progression for a variable G [0106] 4 computer [0107] 5 tolerance range [0108] 6 moulding tool [0109] 7 storage medium [0110] 8 module for calculating a deviation in the selected property E of the variable G of the measured actual value progression or the measured actual value progression itself from a desired actual value progression [0111] 8 module for adaptation of the target value progression for the process parameter P [0112] 9 module for presetting a selected property E of the variable G target value progression for the process parameter P [0113] 10 module for presetting an initial value for the setting variable u.sub.P [0114] 11 measuring device for measuring the actual value progression [0115] P process parameter [0116] G selected variable [0117] E desired property of the actual value progression for the selected variable [0118] u.sub.P setting variable for the process parameter [0119] v injection speed [0120] x.sub.0,x.sub.1,x.sub.2,x.sub.3 predetermined positions of an injection ram [0121] x.sub.U switchover point [0122] p pressure of the moulding material [0123] t.sub.1,t.sub.2 moments in time