JPH0737060B2 - Injection molding machine controller - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to an injection molding machine control device for controlling an injection molding machine that molds and manufactures plastic products.

(Prior Art) In order to mold a good plastic product of stable quality, the operating conditions of the injection molding machine must be constantly changed based on various conditions. For example, in the case of 24-hour operation, since the nighttime and daytime air temperatures fluctuate greatly, it is necessary to prevent the occurrence of defects by finely adjusting the injection speed, the injection pressure, etc. according to such changes in external conditions. However,
Conventionally, such fine adjustment of operating conditions has been performed by relying on the experience and intuition of the operator, so that it has not been possible to reliably prevent the occurrence of defective products.

Various systems have been proposed as a system of a control device for preventing a quality variation of a plastic product by an injection molding machine. For example, there are a method of finely adjusting the filling stroke by detecting the die closing amount, and a method of finely adjusting the injection pressure by detecting the resin pressure in the die. Any of these methods
The quality fluctuation caused by the fluctuation of the disturbance element is controlled by one predetermined method. That is, the items to be adjusted and the calculation method of the adjustment amount are predetermined. Therefore, if the fluctuation of the disturbance element is predetermined, fine adjustment can be performed by the conventional control method, but if the disturbance element is different, the control by that method may not be effective. It was

The quality of the molded product depends not only on the molding conditions such as injection pressure, injection speed and filling stroke, but also on the shape of the molded product (plate shape, container shape, thick shape, thin shape, fine uneven shape, etc.) and raw material. It also depends greatly on the type. Even if the quality changes (sink, silver stroke, etc.) are the same,
It is usual that the adjustment means to be taken to eliminate the cause of the occurrence of the problem is different. Therefore, there is a problem that the control by one fixed method may not be effective depending on the shape of the molded product and the properties of the raw material used.

Further, conventionally, there is a control method in which the molding conditions are updated and the molding is performed such that the molding conditions are not sequentially controlled by only one molding condition but the molding conditions are sequentially switched as the mold temperature rises. However, this method also determines the update value and update timing of the molding condition in advance and updates the molding condition according to the molding cycle, so even if there are other disturbance factors or quality fluctuations, these There was a problem that it could not be dealt with.

(Problems to be Solved by the Invention) As described above, in the conventional control method of the injection molding machine, it is not possible to appropriately respond to a variation in which the disturbance element exceeds the expected range, and the quality is It was not possible to mold a stable and good plastic product.

The present invention has been made in consideration of the above circumstances, and has a flexible injection molding machine control that can always be controlled by an appropriate method with respect to fluctuations in disturbance factors, shapes of molded products, properties of raw materials, and the like. The purpose is to provide a device.

[Structure of Invention]

(Means for Solving the Problems) In order to achieve the above object, the injection molding machine control device of the present invention provides a method for controlling the injection molding machine based on the value of a process parameter associated with the molding state of the injection molded machine. A storage unit that stores a plurality of production lot data including a determination unit that determines quality, control information about various lots and / or various production conditions, and a destination table that indicates a destination corresponding to the result of the determination. And a production lot data memory for storing the production lot data of the lot currently produced by the injection molding machine, and the injection molding machine based on the control information of the production lot data stored in the production lot data memory. And a destination table of the production lot data stored in the production lot data memory, and the result of the determination is referred to. A second control unit that determines a destination based on the result, and stores the production lot data of the determined destination among the plurality of production rod data stored in the storage unit in the production lot data memory, Each of the control information contained in the plurality of production lot data stored in the storage unit is based on the above process parameters, and also regarding a certain production condition, regarding a stepwise control from one control state to the other control state. The destination table included in each of the plurality of production lot data stored in the storage unit, which is associated with each control stage, is a storage location of the production lot data including the destination table in the storage unit. , Including control information corresponding to two control stages adjacent to one control stage corresponding to the control information included in the production lot data 2
The storage location of the one production lot data in the storage unit is shown.

(Operation) The production lot data including the destination table corresponding to the judgment result is stored in the plural storage units corresponding to the continuous control steps, and based on the judgment result of the judgment unit for judging the molding quality. The production lot data to be used next is determined by referring to the destination table in the production lot data, and the determined production lot data is stored in the production lot data memory from the storage unit. At this time, the destination table defines the production lot data of the selected control stage and the control stage adjacent thereto. The injection molding machine is controlled by the production lot data stored in the production lot data memory. As a result, smooth and extremely flexible control can be performed without giving a sudden change in the control state.

(Embodiment) FIG. 1 shows an injection molding machine control device according to an embodiment of the present invention. The injection molding machine 10, which is a control target of the injection molding machine 11, molds a thermoplastic resin and a thermosetting resin.The molding material is heated and melted in an injection cylinder, and the fluidized molding material is injected by an injection screw. A plastic product is molded by applying pressure into a closed mold and injecting it. The injection molding machine 10 is provided with a sensor 10A for detecting process parameters representing various states of the injection molding machine 10 and an actuator 10B for moving each part of the injection molding machine 10. As the sensor 10A, for example, as a process parameter, a position sensor that detects the mold opening amount, a pressure sensor that detects the cavity pressure, a timer that measures the filling time, a position sensor that detects the cushion amount, and a resin temperature are detected. Temperature sensor, a temperature sensor for detecting a mold temperature, a sensor for detecting an injection (filling) speed, a pressure sensor for detecting an injection pressure (holding pressure), a sensor for detecting an actual screw torque, and the like.

As the actuator 10B, pressure applying means for applying pressure to the mold, motor for rotating the screw, pressure applying means for applying injection pressure or screw back pressure, mold heating means for heating the mold, resin for heating the resin There are heating means and the like.

A determination unit 12 for determining the molding quality is connected to the sensor 10A of the injection molding machine 10. A set value memory 14 for determining the molding quality is connected to the determination unit 12. The determination unit 12 compares the detection signal of the process parameter from the sensor 10A with the set value stored in the set value memory 14 to determine the molding quality.

For example, when the molding quality is determined in terms of the cushion amount as a certain production condition, the set value memory 14 stores the upper limit cushion amount and the lower limit cushion amount for the standard quality. If the detected cushion amount is between the lower limit cushion amount and the upper limit cushion amount, it is determined that the cushion amount is appropriate and the molding quality is good. If the detected cushion amount is smaller than the lower limit cushion amount, it is judged that the cushion amount is too small and the molding quality is poor. Conversely, if the detected cushion amount is larger than the upper limit cushion amount, the cushion amount is too large and the molding quality is bad. Is judged to be defective.

The determination output of the determination unit 12 is input to the storage unit 16 which is the second control unit. The storage unit 16 stores the storage unit 18 based on this determination output.
One is selected from the production lot data stored in and stored in the production lot data memory 20.

That is, if the judgment output is that the molding quality is good,
Since the production lot data currently stored in the production lot data memory 20 does not need to be changed, the storage unit 16 does not store the production lot data. If the judgment output is that the molding quality is poor, more suitable production lot data is selected from the production lot data stored in the storage unit 18, and the selected production lot data is stored in the production lot data memory 20. To do.

How to select the production lot data to be stored in the storage unit 16 will be described with reference to FIGS. 2 and 3. FIG. 2A shows the structure of production lot data. The production lot data is composed of a lot data number column showing the number of the production lot data, a destination table column showing the number of the production lot data to be selected, and a control information column showing various production control information. . In the destination table, the judgment output code and the destination production lot data number are shown in comparison with each other.

A large number of production lot data are stored in the storage unit 18 in advance as shown in FIG. For example, seven types of production lot data of lot data numbers 02 to 08 are prepared for the cushion amount which is a production condition and stored in the storage unit 18.
For these production lot data, lot data number 02 is set as the overpack side, which is one control state, and lot data
03, 04, ... are sequentially set to the short shot side, and control is performed when lot data number 08 is the other control state, that is, the shortest shot. Third between these production lot data
The case of transferring as shown in the figure will be described. FIG. 3 shows that when it is determined that a given production lot data is overpacked, it is transferred to the production lot data in the direction of the arrow pointing to the lower right, and when it is determined that it is a short shot, it is doubled to the upper right. Indicates that the production lot data is transferred in the direction of the arrow. For example, when controlled by the production lot data of lot data number 05 and overpacked, it transfers to lot data number 06, and when it becomes a short shot, it transfers to lot data number 04.

In order to repeatedly execute the transition to the adjacent control state as shown in FIG. 3, the contents of the production lot data stored in the storage unit 18 are set as shown in FIG. 2 (b). . That is, the destination table of these production lot data stores the determination output code (74, 75, 76) and the destination lot data number (02, 03, ..., 08). The determination unit 12 is
A judgment output code of "74" is output if the cushion amount is standard, "75" if the cushion amount is too small (short shot), and "76" if the cushion amount is too large (overpack). In the present embodiment, as shown in FIG. 2B, for example, the production lot data number 04
Destination lot data numbers 04, 03, 05 are stored for the determination codes 74, 75, 76, respectively, and the destination table for the production lot data number 05 stores the determination code
Destination lot data number 05, 74, 75, 76 respectively
04 and 06 are stored, and in the destination table of the production lot data number 06, the destination lot data numbers 06, 05 and 07 are stored for the determination codes 74, 75 and 76, respectively.

The storage unit 16 knows the lot data number corresponding to the determination output code from the determination unit 12 from the destination table of the production lot data memory 20, reads the production lot data of this lot data number from the storage unit 18, and outputs the production lot data memory. 20
To store. However, when the cushion amount is standard, the production lot data stored in the production lot data memory 20 does not change, so that the storage unit 18 does not actually store the production lot data in the production lot data memory 20.

By doing so, the transition as shown in FIG. 3 can be executed.

The production lot data number for the next lot is also described in the destination table of the production lot data of the current lot. When moving to the next lot, the production lot data is updated based on the destination table in the production lot data.

The control unit 22 which is the first control unit controls the injection molding machine 10, and based on the control information of the production lot data stored in the production lot data memory 20, the actuator 10
Drive B.

The control unit 22 is connected to a data input display unit 24 for setting and inputting and displaying data regarding injection control of the injection molding machine 10. That is, at the time of data setting, data is input by operating the data input / display section 24 and the data is set in the production lot data memory 20. During operation of the injection molding machine 10, data indicating the current control state is displayed.

Although various forms of the data input / display unit 24 can be considered concretely, one specific example of the data input / display unit 24 is shown in FIG. Each part of the data input display part 24 will be briefly described.
The program setting unit 31 sets the injection speed, and the injection speed can be set by programming in five steps. The screw position setting unit 32 sets the screw position, and can switch shot size of injection, suck back amount, and program-controlled speed. The injection pressure setting unit 33 sets the injection pressure, and the injection pressure can be programmed in four steps. The timer 34 is for switching the injection pressure in the pressure holding process. The screw rotation speed setting unit 35 is for setting the rotation speed of the screw. The screw back pressure setting unit 36 sets the screw back pressure during plasticization. The data setting unit 37 is for setting data for items that are not always displayed. Which item of data is specified by the code specified in the code section 37A, and its content is set by the data section 37B. In this specific example, since the code part 37A has two digits, the data of 100 kinds of items can be specified by the codes of 00 to 99.
Among these 100 types of codes, there are, for example, the selection of the operation mode of the injection molding machine, the number of required production shots, the number of production completion notice shots for lot switching, the production lot information such as the data identification symbol for the next lot, and the like.

Next, the operation of this embodiment will be described. First, necessary production lot data is created and stored in the storage unit 18. Various methods are possible for this. For example, the production lot data may be created in advance by an external computer and input to the storage unit 18 by a data input means (not shown).
Further, data is manually input from the data input / display unit 24 and stored in the production lot data memory 20, and the production lot data set in this way is stored in the storage unit 18 from the production lot data memory 20. Good. Further, the production lot data in the storage unit 18 that has already been stored is recalled to the production lot data memory 20, and a part of the data is corrected from the data input / display unit 24, and the corrected data is stored in the storage unit 18. You may

When the necessary production lot data is stored in the storage unit 18, the storage unit 16 first reads the standard production lot data from the storage unit 18, stores it in the production lot data memory 20, and then starts the actual operation. In this embodiment, the production lot data of lot data number 05, which is the standard cushion amount, is stored in the production lot data memory 20.

Next, the actual control operation is executed. During the control operation, various monitoring I to IV for extracting the process parameters as shown in FIG. 5 are periodically performed. The cushion amount is detected as one of the monitoring types I to IV. Therefore, the determination unit 12 periodically makes a cushion amount detection determination, and outputs the determination result output to the storage unit 16. The storage unit 16 determines the destination production lot data based on the destination table in the production lot data memory 20 based on the determination result. That is, if the determination output is the standard cushion amount, the storing operation is not performed, and if the determination output is the overpack, the production lot data of the lot data number 06 is stored from the storage unit 18 into the production lot data memory 20, and the determination output is If it is a short shot, the production lot data of lot data number 04 is stored in the storage unit 18 to the production lot data memory 20.
To store.

Since the control of the injection molding machine 10 is made by the production lot data stored in the production lot data memory 20, the transfer of the production lot data as shown in FIG. 3 is performed.

As described above, according to this embodiment, the molding quality is constantly detected, and the production lot data to be used for control is changed based on the data in the production lot data according to the detection result. It can be controlled by various production lot data. Moreover, since these production lot data can be easily modified, extremely flexible control is possible.

The present invention is not limited to the above embodiment, and various modifications can be made.
For example, although the cushion amount is exemplified as the determination item by the determination unit 12 in the above embodiment, other determination items may be used as long as they are related to the molding quality. That is, in addition to the cushion amount, quality judgment items such as filling pressure, mold pressure, screw back pressure, temperature-related judgment items such as mold temperature, nozzle temperature, barrel temperature, hydraulic oil temperature, room temperature, and lot-to-lot variation. Various determination items such as a determination item due to a disturbance such as resin viscosity may be used. By storing the set value for each judgment item in the set value memory 14 and storing the production lot data for updating for each judgment item in the storage unit 18, the production lot data always suitable for various judgment items. The injection molding machine 10 can be controlled by.

Further, the production lot data for some of the above judgment items may be used at the same time. Further, it is possible to perform control with high flexibility.

Furthermore, in the above-described embodiment, the upper limit set value and the lower limit set value are compared as the determination in the determination unit, but not limited to such determination method, various determination methods according to the determination item are possible. Further, a part of the set value used for the determination may be incorporated into the production lot data to change the set value itself.

Thus, according to the present invention, the contents of the data to be changed can be freely set for the judgment items such as the quality variation of the production lot data of each mold, preventing the deterioration of quality and eliminating defects. Also, it is possible to perform fine grained control that meets the detailed requirements of production such as optimization of molding cycle. Specifically, the elimination of defects caused by the shape characteristics of the injection molded product can be dealt with by a different control method for each molded product. For example, optimal control is possible for thick-walled molded products, thin-walled molded products, deep-molded products, flat-plate molded products, lattice-molded products, and the like.

Optimum adjustment of molding conditions suitable for the characteristics of the resin used is possible. That is, the optimum control item can be selected from the barrel temperature, the nozzle temperature, the mold temperature, the filling temperature, the screw back pressure, etc. according to the type of resin.

It is possible to use a control method that makes optimal adjustments for each mold condition against fluctuations that are likely to occur due to features of the mold structure such as direct gates, pin gates, and hot runners.

〔The invention's effect〕

As described above, in the injection molding machine control device of the present invention, since the destination table of each production lot data specifies the adjacent control step, the control data (control information) is replaced with the change of the process parameter. In this case, control is always transferred through each control step in order without skipping the middle of a series of control steps to the control step corresponding to the process parameter detected from the current control step. The setting does not cause disturbance to the injection molding machine, and the control smoothly shifts from the current control to the target control stage. This is a preferable characteristic from the viewpoint of quality control when the control of the injection molding machine is made to follow the environmental conditions such as the ambient temperature that changes gently.

[Brief description of drawings]

FIG. 1 is a block diagram showing an injection molding machine controller according to an embodiment of the present invention, FIG. 2 is a diagram showing a specific example of production lot data in the injection molding machine controller, and FIG. 3 is the same injection molding machine. FIG. 4 is a diagram showing a changed state of production lot data in the control device, FIG. 4 is a diagram showing details of a data input display section in the injection molding machine control device, and FIG. 5 is a flowchart showing a monitoring operation of the injection molding machine control device. Is. 10 ... Injection molding machine, 10A ... Sensor, 10B ... Actuator,
11 ... Injection molding machine control device, 12 ... Judgment part, 14 ... Set value memory, 16 ... Storage part (second control part), 18 ... Storage part, 20 ... Production lot data memory, 22 ... Control part (first Control unit),
24 ... Data input display section.

Claims (2)

[Claims] 1. A determination unit for determining the quality of a molded product based on the value of a process parameter related to the molding state of the molded product in an injection molding machine, and control information on various lots and / or various production conditions. And a storage unit that stores a plurality of production lot data including a destination table indicating a destination corresponding to the result of the determination, and the production lot data for a lot currently produced by the injection molding machine. A production lot data memory, a first control unit for controlling the injection molding machine based on control information of the production lot data stored in the production lot data memory, and a production lot stored in the production lot data memory Among the plurality of production lot data stored in the storage unit, the destination is determined based on the result of the determination by referring to the data destination table. A second control unit for storing the production lot data of the determined destination in the production lot data memory, and each of the control information included in the plurality of production lot data stored in the storage unit. A plurality of values stored in the storage unit, each of which is associated with each control step for stepwise control from one control state to the other control state of a certain production condition based on the process parameter. Destination table included in each of the production lot data of, the storage location in the storage unit of the production lot data including this destination table,
And a storage location in the storage unit of two production lot data including control information corresponding to two control stages adjacent to one control stage corresponding to the control information included in the production lot data. Characteristic injection molding machine control device. 2. The determining means, when the value of the process parameter deviates from an upper limit value or a lower limit value of a predetermined allowable range, whichever of the two adjacent control steps corresponds to the deviating direction. The injection molding machine control device according to claim 1, wherein a determination is made as to whether or not to select.