JPH0737061B2 - Injection molding machine controller - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an injection molding machine control device that controls 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 marks, silver strokes, 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 factor exceeds the expected range, and the quality is stable. No good plastic product could be molded.

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.

(Means for Solving the Problems) In order to achieve the above object, the injection molding machine control device of the present invention determines the quality of the molded product based on the value of the process parameter related to the molding state of the molded product in the injection molding machine. Storage for storing a plurality of production lot data including a determination means (12) for determination, control information on various lots and / or various production conditions, and a destination table indicating a destination corresponding to the result of the determination. Section (18), a production lot data memory (20) for storing the production lot data of the lot currently produced by the injection molding machine, and control information of the production lot data stored in the production lot data memory Refer to the first control section (22) for controlling the injection molding machine based on the above, and the destination table of the production lot data stored in the production lot data memory. A second control unit that determines a destination based on the result of the determination and stores the production lot data of the determined destination among the plurality of production lot data stored in the storage unit in the production lot data memory. (16) in the injection molding machine controller, a unique lot data number is assigned to each of the plurality of production lot data, and the destination table stores the lot corresponding to the plurality of results of the determination. The data numbers are allocated as destination numbers, and the destination numbers of the two production lot data whose lot data numbers are similar to each other are determined so that the assigned destination numbers are shifted by a predetermined number (FIG. 4). It is characterized by

(Operation) The production lot data including the destination table corresponding to the determination result is individually assigned a lot data number and stored in a plurality of sets of storage units. The determination means makes a determination based on a predetermined determination condition, and based on the determination result, 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 determined. The production lot data currently in use is stored in the production lot data memory from the storage section. At this time, in the destination table, lot data numbers are allocated as destination numbers (preferably in order) corresponding to a plurality of determination results, and lot data numbers are similar to each other.
It is defined that the destination numbers assigned to each destination table of one production lot data are shifted (preferably in order) by a predetermined number. Then, the injection molding machine is controlled by the production lot data stored in the production lot data memory.

As a result, an approximate control within a certain range is selected from the current control state according to the determination result, and if the difference between the current control state and the target control state is relatively large, the current control state is selected. Since it is possible to realize a control mode that jumps over the control state on the way to the target control state, it is possible to realize control that is as smooth and responsive as possible. In addition, extremely flexible control is possible.

(Embodiment) An injection molding machine controller according to an embodiment of the present invention is shown in FIG. The injection molding machine 10, which is a control target of the injection molding machine control device 11, molds thermoplastic resin and thermosetting resin.The molding material is heated and melted in the injection cylinder, and the fluidized molding material is injected. A plastic product is molded by injecting pressure into a mold closed by a screw. The injection molding machine 10 includes a sensor 10 for detecting process parameters representing various states of the injection molding machine 10.
A and an actuator 10B for moving each part of the injection molding machine 10 are provided. 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 pressure inside the cavity, a timer that measures the filling time, a position sensor that detects the cushion amount, a temperature sensor that detects the resin temperature, and a mold temperature. Temperature sensor, which detects the injection (filling) speed sensor,
There are a pressure sensor that detects the injection pressure (holding pressure), a sensor that detects the 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 each detection signal of the process parameter from the sensor 10A with the allowable range of the detection signal stored in the set value memory 14, and outputs a predetermined determination result according to a predetermined determination condition for these comparison results. That is, the determination unit 12 uses the second
As shown in the figure, the comparison items 121, 122, ...
12n and a judgment circuit 13 as a comprehensive judgment means for judging by a predetermined judgment condition for these comparison results. , 12n are input with the detection signal from the sensor 10A and the upper limit value and the lower limit value of the allowable range from the set value memory 14, respectively. Each comparison unit 12
1, 122, ..., 12n compare the detection signal with the upper limit value and the lower limit value, and the input detection signal is greater than the upper limit value, between the upper limit value and the lower limit value (within range), or less than the lower limit value. Is output as a comparison result. For example, when the molding quality is determined from the aspect of cushion amount as a certain production condition, in addition to the determination item regarding the cushion amount, the determination items related to the cushion amount include resin temperature, mold temperature, injection temperature, injection If the pressure and the actual screw torque are adopted, a comparison section is provided for each of the plurality of determination items.

The set value memory 14 stores the upper limit value and the lower limit value of the allowable range for each judgment item. Each comparison unit 121 to 12n of the determination unit 12
Outputs a comparison result to the effect that each detected signal detected is between these lower and upper limits, and outputs a comparison result to that effect if each detected signal is smaller than the lower limit, and vice versa. When the detection signal is larger than the upper limit value, the comparison result to that effect is output. In the case of the cushion amount, the comparison results regarding the resin temperature, the mold temperature, the injection temperature, the injection pressure, and the actual screw torque are output from the comparison units 121 to 12n.

The determination circuit 13 outputs a determination result based on a predetermined determination condition for the comparison result of the first stage from each of the comparison units 121 to 12n.
The determination circuit 13 in this embodiment is characterized in that it makes a comprehensive determination based on a plurality of determination conditions.

For example, whether all judgment items are out of the allowable range,
Only one judgment item is out of the allowable range or 2
The production lot data to be updated may be changed based on a plurality of determination conditions such as whether one or more determination items are out of the allowable range. Further, since the production lot data to be updated differs depending on the type of raw material used, the features of the shape of the molded product, and the features of the mold structure, the production lot data corresponding thereto may be stored in the storage unit 18. .

A specific example of the determination operation of the determination circuit 13 is shown in FIG. FIG. 3 is a flowchart when it is determined that the cushion amount, which is a production condition, is an overpack. In this case, three determination items (resin temperature, mold temperature, actual filling stroke) are selected as the determination items, and the determination condition (1) is used as a determination condition as to whether the resin temperature deviates from the allowable range. 2) is a condition for determining whether or not the mold temperature is out of the allowable range, and determination condition (3) is a condition for determining whether or not the actual filling stroke is out of the allowable range. First, step 40
It is determined whether or not the comparison result satisfies the determination condition (1) (whether or not the resin temperature has deviated from the allowable range). If not satisfied, the process proceeds to step 41, and if satisfied, step 48.
Move on to. Next, in step 41, the comparison result is the judgment condition (2).
It is determined whether or not (whether or not the mold temperature has deviated from the allowable range) is satisfied. If not satisfied, the process proceeds to step 42, and if satisfied, the process proceeds to step 45. Next, in step 42, it is judged whether or not the comparison result satisfies the judgment condition (3) (whether or not the actual filling stroke deviates from the permissible range). “74” is output, and if satisfied, the code “75” which is the determination result is output in step 44. In step 45, it is determined whether or not the comparison result satisfies the determination condition (3). If not, the code "76" which is the determination result is output in step 46, and if it is satisfied, the determination result is determined in step 47. The code "75" is output. Then step
At 48, it is determined whether or not the comparison result satisfies the determination condition (2). If not satisfied, the process proceeds to step 49, and if satisfied, the process proceeds to step 52. Next, in step 49, it is judged whether or not the comparison result satisfies the judgment condition (3). If not, in step 50 the judgment result is code “77”.
Is output, and if satisfied, the code “75” which is the determination result is output in step 51. In step 52, it is judged whether or not the comparison result satisfies the judgment condition (3). If not, in step 53 the judgment result is code “76”.
Is output, and if satisfied, the code “75” which is the determination result is output in step 54. By making a determination according to such a flow chart, a determination code according to whether or not the three determination items (resin temperature, mold temperature, actual filling stroke) satisfy the allowable range is output.
That is, a comprehensive determination is made based on a plurality of process parameters. A similar determination flowchart is prepared for the determination operation in the case of a short shot.

The determination code which is the determination result of the determination unit 12 is input to the storage unit 16. The storage unit 16 which is the second control unit selects one from the production lot data stored in the storage unit 18 based on this determination code and stores it in the production lot data memory 20.
That is, the production lot data based on the judgment code is stored in the storage unit.
The production lot data stored in 18 is selected, and the selected production lot data is stored in the production lot data memory 20.

How to select the production lot data to be stored in the storage unit 16 will be described with reference to FIG. Figure 4 (a)
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 (destination number) of the production lot data to be selected, and a control information column showing various production control information. It is configured. The destination table shows the judgment code and the destination production lot data number in comparison.

As shown in FIG. 4B, a large number of production lot data, ..., 03, 04, 05 ,. These production lot data are the production lot data most suitable for various lots and various production conditions. For example, the production lot data numbers are assigned in order according to the degree of control (state) in order to make it easier to understand the correspondence of the stepwise control corresponding to the degree of overpack state or short shot state. It is good to assign.

Therefore, the contents of the production lot data stored in the storage unit 18 are set as shown in FIG. 4 (b). That is, in the destination table of these production lot data, the judgment output code (74, 7
5, 76, 77) and destination lot data number (02, 03, ..., 0)
8) is stored. In the present embodiment, as shown in FIG. 4B, for example, in the destination table of the production lot data number 03, m (in this case, m is 4) determination codes 74,
For each of 75, 76 and 77, m (4 in this case) destination lot data numbers 02, 03, 04 and 05 are stored. The judgment code is displayed in the destination table of production lot data number 04.
Destination lot data number for 74, 75, 76, 77 respectively
03, 04, 05, 06 are stored. Production lot data number 05
In the destination table, destination lot data numbers 06, 05, 06 and 07 are stored for the determination codes 74, 75, 76 and 77, respectively. These destination tables include their own production lot data numbers as an intermediate value, preferably a substantially central value, of the production lot data numbers in order assigned to the plurality of determination output codes. Further, between the destination tables of the production lot data whose data numbers are adjacent to each other, the destination lot data number groups in order associated with the determination code are shifted by a predetermined number n (1 in the embodiment). This allows
Only the control stage within a limited range (destination numbers 02 to 05) from the current control stage (for example, production lot data 03) on the production lot data number sequence is selected, and
Next, the selectable range (for example, the destination numbers 03 to 06 in the production lot data 04 and the destination numbers 04 to 07 in the production lot data 05) is gradually shifted on the same production lot data number sequence. As a result, by assigning a plurality of (preferably sequential) production lot data having similar control information to the destination number of the table, when the difference between the current process state and the target state is relatively large, As will be described later, it is possible to realize control in which the control is repeatedly reached from the current control stage to the control stage corresponding to the detected process parameter by repeatedly shifting the control to an approximate control stage within a certain range. Therefore, it becomes possible to converge to the target state as quickly as possible while preventing the setting of the next control information from causing disturbance to the injection molding machine as much as possible. This is preferable as control for coping with a case where the lot (type) of the mold is changed or a case where the ambient temperature of the apparatus suddenly changes.

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, if the production lot data currently stored in the production lot data memory 20 does not change, the storage unit 18 does not store the production lot data in the production lot data memory 20.

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 section 24 can be considered concretely, FIG. 5 shows a specific example of the data input / display section 24. 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 out a predetermined 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 03 is stored in the production lot data memory 20.
Shall be stored in.

Next, the actual control operation is executed, and during the control operation, various monitoring I to IV for extracting the process parameters as shown in FIG. 6 are periodically performed. The cushion amount is determined as one of the monitoring types I to IV. Therefore, the determination unit 12 periodically determines whether or not the predetermined detection signal is within the allowable range, and outputs the determination output code to the storage unit 16. The storage unit 16 determines the destination production lot data from the determination code based on the destination table in the production lot data memory 20, reads it from the storage unit 18, and stores it in the production lot data memory 20. That is, when the data number of the lot currently being produced is 03, 02 to assigned to the determination output codes 74 to 77 according to the three determination conditions shown in FIG.
Control to change the production lot data up to 05. If the judgment output code 75 is output, the data number of the destination table is 03, so molding is continued under substantially the same molding conditions. If the judgment output code 76 is output, the data is changed to data number 04 in the next molding shot and molding is performed. If the judgment output 76 is continuously output after changing to the production lot data 04, the destination table of the production lot data 04
Since the data number 05 is designated in 76, the data is changed to the production lot data 05. If the judgment output code 74
If is output, control is performed to return to data number 03. In addition, the data number of the lot currently being produced is 03
When, for example, the current state is far from the target state, the determination output code 77 is output and the production lot data is changed to 05. Next production lot data 05
When the judgment output code 77 is output also in the control by, the production lot data is changed to 07. in this way,
If the current state is relatively far from the target state, as described above, a control mode is realized in which the production lot data is randomly selected within a certain range to shift to the target state. The injection molding machine 10 is controlled by the updated production lot data stored in the production lot data memory 20.

As described above, according to the present embodiment, the production lot data to be used for the next control is changed based on various determination conditions for a plurality of determination items, so that the control can be performed with the optimal production lot data. Is. 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, as the determination item by the determination unit 12, the filling pressure,
Quality judgment items such as mold pressure and screw back pressure, temperature related judgment items such as mold temperature, nozzle temperature, barrel temperature, hydraulic oil temperature, room temperature, etc., judgment items due to disturbance such as resin viscosity related to lot-to-lot variation, etc. Various determination items may be used.

Further, although the upper limit set value and the lower limit set value are compared as the determination in the determination unit in the above embodiment, various determination methods according to the determination item are not limited to such determination method. 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 embodiment of the present invention, for the production lot data of each mold, with respect to the determination items such as quality variation, the content of the data to be changed can be freely set, and the deterioration of quality can be prevented, It is possible to fine-tune the control to meet the small demands of production such as eliminating defects and optimizing the 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, thick-walled molded products, thin-walled molded products,
Optimal control is possible for deep-formed products, lattice-formed 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 provide a control method for performing optimal adjustments for each mold condition with respect to variations that are likely to occur due to the 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, a plurality of production lot data is allocated to the destination table indicating the destination corresponding to the determination result (determination output code) of the production lot data referenced by the control unit, And, in the destination table of the production lot data whose lot data numbers are similar to each other, the number of the destination production lot data is shifted by a predetermined number with respect to the same determination result, so that it is assigned. Select an approximate control within a certain range from the current control state, and if the difference between the current control state and the target control state is relatively large, It is possible to realize a control mode that jumps over control steps, and it is possible to realize control that is as smooth and responsive as possible.

[Brief description of drawings]

FIG. 1 is a block diagram showing an injection molding machine control device according to an embodiment of the present invention, FIG. 2 is a block diagram showing details of a determination unit of the injection molding machine control device, and FIG. The flowchart which shows the specific example of the algorithm of the judgment part of the device, FIG. 4 is a figure which shows the specific example of the production lot data in the same injection molding machine control device, and FIG. 5 is the data input display part in the same injection molding machine control device. FIG. 6 is a flow chart showing the monitoring operation of the injection molding machine control device, showing the details. 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 judging means (12) for judging the quality of the 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 various lots and / or various production conditions. Control information, and a storage unit (18) for storing a plurality of production lot data including a destination table indicating a destination corresponding to the result of the determination, the injection molding machine for the lot currently produced A production lot data memory (20) for storing production lot data, a first controller (22) for controlling the injection molding machine based on control information of the production lot data stored in the production lot data memory, The destination table is determined based on the result of the determination by referring to the destination table of the production lot data stored in the production lot data memory, and the destination stored in the storage unit is determined. A second control unit (16) for storing in the production lot data memory the production lot data of the predetermined destination among the production lot data of A unique lot data number is assigned to each of the data, and in the destination table, the lot data numbers corresponding to the plurality of results of the determination are allocated as destination numbers, and two lot data numbers that are close to each other are assigned. An injection molding machine control device, characterized in that the destination numbers assigned to each destination table of the production lot data are set to be shifted by a predetermined number. 2. The injection molding machine control device according to claim 1, wherein the lot data numbers are sequentially allocated as destination numbers in the destination table in correspondence with a plurality of results of the determination. The injection molding machine control device is characterized in that the destination numbers of the two production lot data whose lot data numbers are close to each other are sequentially allocated to each other and are shifted by a predetermined number. .