JPH02208016A - Control device for injection molding processing system - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a molding system for producing precision plastic molded products, and is intended to stabilize the physical properties of the molded product and improve the yield of the molding process. be.

[Conventional technology]

As injection molding processing technology becomes more precise and plastic materials become more sophisticated, the applications of plastic molded products are expanding. In order to produce precision plastic parts, it is essential to control injection molding conditions such as plasticization conditions of molten resin, injection conditions, mold temperature conditions, etc. with good reproducibility. That is, if even one of these conditions fluctuates, a problem arises in that the physical property values of the molded product vary and the molding yield decreases. As a countermeasure against this problem, JP-A-63-15
A control device for an injection molding machine is proposed in Japanese Patent No. 18.

The proposed method continuously monitors molding state quantities such as injection pressure and injection speed in the injection process or filling process, and if these state quantities deviate from set values, the deviation is detected. So-called feedback control is used to make corrections according to the situation.

[Problem to be solved by the invention]

Although the above-mentioned conventional technology strictly controls the molding state quantity, the physical properties of the molded product itself are not taken into account, and molding defects may occur due to the influence of fluctuations in cooling water temperature.
There was a problem that the molding yield decreased.

An object of the present invention is to reduce the above-mentioned variations in physical property values of molded products and to improve molding yield.

[Means to solve the problem]

In order to achieve the above object, the control device of the injection molding processing system of the present invention is equipped with a physical property value measurement block that measures the physical property values of the molded product immediately after molding.

It has the ability to continuously evaluate and monitor the physical property values of molded products.

When changes in the physical properties of these molded products occur due to changes in the working environment, the molding conditions that can most efficiently correct the deviations in the physical properties are corrected and determined.

As a result, it is possible to reduce performance variations from shot to shot.

[Effect]

The controller can continuously grasp the fluctuation behavior of the physical property values of the molded product via the physical property value measurement block.

Further, the physical property value measurement block is configured to be able to control the molding conditions of the injection molding machine via the control block.

Therefore, when the physical property values of the molded product change due to the influence of external disturbances, etc., the injection molding machine is used via the molding block to grasp the fluctuation situation and converge the physical property value of the molded product within the set tolerance range. molding conditions can be adjusted.

〔Example〕

An embodiment of the present invention will be described below with reference to FIG.

FIG. 1 is an explanatory diagram to help understand the outline of the processing system of the present invention. In FIG. 1, reference numeral 1 denotes an injection molding machine, and molding conditions for molding a molded product 2 are set by signals from a control block 3. In FIG.

Molded product 2 released and taken out from the mold after completion of molding
is sent to the measurement block 4, where physical property values such as weight and external dimensions are measured. The physical property items measured by the physical property measurement block 4 and the target values and tolerance values for management are set in advance from the input unit 6 connected to the controller 5. The measured data from the physical property value measurement block 4 is compared with the preset physical property data, and if the deviation is within the allowable range, the control block 3
Outputs only the start signal for the next cycle. −
If the deviation between the force measurement data and the set physical property data exceeds a preset tolerance value, molding is performed to compensate for the deviation based on a correlation data table of the preset physical property values and molding conditions. The condition items and their correction amounts are output to the control block 3. The control block 3 drives a hydraulic sensor J″#, etc. that controls the injection speed or injection pressure of the injection screw based on the control signal from the controller 5, and starts the next cycle after correcting the injection molding conditions.

Similar to FIG. 1, FIG. 2 is a second explanatory diagram that helps in understanding the outline of the processing system of the present invention. Component blocks that are the same as shown in FIG. 1 are numbered the same. In FIG. 2, the controller 5 is connected to a computer 7 having a knowledge database. This knowledge database is an accumulation of data on the relationship between the molding property values of the molded product and the molding conditions, including the interaction of various molding conditions. Further, regarding the resin of the molded article 2, basic physical property values such as pressure dependence and temperature dependence of its flow characteristics are also converted into data.

The controller 5 transfers the measurement data of the physical property measurement block 4 to the computer 7. The computer 7 estimates the cause of the change in the physical property values of the molded product based on a database constructed from the molding data and physical property data. Then, the optimum molding condition items and their correction amounts according to the cause are output to the controller 5. The method of modifying and controlling the molding conditions based on this modification signal is the same as the method described in the previous embodiment. Note that the computer 7 has a function of expanding the knowledge database based on the physical property value observation data transferred from the controller 5.

Next, an embodiment in which the control device of the injection molding processing system of the present invention is applied to the molding processing of plastic lenses will be explained with reference to FIG. It is configured. In other words, this system.

It consists of an abrasive forming machine, a physical property measurement block, a controller computer, and a control block.

In FIG. 3, reference numeral 1 denotes an injection molding machine, which is composed of a mold clamping unit (not shown) for fixing a molding die 8 against injection pressure, a plasticizing injection screw 9°, and a plasticizing cylinder 10. Plasticizing unit 1 for plasticizing and melting materials
1. The injection unit 13 includes a plasticizing injection screw 9 and a hydraulic drive source 12 for driving the plasticizing injection screw 9, and injects and fills molten resin into a mold. 14 is a plastic lens molded from the molding die 8 and the injection molding machine 1. 4
is a physical property measurement block, and the plastic lens 14
Precision balance 15 to measure the weight of, plastic lens 1
Displacement meter 16 for measuring the outer diameter of 4. Displacement meter 17.18 that measures the so-called sag amount, which is the displacement of the lens surface at a specific position in the radius with respect to the center of the plastic lens.
(The displacement gauges 17 and 18 are two independent displacement gauges, each measuring a specific surface.)

A point micrometer 19 for measuring the wall thickness at the center and the edge of the plastic lens 14; an image processing unit 20 for observing the occurrence of internal stress using polarized light; and the precision balance 15. Displacement meter 16.17.18. The point micrometer 19° is composed of a data recording unit 21 that converts the measurement value of the image processing unit 20 into an electrical signal and transfers the measurement to the controller 5. 5
6 is a controller, 6 is an input crab, and 7 is a computer, the functions of which are the same as those explained in the embodiment of FIG. 2 above. 3 is a molding condition control block, and includes an injection filling condition control unit 25 which controls the injection filling conditions of the injection pressure cover turn and the injection speed pattern through the injection unit 13. Plasticizing injection screw9. Plasticizing cylinder 1
The plasticizing condition control unit 24 controls the temperature pattern of the heating cylinder, the number pattern of the plasticizing injection cylinder, the back pressure pattern, and the plasticizing amount through the mold temperature controller 27. A mold temperature control unit 23 that controls the mold temperature conditions of the temperature pattern of the mold 8. The compression pressure of the molten resin is applied via the compression unit 26, which is composed of a compression cylinder (not shown) built into the molding die 8 and a hydraulic unit.

It is composed of a compression condition control unit 22 that controls compression conditions such as the amount of compression and the compression speed.

The configuration of the mold temperature controller 27 will be further explained with reference to FIG.

The mold temperature controller 27 has a high temperature unit 28° and a low temperature unit 2.
Equipped with two types of heat carriers (9). The high temperature unit 28. The low temperature unit 29 has switching valves 31oL, 316
It is connected to the molding die 8 via the heating medium controller 30 and centrally controlled by the heat medium controller 30. The heat medium controller 30 selectively supplies a high temperature heat medium and a low temperature heat medium to the molding mold in accordance with the injection molding process, controls the flow rate of the heat medium, and controls the temperature pattern of the mold 8. are doing. Further, the heat medium controller 30 is configured to be directly controlled by the mold temperature control unit 23.

The operation of the control device of the injection molding system configured above will be described as a specific example of injection molding a convex lens using acrylic resin as the lens material.

The injection mold 8 is controlled by a temperature controller 27 according to a mold temperature pattern shown in FIG. The molten resin at 220°C plasticized and melted in the injection molding machine 1 is transferred to the molding die 8 at 150°C.
injection filling. The injection filling conditions are controlled via the injection molding condition control unit 25 and the injection unit 13.

The molten resin injected into the mold 8 is cooled and solidified by heat exchange with the mold 8 having the mold temperature pattern shown in FIG. 5, and is shaped into a lens shape, released from the mold, and taken out. The plastic lens 14 was taken out.

It is transported to the physical property value measurement block 7, and its weight is measured by the precision balance 15. Similarly, the displacement meter 16 measures the outer diameter of the lens, the displacement meters 17 and 18 measure the amount of sag on both surfaces of the lens, and the point micrometer 19 measures the thickness of the lens center and the edge portion. Further, the image processing unit 28 measures the state of occurrence of internal stress. These measured and observed results are transferred to the controller 5 via the data recording unit 21. The controller 5 compares the data transferred from the recording unit 21 with the physical property data set from the input unit 6 and the standard value. If the deviation between the two is also within the tolerance range set at the input unit 6, the controller 5 is molding condition control block 3
Outputs only the start signal for the next cycle. The molding condition control block 3 that received this start signal controls the plasticizing condition control unit 24. Mold temperature control unit 23
At the same time, a cycle start signal is sent to the injection filling condition control unit 25 and the compression condition control unit 22, and the cycle of the injection molding machine 1 is started.

The standard deviation between the measurement data of the plastic lens 14 transferred from the recording unit 21 and the physical property data set from the input crab unit 6.

If the allowable range is exceeded, the controller 5 outputs a molding condition correction signal to the molding condition control block 3. For example, out of the measurement data of the plastic lens 14, 9 deviations in weight and deviations in outer diameter are acceptable. If the value falls below the lower limit, the controller 5 transfers this data to the computer 7. The computer 7 refers to the weight, outer diameter dimensions, and molding conditions in the knowledge database and deduces that an abnormality has occurred in the molding conditions of the filling process. Furthermore, the data on the basic performance of acrylic resin was used to find a correction method for correcting the deviation, and the most effective correction method was to increase the injection pressure in the final filling process of the injection pressure cover to a certain value. reason. This information is then transferred to the controller 5.

The controller 5 changes the setting value of the injection pressure for the final filling process in the injection filling condition control unit 22 of the molding condition control block 3, and performs feedback control of the injection unit 13 to realize the fixed value. As a result, the weight deviation and the outer diameter deviation fall within permissible ranges, and the stability of the physical properties of the plastic lens 14 is ensured.

Further, in the measurement data of the plastic lens 14, if the deviation of the sag amount exceeds the allowable value on both sides, the computer 5 transfers this data to the computer as in the above example. Computer 5 calculates that since the deviation amount is almost the same value on both sides and the direction of the displacement is the same,
It is determined that warpage deformation has occurred, and the relationship between warp deformation and molding conditions is checked in the knowledge database. As a result, it was inferred that an abnormality in the filling process and cooling process was the cause of the warpage.

It is inferred that the most effective correction method would be to individually correct the temperature of the mold forming each surface of the plastic lens 14. This information is then transferred to the controller 5. The controller 5 modifies the mold temperature set values for the filling process and cooling process in the mold temperature control unit 23 of the molding condition control block 3. The mold temperature control unit 23 adjusts the flow control valves of the high temperature unit 28 and the low temperature unit 29 via the heat medium controller 30.

The flow rate of the heat medium supplied to the molding die 8 is controlled.

The mold temperature can be corrected by a correction instruction from the controller 5. As a result, the amount of warp deformation converges to an allowable range, and the stability of the physical property values of the plastic lens 14 is ensured.

Next, an embodiment in which the present invention is applied to the molding process of optical disks will be explained with reference to FIG. 6. The system has almost the same configuration as that shown in FIG. They are equipped differently. The reject unit 32 has a function of discharging from the production line molded products that the computer 7 estimates to be defective based on a reject signal from the controller 5.

The operation of the control device of the optical disk molding system configured as described above will be described as a specific example of injection molding using polycarbonate resin as a material. The basic process of injecting and filling the plasticized molten resin from the injection molding machine 1 into the molding die 8, cooling and solidifying the molten resin by heat exchange with the molding die 8, and shaping it is shown in FIG. It is similar to

Further, the response when the deviation between the measurement data of the optical disc 33 transferred from the recording unit 21 and the set standard value exceeds the permissible range is the same as that shown in FIG. 3 above.

Since the feature of this embodiment lies in the reject unit 32, its operation will be mainly explained.

For example, among the measurement data of the optical disc 33.

If the internal stress deviation shows a large value exceeding the permissible value, this data is transferred to the computer 7. The computer 7 refers to the relationship between the occurrence of internal stress and the molding conditions in the knowledge database and deduces that excessive filling strain has occurred. This molded optical disc 33 is determined to be a defective product, and a reject signal is sent to the reject unit 32 of the molding condition control block 3 via the controller 5. Receive the reject signal or reject unit 3
2 transports the optical disc 33 determined to be a defective product to a defective product disposal box 34. As a result, the defective optical disc 33
can be prevented from being input into the production line and reducing the yield of the secondary process.

Furthermore, the computer 7 refers to the basic physical properties of the flow characteristics of polycarbonate resin based on its knowledge, and determines the most effective way to increase the mold temperature during filling of the mold 8 and adjust the injection pressure cover turn and injection speed pattern. I infer that this is a corrective method.

This information is then transferred to the controller 5. The method by which the controller 5 modifies the molding conditions via the molding condition control block 3 is the same as in the previous embodiment. This ensures the stability of the physical property values of the optical disc 33, and
It becomes possible to eliminate defects that occur during the molding process.

〔Effect of the invention〕

As explained above, according to the present invention, it is possible to directly monitor the physical property values of an injection molded product and modify and control the molding conditions based on that information. As a result, the quality of the molded product is stabilized, and the molding yield can be improved by 30% or more compared to the conventional technology. Furthermore, it is now possible to check for molding defects and, in the unlikely event that a defective product occurs, it is possible to discard the defective product from the production line. Therefore, it is possible to send defective molded products to the next process and prevent the accumulation of defective man-hours as in the conventional method. As a result, the efficiency of the entire manufacturing process can be significantly improved.

[Brief explanation of the drawing]

FIG. 1 is a block diagram explaining the present invention in detail, and FIG. 2 is a block diagram schematically explaining another embodiment of the present invention. Fig. 3 is an explanatory diagram of an embodiment in which the present invention is applied to molding processing of plastic lenses, Fig. 4 is a configuration diagram illustrating a mold temperature controller in the embodiment of Fig. 3, and Fig. 6 is an explanatory diagram of an embodiment in which the present invention is applied to molding processing of plastic lenses. FIG. 2 is an explanatory diagram of an embodiment applied to molding of an optical disk. Fifth
The figure is an explanatory diagram of a mold temperature pattern by the mold temperature controller shown in FIG. 3. 1... Injection molding machine. 2... Molded product. 3... Molding condition control block. 5... Controller. 4...Physical property value measurement block. 7...Computer Accumulation 1 Figure 2: A preliminary diagram of the family tree. outline

Claims (1)

[Claims] 1. In an injection molding processing system that processes a molded product (2) by injecting and filling a plasticized molten resin into a molding die (8), Physical property measurement block (4) that measures the performance of the molded product (2) immediately after being molded
and a controller (5) that compares the measurement data of the physical property value measurement block (4) with the set value of the performance of the molded product (2) and outputs a correction signal according to the deviation.
) and an injection molding machine (1) equipped with a molding condition control block (3) that can modify molding conditions according to the output signal of the controller (5). Device. 2. In the injection molding processing system according to claim 1, the controller (5) is connected to a computer (7) having a knowledge database constructed from the correlation between the performance of the molded product (2) and the molding conditions, and (2) When the physical property value deviates from the preset tolerance range and a molding defect occurs, the cause of the occurrence is estimated and a signal indicating the modification factor and amount of modification of the molding conditions is sent to injection molding according to the cause. A control device for an injection molding processing system characterized by outputting information to a machine (1) and continuously maintaining appropriate conditions. 3. In the injection molding processing system according to claim 1, a physical property value measurement block (4) for measuring the performance of the molded product (2) is provided.
) is a precision balance (15) that measures the weight of the plastic lens (14), and a displacement meter (15) that measures the outer diameter of the plastic lens (14).
16), Displacement meter (17), (18) that measures the so-called sag amount, which is the deformation of the lens surface at a specific position in the radius with respect to the center of the plastic lens (14). A plastic lens characterized by comprising a point micrometer (19) for measuring the thickness and edge portion thickness, and an image processing unit (20) for observing the occurrence of internal stress in the plastic lens (14) using polarized light. Control device for injection molding processing system. 4. In the injection molding processing system according to claim 1, the molding condition control block (3) that controls the molding conditions comprises an injection condition control unit (3) that controls the injection speed and injection pressure.
25), a plasticizing condition control unit (24) that controls the plasticizing cylinder temperature, screw rotation speed, and screw back pressure, a mold temperature control unit (23) that controls the molding mold temperature
, characterized by comprising a compression condition control unit (22) that controls the compression pressure, compression amount, and compression speed for pressurizing and compressing the molten resin inside the molding die (8) after filling with the molten resin. Control device for plastic lens injection molding processing system. 5. A mold temperature control unit (23) selectively supplies a high-temperature heat medium and a low-temperature heat medium to the mold (8) according to the molding process, and controls the flow rate and temperature of the heat medium. A temperature controller body that controls the temperature pattern of the molding die (8), and a set value of the flow rate of the heat medium, a set value of the heat medium temperature, and switching between high temperature and low temperature heat medium by signals from the controller (5). 4. The control device for a plastic lens injection molding processing system according to claim 3, further comprising a mold temperature condition control section that corrects timing set values. 6. Based on the information input from the physical property measurement block (4) that measures the performance of the molded product (2), the computer (7
) refers to the knowledge database and determines that the molded product (2) is defective, the controller (5) outputs a defective product reject signal to the molding condition control block (3) and rejects the molded product. The determined molded product (
2) A control device for an injection molding processing system characterized by rejecting the above from the production line.