JP3703670B2 - Hot press control method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a program control method for temperature and pressure of a hot plate in a hot press in which a plurality of hot plates are temperature-controlled at a predetermined temperature and pressed with a predetermined pressure to form a molded product, particularly a laminated molded product.
[0002]
[Prior art]
In a hot press for forming a molded product such as a laminated plate, closed loop control of PID is generally performed by a so-called program controller that sets and controls temperature and pressure in stages with respect to a time axis. The temperature control by the program adjuster sets and controls the temperature of the hot plate, not the temperature of the molded product. Therefore, since it was not possible to directly know whether the molded product was sufficiently heated or cooled, the length of the time axis of one control segment, which is one control period of temperature (pressure), has conventionally been sufficient. It was customary to set longer to see.
[0003]
[Problems to be solved by the invention]
Therefore, in the control by the conventional method as described above, as a result of setting the time axis of one control segment to be long, even if the actual temperature of the molded product reaches the ideal hot plate temperature, it is still heated (cooled). By continuing to do so, the thermal history of the molded product becomes excessively long, leading to deterioration of the quality of the molded product, or delaying the molding cycle. On the other hand, as a result of setting the time axis of one control segment to be short, the program controller shifts to the next control segment before the temperature of the molded product reaches the temperature of the hot plate, and gives a sufficient amount of heat to the molded product. Or the molded product cannot be cooled sufficiently, resulting in deterioration of the quality of the molded product.
[0004]
[Means for Solving the Problems]
Where the control method of the hot press of the present invention, hot to the program control in each control segment Sn, and controls the hot plate temperature to match the preset temperature, a molded article was clamped at a predetermined pressure In the press, when the internal temperature of the molded product in each control segment Sn reaches the hot plate temperature, the process proceeds to the next control segment Sn + 1 , and even if the time axis of the control segment Sn ends, When the internal temperature does not reach the hot plate temperature, the time axis of the control segment Sn is extended .
[0005]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a graph showing an example of the relationship between the measured value (solid line) of the hot plate temperature in the program controller 7 and the measured value (broken line) of the temperature of the molded product based on the present invention. FIG. 2 is a block diagram showing a part of a hot press mechanism, a temperature control loop of a hot plate, and a signal flow with the device of the control device according to the present invention. FIG. 3 is a flowchart showing the control method of the present invention.
[0006]
Reference numeral 1 denotes a hot plate, in which a molding material of a laminated molded product 3 sandwiched between mirror plates 2 is installed between a plurality of hot plates 1 arranged at equal intervals. The space between the hot plates 1 is reduced by a not-shown pressing device to compress the molding material, and the molding material is molded as a molded product 3 by the heat quantity of the temperature-controlled hot plate 1. The temperature control of the hot plate 1 is executed by the program controller 7. The temperature of each hot plate 1, 1 is detected by hot plate temperature sensors 5, 5, and each detected hot plate temperature signal is input to the program controller 7. In the program controller 7, the temperature setting value that changes with the passage of time of the preset temperature and the hot plate temperature signal are matched, the deviation is calculated by PID or the like, and the hot plate temperature signal is the temperature set value. The temperature control signal 8 is output to the temperature control device 11 that heats or cools the hot plate 1 so as to coincide with. The temperature control device 11 heats or cools the medium to be circulated through the hot plate 1 according to the temperature control signal 8. Although not shown, the program control of the pressing force of the hot plate 1 shares a time axis with the temperature program control.
[0007]
In order to detect the internal temperature of the molded product 3, a plurality of molded product temperature sensors 4 are inserted into the molding material for each stage of the hot plate 1. The molded product temperature sensor 4 is composed of thin thermocouple strands, arranged at the key points of the laminated molding material at the mechanical stage, leading the lead wire to the end of the molding material, and connecting with a connector if necessary The molded product temperature signals t _{1 to} t _n obtained by relaying are input to the control device 6. The control device 6 may be a part of a sequencer that controls the hot press or may be prepared exclusively. The controller 6 also receives a temperature signal 9 of the hot plate temperature from the program controller 7. The control device 6 performs processing as shown in the flowchart of FIG. 3 to shorten or extend the time axis of the control segment in the program adjuster 7 and output a correction signal 10 for shifting the time axis of the control segment. .
[0008]
Next, a control method will be described with reference to FIG. In the flow F1, the setting of whether or not the correction control of the present invention is to be executed is seen in each control segment Sn of the program controller 7, and if it is NO, all processing is stopped. If yes, go to Flow F2 to see if the control mode is AND or OR. When the control mode is AND, by calculating the average value of the molded article temperature signal t ₁ ~t _n see if it has reached the value of the temperature signal 9 of the hot plate temperature (Tn) (flow F3). When the average value of t _{1 to} t _n does not reach Tn, if the time is within the time axis of the control segment Sn, the process returns to the flow F3, and if the time is the end of the time axis of the control segment Sn, the control is performed. After extending the time axis of the segment Sn, the flow returns to the flow F3 (flows F4 and F5). When the average value of t ₁ to t _n reaches Tn in the flow F3, the control segment Sn is shifted to the next control segment Sn + 1 (flow F9).
[0009]
In the flow F2, when the control mode is the OR, see if any one point of the molded article temperature signal t ₁ ~t _n has reached the value of the temperature signal 9 (Tn) of the hot plate temperature (flow F6 ). When none of t _{1 to} t _n has reached Tn, if the time is within the time axis of the control segment Sn, the process returns to the flow F6, and if that time is the end of the time axis of the control segment Sn, the control segment After extending the Sn time axis, the flow returns to the flow F6 (flows F7 and F8). When any _one of t ₁ to t _n reaches Tn in the flow F6, the control segment Sn is shifted to the next control segment Sn + 1 (flow F9).
[0010]
In the graph shown in FIG. 1, as an example of the above control method, the time axis is a control segment from S1 to S4, and the temperature signal 9 of the hot plate in each control segment is controlled from T1 to T4 indicated by a solid line. Indicates the state. Here, the broken line is one point or an average value of the molded product temperature signal which is the temperature of the molded product. During the control of the control segment S2, the molded product temperature signal reaches the hot plate temperature signal T2 at 21, and the control segment S2 is controlled at the start of the control segment S3 indicated by 20 by the processing of YES in the flow F3 or the flow F6. Move by shortening the time axis of segment S2.
[0011]
In the control segment S3, since the molded product temperature signal does not reach the hot plate temperature signal T3 at the end point 22, the time axis of the control segment S3 is obtained by the processing of the flows F4 and F5 or the flows F7 and F8. , And at the time 23 when the temperature signal of the molded product reaches the temperature signal T3 of the hot plate, the process proceeds to the next control segment S4.
[0012]
【The invention's effect】
Since the present invention is configured as described above and the control segment is automatically shifted when the temperature of the actual molded product reaches the temperature of the hot plate, the thermal history of the molded product can be minimized or molded. It can give enough heat to the product, improve the quality of the molded product and optimize the molding cycle to improve the production efficiency of the laminated molded product.
[Brief description of the drawings]
FIG. 1 is a graph showing an example of a relationship between an actual measurement value (solid line) of a hot plate temperature and an actual measurement value (broken line) of a temperature of a molded article based on the present invention.
FIG. 2 is a block diagram showing a part of a hot press mechanism, a temperature control loop of a hot plate, and a signal flow with the device of the control device according to the present invention.
FIG. 3 is a flowchart showing a control method of the present invention.
[Explanation of symbols]
1 ……… Heat plate 2 ……… Mirror plate 3 ……… Molded product 4 ……… Molded product temperature sensor 5 ……… Hot plate temperature sensor 6 ……… Controller 7 ……… Program controller 8… … Temperature control signal 9 ……… Temperature signal 10… Correction signal 11… Temperature controller

Claims (2)

In each control segment Sn, the hot plate temperature is controlled by a program controller so as to match a preset temperature, and the molded product is molded by pressing with a predetermined pressure. When the internal temperature reaches the hot plate temperature, the process proceeds to the next control segment Sn + 1 , and the internal temperature of the molded product has reached the hot plate temperature even when the time axis of the control segment Sn is completed. A hot press control method characterized by extending the time axis of the control segment Sn when there is not .   The method of controlling a hot press according to claim 1, wherein the internal temperature is one of a plurality of internal temperatures or an average value of the plurality of internal temperatures.

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