JPH0777749B2 - Control method and apparatus for injection molding machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention is particularly suitable for automatically operating an injection molding machine.
The present invention relates to a control method and apparatus of an injection molding machine for activating an automatic determination function for determining whether a molded product is good or bad.

[Conventional technology]

Generally, in the inspection process of molded products molded by injection molding machine, especially in the case of inspection process of precision molded products, strict inspection is required, which requires a lot of labor and cost. It becomes a cause of hindering driving.

Therefore, recently, the central controller of the injection molding machine,
It has a built-in automatic discrimination function using a computer, and it is also used to judge the quality of molded products. Specifically, if the molding process by automatic operation of the injection molding machine is in a stable state, molding defects caused by changes in molding conditions over time and molding defects caused by external temperature changes and disturbances such as material conditions It can be known by detecting physical quantities related to the injection molding operation in the cycle, for example, injection filling time, plasticizing time, injection end screw position, and other physical quantities. Therefore, in advance, the monitor range is set by the upper limit value and the lower limit value that are the quality judgment criteria for these physical quantities, and the size of the physical quantity detected for each molding cycle is compared with the monitor range. If it exists inside, the molding cycle operation is normal, and the molded product can be regarded as a good product. On the other hand, if the physical quantity is out of the monitor range, the molding cycle operation is abnormal, and the molded product can be regarded as a defective product.

For example, when the physical quantity is the injection end screw position, the maximum value and the minimum value of the screw position are set as the upper limit value and the lower limit value of the monitor range. Since the injection end screw position is a physical quantity that indirectly indicates the amount of resin injected and filled in the mold cavity, when the injection end screw position is smaller than the minimum value, the resin in the mold cavity is overfilled. Therefore, in this case, there is a high probability that burrs are generated in the molded product, and it can be considered as a defective product. On the other hand, when the injection end screw position is larger than the maximum value, the resin in the mold cavity becomes insufficient. Therefore, in this case, it is highly possible that the molded product is sinked, and it can be regarded as a defective product.

Therefore, if the pass / fail judgment signal obtained from the automatic determination function is sent to peripheral equipment such as the molded product ejector or molded product discharge device, the molded products are automatically sorted into good products and defective products, and when defective products occur. To generate an alarm or stop the operation of the injection molding machine. By such an automatic discrimination function, rationalization based on automatic operation, improvement of labor saving, production efficiency, and economic effect of the entire molding process can be enhanced.

By the way, in order for the automatic discrimination function to function accurately and efficiently, it is necessary to start it after the molding process in the injection molding machine reaches a stable state, and usually a predetermined time has elapsed since the automatic operation of the injection molding machine started. It is started after doing.

Conventionally, the following method has been mainly used as a control method for activating the automatic discrimination function.

The first is the method of using the start switch by the main operation.After starting the automatic operation, the operator visually inspects the molded product to be molded in each molding cycle, and that the molding process has reached a stable state. The self-determination function is activated and the automatic determination function is activated by operating the activation switch.

The second method is to use a counter provided in the central controller. This method presets the number of molding cycles estimated to transition to a stable state, and after starting automatic operation,
The counter counts the actual number of molding cycles. Then, when the count number reaches the set number, the automatic discrimination function is automatically activated.

[Problems to be solved by the invention]

However, the above-mentioned conventional control method has the following problems to be solved.

First, when a start switch is used, it requires an operator's intervention before it is started, which requires man-hours, which is a major cause of hindering unmanned operation, labor saving, and improvement in production efficiency. In addition, it is easy to cause human error and quality deterioration such as forgetting to operate the start switch and variations in start timing.In particular, if you forget to operate it, many uninspected products will be produced. Inspection requires a great deal of labor.

On the other hand, when a counter is used, automatic startup is possible without the need for operator intervention, but since it starts up uniformly, it starts up even in an unstable state, allowing accurate pass / fail judgment. This causes troubles and does not start even though the stable state has already been reached, resulting in an increase in waste of non-defective products. That is, since the molding conditions are greatly influenced by external factors such as temperature fluctuations in the outside and the state of the material to be charged, the time required to reach a stable state varies greatly, but this variation cannot be accommodated.

It is an object of the present invention to provide a control method for an injection molding machine and a control device for implementing the method, which solves the problems existing in the conventional techniques.

[Means for Solving the Problems]

The control method of the injection molding machine according to the present invention, after starting the automatic operation of the injection molding machine M, after reaching a stable state, compares the preset monitor range with the size of the physical quantity related to the detected injection molding operation. When activating the automatic discrimination function to judge the quality of molded products, especially after the start of automatic operation, the size of the physical quantity obtained in each molding cycle is the number of times that the physical quantity continuously exists within the monitor range and the monitor range. The number of times that the monitor continuously deviates, and when the number of times that it continuously exists within the monitor range exceeds the preset first target value, the automatic discrimination function is activated and the number of times the monitor falls outside the range continuously. When exceeds the preset second target value, an abnormality command signal for executing at least one of the operation stop of the injection molding machine and the alarm generation is output. After the start of the automatic operation, if the automatic determination function does not start even when the number of molding cycles reaches the preset third target value, an abnormality command signal similar to the above can be output.

Further, the control device 1 of the injection molding machine according to the invention is equipped with an automatic molding function that compares the preset monitor range with the size of the detected physical quantity related to the injection molding operation to judge the quality of the molded product. In the machine M, the size of the physical quantity obtained for each molding cycle from the start of automatic operation is the first detection unit 2 for detecting the number of times of continuous existence within the monitor range, and the number of times of continuous deviation from the monitor range. The second detection unit 7 for detecting is provided, and the activation unit 3 and the monitor range for activating the automatic determination function when the number of times of continuous existence in the monitor range exceeds the preset first target value. When the number of consecutive deviations exceeds a preset second target value, an abnormal command signal is executed to execute at least one of the operation stop of the injection molding machine and the alarm generation. Characterized in that it comprises a first abnormality command section 8 to.

The first detection unit 2 can be configured to include a non-defective item counter unit 4 that counts each molding cycle in which the size of the physical quantity is within the monitor range and that resets when the molding cycle is outside the monitor range. The second detection unit 7 may be configured to include a defective product cycle unit 9 that counts each molding cycle in which the size of the physical quantity is out of the monitor range and that resets when the molding cycle exists in the monitor range. In addition, the starting unit 3 includes a setting unit 5 that sets a first target value and a first target value and non-defective item counter unit 4.
It can be configured to include a comparison unit 6 that compares detection values output from each other and outputs an abnormality command signal that activates the automatic determination function when the detected values exceed the first target value. The part 8 includes a setting part 10 for setting a second target value,
It can be configured by including a comparison unit 11 that compares the second target value with the detection value output from the defective product cycle unit 9 and outputs an abnormality command signal when the detection value exceeds the second target value. Furthermore, if the automatic discrimination function does not start even after the number of molding cycles reaches the preset third target value after the start of automatic operation, at least one of the operation stop of the injection molding machine or the alarm generation is issued. A second abnormality command section 12 that outputs an abnormality command signal that executes one or both of them can be provided.
The second abnormality command section 12 is a cycle counter section 13 that counts the number of molding cycles, and when the detection value output from the cycle counter section 13 exceeds a third target value by the setting section 14, an abnormality command is issued. It can be configured by including a comparison unit 15 that outputs a signal.

[Action]

According to the control method (or the control device) of the injection molding machine of the present invention, after starting the automatic operation of the injection molding machine, first, the first detection unit 2 displays the comparison result of the size of the physical quantity and the monitor range. Then, the number of times the physical quantity is continuously present in the monitor range is detected. That is, the non-defective item counter unit 4 in the first detection unit 2 counts (1 count) if the physical quantity obtained for each molding cycle is within the monitor range, and resets (0 resets) if it is outside the monitor range. As a result, the non-defective item counter unit 4 continues counting only when the physical quantity continuously exists within the monitor range, and the count value increases. On the other hand, the comparison unit 6 included in the activation unit 3 compares the detected value, which is the count value output from the non-defective item counter unit 4, with the first target value preset in the setting unit 5, and the detected value is the first target value. If the value is exceeded, the comparison unit 6 outputs a start command signal and starts the automatic discrimination function based on this start command signal.

At the same time, the second detection unit 7 detects the number of times the magnitude of the physical quantity continuously deviates from the monitor range. That is, the defective product counter unit 9 in the detection unit 7 counts (1 count) if the physical quantity obtained in each molding cycle is out of the monitor range, and resets (0 resets) if it exists in the monitor range. As a result, the defective product counter unit 9 continues counting only when the physical quantity continuously deviates from the monitor range, and the count value increases. on the other hand,
The comparison unit 11 constituting the first abnormality command unit 8 includes a detection value which is a count value output from the defective product cycle unit 9 and a setting unit.
The second target value set in advance in 10 is compared, and if the detected value exceeds the second target value, the comparison unit 11 outputs an abnormal command signal, and based on this abnormal command signal, the injection molding machine M
Stop the operation and / or issue an alarm.

After the start of automatic operation, the cycle counter unit 13 of the second abnormality command unit 12 counts the number of molding cycles from the start of automatic operation. Then, the comparison unit 15 detects the count value output from the cycle counter unit 13 and the setting unit.
The third target value set by 14 is compared, and when the detected value exceeds the third target value and the automatic determination function does not start, an abnormality command signal is output, and the operation of the injection molding machine M is stopped and / or stopped. Issue an alarm.

〔Example〕

Next, preferred embodiments according to the present invention will be described in detail with reference to the drawings.

First, the configuration of the control device 1 according to the present invention and the function of each unit will be described with reference to FIG.

M indicates an injection molding machine, and a central controller (not shown) incorporated therein has an automatic discrimination function. The automatic determination function is a physical quantity related to the molding operation, for example, injection filling time,
Various sensors that detect the weighing time, plasticization time, injection end screw position, etc., the monitor range setting function unit that sets the upper limit value and the lower limit value of each physical quantity that is the monitor range, and the size of the physical quantity and the monitor range are compared. , Which function by a component such as a determination function unit that performs quality determination, and each function unit is executed by using a built-in computer. The monitor range is used to judge the molding stability in the molding process, and is set in a molding test or trial production stage in which a skilled worker determines molding conditions. The monitor range can be obtained by statistically processing the physical quantity obtained at each molding cycle and the obtained quality judgment data by a computer, or by processing a knowledge database by AI.

Then, the central controller outputs a pass / fail judgment signal S for each molding cycle.

The central controller is provided with a start switch for starting the automatic determination function, and the operator can operate the start switch as a main drive to turn the automatic determination function ON / OFF arbitrarily during automatic operation.

On the other hand, the block system shown in FIG. 1 shows the main part of the control device 1 according to the present invention. Reference numeral 4 is a non-defective counter section that constitutes the first detection section 2. The non-defective item counter unit 4 counts 1 when the non-defective judgment signal S is the non-defective judgment signal Sy, that is, when the physical quantity is within the monitor range. In this case, when there are a plurality of physical quantities, the condition is that all physical quantities exist within the monitor range. Further, the non-defective item counter section 4 is provided with a reset terminal 21, and is reset to 0 when the pass / fail determination signal S is the defect determination signal Sn, that is, when the physical quantity is out of the monitor range. In this case, when there are a plurality of physical quantities, 0 is reset if any one of the physical quantities is out of the monitor range. The count value of the non-defective item counter unit 4 is given to the comparison unit 6 as a detection value. Reference numeral 5 denotes a setting unit that sets a first target value in advance. This first target value is given to the comparison unit 6. The setting unit 5 and the comparison unit 6 constitute the activation unit 3. The comparison unit 6 compares the first target value and the detected value, and outputs a start command signal when the detected value exceeds the first target value. The activation command signal is given to the central controller via the activation output unit 22 to activate the built-in automatic discrimination function.

Further, 9 is a defective product cycle unit that constitutes the second detection unit 7. The defective product counter unit 9 counts one when the quality determination signal S is a defect determination signal Sn, that is, when the physical quantity is out of the monitor range. In this case, when there are multiple physical quantities,
If any one physical quantity is out of the monitor range, 1 is counted. Further, the defective product counter section 9 is provided with a reset terminal 23, and is reset to 0 when the good / bad determination signal S is the good determination signal Sy, that is, when the physical quantity is within the monitor range. In this case, when there are a plurality of physical quantities, the condition is that all physical quantities are within the monitor range. Further, the count value of the defective product counter unit 9 becomes the detected value,
It is given to the comparison unit 11. Reference numeral 10 is a setting unit that sets a second target value in advance. This second target value is given to the comparison unit 11. The setting unit 10 and the comparison unit 11 form a first abnormality command unit 8. The comparison unit 11 compares the second target value with the detected value, and outputs an abnormality command signal when the detected value exceeds the second target value. This abnormality command signal is given to the central controller via the abnormality command output unit 25. As a result, the operation of the injection molding machine is stopped or an alarm is generated.

Furthermore, 13 is a cycle counter section that constitutes the second abnormality command section 12. The cycle counter unit 13 sequentially counts the number of molding cycles from the start of automatic operation. The count value of the cycle counter unit 13 is given to the comparison unit 15 as a detection value. Reference numeral 14 is a setting unit that sets a third target value in advance. This third target value is given to the comparison unit 15.
The setting unit 14 and the comparison unit 15 form the second abnormality command unit 12. The comparison unit 15 compares the third target value with the detected value, and when the detected value exceeds the third target value, outputs an abnormality command signal. This abnormality command signal is given to the abnormality command output unit 25, and stops the operation of the injection molding machine in the same manner as described above,
Or an alarm is generated. Such a second abnormality command section 12
By providing the above, it is possible to prevent wasteful molding because the automatic determination function is not activated forever. The function of the second abnormality command unit 12 can be canceled by the activation command signal output from the comparison unit 6 and the abnormality command signal output from the comparison unit 11.

The setting of the first target value, the second target value, and the third target value described above is set in the molding test or trial production stage in which a skilled worker seeks molding conditions, like the setting of the monitor range. Further, the physical quantity obtained for each molding cycle and the obtained quality determination data can be statistically processed by a computer or can be obtained by processing a knowledge database by AI.

Next, the operation of the control device 1 will be described with reference to FIG. 2 and FIG.

First, a target value is set in each setting unit 5, 10, 14. Third
In the figure, the setting unit 5 (non-defective counter side) is set to "3", the setting unit 10 (defective product counter side) is set to "3", and the setting unit 14 (cycle counter side) is set to "10". Is illustrated.

Then, the automatic operation of the injection molding machine 1 is started, the magnitude of the physical quantity obtained in the first molding cycle is compared with the set monitor range, and the pass / fail judgment signal S is output. At this time, since the starting switch is OFF, the cycle counter unit 13 of the second abnormality command unit 12 counts 1 (step 31-
34). If all the good / bad determination signals S for a plurality of physical quantities are good determination signals Sy, the good product cycle unit 4 in the first detection unit 2 counts 1 and the bad product cycle unit 9 in the second detection unit 7 counts as 0. Reset. On the other hand, if there is at least one defect determination signal Sn among the quality determination signals S for a plurality of physical quantities, the defective product cycle unit 9 counts 1 and the non-defective product counter unit 4 resets to 0 (steps 35 to 35).
39). Such a counting operation is sequentially performed in each molding cycle. When the count value of the non-defective item counter unit 4 reaches “3” first, the automatic discrimination function is activated by the activation command signal output from the comparison unit 6 (step 4
0, 41). On the other hand, if the count value of the defective product counter unit 9 reaches “3” first, the operation of the injection molding machine is stopped or an alarm is generated by the abnormality command signal output from the comparison unit 11 (step 42, 43). If the count value of the non-defective product counter unit 4 or the defective product cycle unit 9 does not reach "3", if the cycle counter unit 13 that counts the number of molding cycles reaches "10" first, at this point An abnormality command signal is output from the comparison unit 15, and the operation of the injection molding machine is stopped or an alarm is generated as described above (step 33).

In the case of FIG. 3, since the good discrimination signal Sy in the sixth to eighth molding cycles continues “3” times, the automatic discrimination function is activated from the ninth molding cycle and the automatic discrimination processing is executed. ing. All the molded products up to the eighth time are treated as defective products.

Although the embodiments have been described in detail above, the present invention is not limited to such embodiments. For example, each counter unit may be provided corresponding to a good determination signal or a defective determination signal, or may be provided corresponding to each physical quantity. Also,
The same operation can be performed by using a timer unit instead of each counter unit. Furthermore, the first abnormality command section and the second abnormality command section can be provided if necessary. The operation can be stopped by setting the target value of each counter unit to "0". In addition, the detailed configuration and method can be arbitrarily changed without departing from the scope of the present invention.

〔The invention's effect〕

As described above, the injection molding machine control method and apparatus according to the present invention, after the automatic operation is started, the size of the physical quantity obtained for each molding cycle is continuously monitored within the monitor range and the number of times that the physical quantity continuously exists within the monitor range. When the number of consecutive occurrences within the monitor range exceeds the preset first target value, the automatic determination function is activated and the number of consecutive departures from the monitor range is detected in advance. When the set second target value is exceeded, an abnormal command signal for executing at least one of the operation stop of the injection molding machine and the alarm generation or both is output. Produce an effect.

Since the automatic discriminating function can be activated at an optimum timing, it is possible to accurately and efficiently make a pass / fail determination, prevent quality deterioration, and prevent waste of molded products.

Since it can be automatically started without the need for human intervention, labor saving, rationalization, efficiency improvement, and elimination of human error can be achieved.

It is possible to promptly detect an abnormality at the time of start-up, take appropriate measures, and prevent wasteful molding.

After the automatic operation is started, if the automatic discrimination function does not start even when the number of molding cycles reaches the preset third target value, the injection molding machine is stopped and / or an alarm is issued, causing instability. Such a situation can be prevented, the cause thereof can be detected early and appropriate countermeasures can be taken, and wasteful molding can be prevented.

[Brief description of drawings]

FIG. 1 is a block system diagram of a control device for an injection molding machine according to the present invention, FIG. 2 is a flowchart showing a control method for an injection molding machine according to the present invention, and FIG. 3 is each part controlled by the control method. A table showing specific examples of the states, in the drawing, 1: Control device 2: First detection unit 3: Start-up unit 4: Non-defective counter unit 5: Setting unit 6: Comparison unit 7: Second detection unit 8: Second First abnormality command section 9: Defective product counter section 10: Setting section 11: Comparison section 12: Second abnormality command section 13: Cycle counter section 14: Setting section 15: Comparison section M: Injection molding machine

Claims (9)

[Claims] 1. After the automatic operation of the injection molding machine is started, after reaching a stable state, the quality of the molded product is determined by comparing the preset monitor range with the detected physical quantity related to the injection molding operation. In the control method of the injection molding machine that activates the automatic discrimination function to be performed, after the automatic operation is started, the size of the physical quantity obtained for each molding cycle is determined to be the number of times that the physical quantity continuously exists within the monitor range and the continuous monitor range. The number of deviations is detected, and when the number of consecutive occurrences within the monitor range exceeds the preset first target value, the automatic discrimination function is activated, and the number of consecutive deviations from the monitor range is set in advance. An injection molding characterized by outputting an abnormality command signal for executing at least one of operation stop of an injection molding machine or generation of an alarm when the second target value is exceeded. Control method of. 2. When the automatic discrimination function does not start even after the number of molding cycles reaches a preset third target value after the start of automatic operation, at least among the operation stop of the injection molding machine or the alarm generation, The control method of the injection molding machine according to claim 1, wherein an abnormality command signal for executing one or both of them is output. 3. In an injection molding machine having an automatic discrimination function for judging quality of a molded article by comparing a preset monitor range with the size of a detected physical quantity related to the injection molding operation, the automatic operation of the injection molding machine. The first detection unit that detects the number of times the physical quantity obtained in each molding cycle from the start of the number of times that it continuously exists within the monitor range and the second detection unit that detects the number of times that it continuously deviates from the monitor range. In addition, when the number of consecutive occurrences within the monitor range exceeds the preset first target value, the number of consecutive departures from the activation unit and the monitor range that activates the automatic determination function is set to a preset number. A first abnormality command unit that outputs an abnormality command signal that executes at least one of the operation stop of the injection molding machine and the alarm generation when the target value is exceeded. Controller of the injection molding machine, characterized in that. 4. The first detection unit is provided with a non-defective counter unit that counts each molding cycle in which the size of the physical quantity is within the monitor range and resets when the molding cycle is outside the monitor range. The control device for an injection molding machine according to claim 3. 5. The second detection unit is provided with a defective product counter unit for counting for each molding cycle in which the size of the physical quantity is out of the monitor range and for resetting in the molding cycle existing in the monitor range. The control device for the injection molding machine according to claim 3. 6. The starting unit compares the first target value and the detected value output from the non-defective item counter unit with the setting unit for setting the first target value, and when the detected value exceeds the first target value. The control device for an injection molding machine according to claim 3, further comprising: a comparison unit that outputs a start command signal for starting the automatic determination function. 7. The first abnormality command section compares the second target value and the detection value output from the defective product counter section with the setting section for setting the second target value, and the detected value is the second target value. The control device for an injection molding machine according to claim 3, further comprising a comparison unit that outputs an abnormality command signal when the value exceeds the value. 8. When the automatic discrimination function does not start even after the number of molding cycles reaches a preset third target value after the start of automatic operation, at least among the operation stop of the injection molding machine or the generation of an alarm, The control device for an injection molding machine according to claim 3, further comprising a second abnormality command section that outputs an abnormality command signal for executing one or both of them. 9. A second abnormality command section outputs a abnormality command signal when a cycle counter section for counting the number of molding cycles and a detection value output from the cycle counter section exceed a third target value. The control device for an injection molding machine according to claim 8, further comprising a comparison unit.