JPH0729352B2 - Injection molding machine control system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Structure of the Invention (Field of Industrial Application) The present invention relates to an injection molding machine control system for controlling an injection molding machine for molding a plastic product.

(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 output, injection speed and filling stroke, but also on the shape of the molded product (plate, container, 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. For this reason, there is a problem that the control by the conventional method may not be effective depending on the shape of the molded product and the property 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 possible to appropriately respond to the quality fluctuation depending on the disturbance element, the shape of the molded product, and the property of the raw material used. Therefore, it was not possible to mold a good plastic product with stable quality.

The present invention has been made in consideration of the above circumstances, and has a flexibility of an injection molding machine that can always control by appropriate control information with respect to disturbance factors, changes in the shape of molded products, properties of raw materials, and the like. The purpose is to provide a control system.

[Structure of Invention]

(Means for Solving Problems) In the injection molding machine control system having a plurality of injection molding machine control devices installed corresponding to each of the plurality of injection molding machines, In an injection molding machine control system having a plurality of injection molding machine control devices installed corresponding to each other, a value of a process parameter related to a molding state of a molded product in each of the plurality of injection molding machines is transmitted via a bus line. Each of the injection molding machines receives an input from each injection molding machine control device and judges the quality of each molded product, and based on the judgment result of the judgment section, unless the judgment result is good. An update lot data editing unit for editing control information of various lots and / or various production conditions included in the control device, and each injection molding machine control device is provided with the update lot data editing unit. An updated lot data memory that stores the sent control information as control information that should be used during the next shot molding, and a production lot that stores production lot data that includes control information about the lot currently being molded by the injection molding machine. A first memory for controlling the injection molding machine based on a data memory and control information of the production lot data stored in the production lot data memory.
And a second control unit for extracting control information from the updated lot data memory, storing the control information in the production lot data memory at the time of the next shot molding, and replacing the control information up to that time. Is achieved by an injection molding machine control system characterized by.

(Operation) The determination unit and the updated lot data editing unit are shared by the plurality of injection molding machines and the injection molding machine control device. That is, the determination unit determines the quality of the molded product made by each injection molding machine, and the updated lot editing unit edits the content of the control information used in the next shot molding based on the determination result.

On the other hand, each injection molding machine control device is provided with an updated lot data memory, in which control information used during the next shot molding is stored. However, the control information stored in the updated lot data memory is updated to the content edited by the updated lot data memory editing unit.

Then, the second control unit takes out the control information updated in this way from the updated lot data memory, stores it in the production lot data memory at the time of the next shot molding, and stores the difference from the control information used until then. Change.

Since the first control unit controls the injection molding machine using the data in the production lot data memory thus replaced, a molded product of superior quality is obtained in the injection molding of the next shot. be able to.

Here, the updated lot data editing unit also determines the contents of the control information for the next shot molding. Therefore, the update lot data memory does not need to store a plurality of control information in advance, and only the control information sent from the update lot data memory editing unit needs to be stored, so that the memory capacity is small. Will be enough.

(Embodiment) An injection molding machine control system according to an embodiment of the present invention is first described.
Shown in the figure. The injection molding machines 11, 12, ..., 1n to be controlled mold thermoplastic resin and thermosetting resin. The molding material is heated and melted in the injection cylinder, and the fluidized molding material is injected into the injection screw. A plastic product is molded by injecting pressure into a mold closed by. The injection molding machines 11, 12, ..., 1n include the injection molding machines 11, 1
Sensors 11A and 12 for detecting various states of 2, ..., 1n
, 1nA and actuators 11B, 12B, ..., 1nB for moving respective parts of the injection molding machines 11, 12, ..., 1n. As the sensors 11A, 12A, ..., 1nA, for example,
Position sensor for detecting mold opening amount, pressure sensor for detecting cavity pressure, timer for measuring filling time, position sensor for detecting cushion amount, temperature sensor for detecting resin temperature, temperature sensor for detecting mold temperature There is. The actuators 11B, 12B, ..., 1nB include pressure applying means for applying pressure to the mold, a motor for rotating the screw,
Pressure applying means for applying injection pressure and screw back pressure,
There are a die heating means for heating a die, a resin heating means for heating a resin, and the like.

.., 1n common to a plurality of injection molding machines 11, 12, ...
Is provided. The determination unit 112 is the injection molding machine 11, 1
A device for determining the molding quality from the detection signals from the 2 ..., 1n sensors 11A, 12A ,. This determination unit 11
A set value memory 114 for storing set values is connected to 2. Injection molding machines 11, 12, ..., 1n sensors 11A, 12A, ..
1 nA is connected to the determination unit 112 via the bus line 100. The determination unit 112 determines the molding quality by comparing the detection signals from the sensors 11A, 12A, ..., 1nA with the set values stored in the set value memory 114. For example, when determining the molding quality in terms of the cushion amount, the set value memory 114 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 112 is output to the updated lot data editing unit 116. A control information memory 118 storing control information for various lots and various production conditions is connected to the updated lot data editing unit 116. The updated lot data editing unit 116 edits and calculates the control information in the control information memory 118 based on the determination result to generate updated production lot data to be used next. Therefore, the updated lot data editing unit 116 can select and edit control information suitable for various shaped articles and various resins.

This updated production lot data is sent via the bus line 100.
Update data memories 61, 62 of the injection molding machines 11, 12, ..., 1n,
…, Stored in 6n. After storing, update unit (second control unit)
51, 52, ..., 5n are updated data memory 61, 62 ,.
..., store in 7n and update.

However, when the determination result of the determination unit 112 is good, the updated production lot data is not edited and the fact is notified to the update units 51, 52, ..., 5n. Update section 51, 52,
…, 5n does not update the production lot data.

The control units (first control unit) 41, 42, ..., 4n are injection molding machines 1
, 1n, and drives and controls the actuators 11B, 12B, ..., 1nB based on the production lot data stored in the production lot data memories 71, 72, ..., 7n.

The control units 41, 42, ..., 4n have injection molding machines 11, 12 ,.
, 2n for setting and inputting and displaying data relating to injection control are connected. That is, at the time of data setting, this data input display section
Input data by operating 21, 22, ..., 2n,
Data is set in the production lot data memories 71, 72, ..., 7n. When the injection molding machines 11, 12, ..., 1n are operating, data indicating the current control state is displayed.

The data input / display sections 21, 22, ..., 2n may have various concrete forms, and the data input / display section 21, 22 is shown in FIG.
A specific example of 22, ..., 2n is shown. This data input display section 2
Each part of 1, 22, ..., 2n 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 17A, 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. When necessary control information is stored in the control information memory 118, first, standard production lot data is generated in the update lot data editing unit 116, and the update lot data memories 61, 62, ..., 6 via the bus line 100.
Store in n. , 5n store the standard production lot data stored in the updated lot data memories 61, 62, ..., 6n in the production lot data memories 71, 72, ..., 7n. After that, the actual control operation is started.

During the control operation, various kinds of monitoring I to IV as shown in FIG. 3 are regularly performed. These monitoring I ~
Molding quality is detected as a type IV. Therefore, the determination unit 112 periodically performs the detection determination of the molding quality, and the updated lot data editing unit 116 edits the control information based on the determination result and generates the updated production lot data. The updated production lot data is stored in the updated lot data memories 61, 62, ..., 6n. Storage units 51, 52, ..., 5n
Is the updated lot data memory 61, 62, ..., 6n and the updated production lot data in the production lot data memory 71, 72 ,.
To store. , 1n are controlled by the production lot data stored in the production lot data memories 71, 72, ..., 7n.

As described above, according to this embodiment, while constantly detecting the molding quality, the production lot data is re-edited according to the detection result to generate updated production lot data to be used for the next control. It can be controlled by the optimum production lot data. Therefore, extremely flexible control is possible. Further, since a common determination device is provided for a plurality of injection molding machines, the devices around the injection molding machine can be simplified.

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 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 and storing the update control information for various judgment items, multiple injection molding can be performed with the production lot data that is always appropriate for various judgment items. The machine can be controlled.

Further, in the above embodiment, a plurality of injection molding machines are controlled, but the number of injection molding machines may be one.

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.

〔The invention's effect〕

As described above, according to the present invention, the contents of the data to be changed can be freely set for the determination items such as the quality variation for each production lot data, the prevention of quality deterioration and the elimination of defects. In addition, it is possible to control a plurality of injection molding machines, such as optimizing the molding cycle, to meet the production requirements at each time. That is, according to the present invention, optimal control is possible in the following cases.

The elimination of defects caused by the geometrical characteristics of the injection-molded product can be dealt with by different control methods 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, depending on the type of resin, the barrel temperature,
Optimal control items can be selected from nozzle temperature, mold temperature, filling pressure, screw back pressure, and the like.

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.

Further, in the present invention, the updated lot data editing unit edits the content itself of the control information used at the time of molding the next shot, so that it is more effective than selecting the appropriate one from the plurality of control information. Fine control is possible. The updated lot data memory in each injection molding machine control device does not need to have a large capacity capable of storing a plurality of pieces of control information in advance. Therefore,
There is also an advantage that the memory capacity of the entire system can be saved.

[Brief description of drawings]

FIG. 1 is a block diagram showing an injection molding machine control system according to an embodiment of the present invention, FIG. 2 is a diagram showing details of a data input display section in the injection molding machine control system, and FIG. 3 is the injection molding machine. It is a flow chart which shows monitoring operation of a control system. 11, 12, ..., 1n ... Injection molding machine, 11A, 12A, ..., 1nA ...
… Sensor, 11B, 12B,…, 1nB …… Actuator, 2
1, 22, ..., 2n ... Data input display section, 41, 42, ..., 4n
...... Control unit, 51, 52, ..., 5n ...... Update unit, 61, 62, ...,
6n ... Update lot data memory, 71, 72, ..., 7n ... Production lot data memory, 100 ... Bus line, 112 ... Judgment section, 114 ... Set value memory, 116 ... Update lot data editing section, 118 ... Control information memory.

Claims (1)

[Claims] 1. An injection molding machine control system having a plurality of injection molding machine control devices installed corresponding to each of a plurality of injection molding machines, wherein a molding state of a molded product in each of the plurality of injection molding machines is set. The value of the relevant process parameter is input from each injection molding machine control device via the bus line, and the determination unit that determines the quality of each molded product, based on the determination result of the determination unit, the determination result is Except when it is good, each injection molding machine controller is provided with an updated lot data editing unit that edits control information for various lots and / or various production conditions, and each injection molding machine controller is An updated lot data memory that stores the control information sent from the updated lot data editing unit as control information to be used in the next shot molding, and the injection lot machine that the injection molding machine is currently molding. A production lot data memory that stores production lot data including control information about the production lot, and a first control unit that controls the injection molding machine based on the control information of the production lot data stored in the production lot data memory. , Extracting control information from the updated lot data memory,
An injection molding machine control system, comprising: a second control unit that stores this in the production lot data memory at the time of the next shot molding and replaces it with the control information up to that point.