JP4112552B2 - Temperature control method and controlled object - Google Patents

Description

  The present invention relates to a temperature control method in which a controlled object divided into a plurality of temperature control zones is feedback-controlled by PID control, and more particularly to a method for adjusting the PID constant.

  The temperature control of controlled bodies such as heating cylinders and molding dies of injection molding machines, hot plates of hot presses, and press dies is generally controlled by closed loop control by PID control for each temperature control zone. ing. As is well known, the PID control is proportional control that outputs in proportion to the deviation between the actual measurement value and the control target value, integral control that performs output based on the integral value of the deviation between the actual measurement value and the control target value, and the actual measurement value. And differential control for performing output based on the differential value of the deviation from the control target value. In PID control, it is necessary to set PID constants, which are proportional constants for performing each proportional control, integral constants for performing integral control, and differential constants for performing differential control, to appropriate values. In a controlled body such as a heating cylinder of an injection molding machine, a PID constant that covers basic molding is input as an initial value when the injection molding machine is shipped. However, in reality, there may be cases where accurate temperature control cannot be performed with the PID constants at the time of shipment due to changes in molding conditions such as the material, volume, molding cycle, etc. of the molded product, and changes over time of the machine. It is necessary to readjust.

  The adjustment of the PID constant in each temperature control zone of the controlled body can be performed automatically by auto-tuning or by manually inputting experience values. Patent Document 1 and Patent Document 2 describe performing automatic tuning of a PID constant of a heating cylinder that is a controlled body during molding. However, both of Patent Document 1 and Patent Document 2 simultaneously perform auto-tuning of each temperature control zone of the heating cylinder.

  However, if auto tuning of each temperature control zone of the heating cylinder is performed simultaneously as in Patent Document 1 and Patent Document 2, there is a problem that auto tuning of the intermediate zone and the rear zone of the heating cylinder which is difficult to control temperature cannot be performed accurately. there were. The reason for this will be explained. The intermediate zone of the heating cylinder is a zone where the resin is heated by friction, and both sides are sandwiched between the front zone near the nozzle and the rear zone near the hopper lower part. The temperature that has risen due to heat generation or the like is not easily lowered, and accurate control is difficult. However, if auto-tuning is performed for each temperature control zone at the same time, the temperature in the front and rear zones also rises and falls unstable due to auto-tuning. Tuning is not possible. For the rear zone, the temperature of the supplied resin is lower than the temperature of the heating cylinder, deprives the heat of the rear zone of the heating cylinder, and is adjacent to the lower part of the low-temperature hopper, so that the temperature is stabilized. difficult. However, if auto-tuning of each temperature control zone is performed at the same time, the temperature of the intermediate zone is not stable due to auto-tuning, and the influence also reaches the rear zone, so that accurate auto-tuning of the rear zone cannot be performed.

JP 7-125032 A (Claim 1,0019) JP 2000-218674 A (Claim 1,0004)

  The present invention has been made in view of the above problems, and includes at least three temperatures of a first zone, a second zone, and an intermediate zone in which at least two surfaces are sandwiched between the first zone and the second zone. The present invention provides a temperature control method capable of more accurately adjusting the PID constant of a controlled object divided into control zones.

The temperature control method according to claim 1 of the present invention includes at least three temperature control zones of the first zone, the second zone, and an intermediate zone in which at least two surfaces are sandwiched between the first zone and the second zone. In the temperature control method in which any one of the heated cylinders, molding dies, hot press hot plates, and press dies of the divided injection molding machine is feedback controlled by PID control, only the intermediate zone is first used. And the PID constants of the first zone and the second zone are adjusted simultaneously or before and after .

The temperature control method according to claim 2 of the present invention includes at least three temperature control zones of the first zone, the second zone, and an intermediate zone in which at least two surfaces are sandwiched between the first zone and the second zone. In the temperature control method in which any one of the heated cylinders, molding dies, hot press hot plates, and press dies of the divided injection molding machine is feedback controlled by PID control, only the intermediate zone is first used. The PID constants of the first zone and the second zone are adjusted simultaneously or before and after, and finally the PID constants of the intermediate zone are adjusted again.

  The temperature control method according to a third aspect of the present invention is the temperature control method according to the first aspect, wherein the controlled body is sandwiched between the front zone near the nozzle, the rear zone near the hopper lower part, and the front zone and the rear zone. The heating cylinder of the injection molding machine is divided into at least three temperature control zones of the intermediate zone and is feedback-controlled by PID control.

  A temperature control method according to a fourth aspect of the present invention is the temperature control method according to the second aspect, wherein the controlled object is sandwiched between the front zone near the nozzle, the rear zone near the hopper lower part, and the front zone and the rear zone. A heating cylinder of an injection molding machine that is divided into at least three temperature control zones of the intermediate zone and is feedback-controlled by PID control, first adjusting the PID constant of only the intermediate zone, and then the PID constant of the rear zone And then adjusting the PID constant of the front zone and then adjusting the intermediate zone again.

  A temperature control method according to a fifth aspect of the present invention is characterized in that, in the third or fourth aspect, the PID constant is adjusted at the time of molding or purging.

The controlled body of any one of the heating cylinder and the molding die of the injection molding machine according to claim 6 of the present invention, the hot plate of the hot press, and the press die is any one of claims 1 to 5. According to the procedure of the temperature control method described in item 1, the PID constant of each temperature control zone is automatically adjusted by auto-tuning.

The temperature control method according to the present invention includes an injection molding machine divided into at least three temperature control zones of a first zone, a second zone, and an intermediate zone in which at least two surfaces are sandwiched between the first zone and the second zone. In a temperature control method in which any one of the heated cylinders, molds, hot press hot plates, and press dies is feedback controlled by PID control, the PID constant only for the intermediate zone is first adjusted. Then, since the PID constants of the first zone and the second zone are adjusted simultaneously or before and after , the temperature control of the controlled body can be performed accurately and stably.

  An embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a block diagram showing a heating cylinder and a temperature control device of an injection molding machine according to the temperature control method of the present invention. FIG. 2 is a flowchart of the heating cylinder temperature control method for an injection molding machine according to the temperature control method of the present invention.

  An outline of an injection apparatus 11 in an injection molding machine for forming a disk substrate according to this embodiment will be described with reference to FIG. In the injection device 11, a heating cylinder 13 as a controlled body is attached to a housing 12 that can be moved forward and backward with respect to a fixed plate of a mold clamping device (not shown). A cylinder head 14 is attached to the tip of the heating cylinder 13, and a nozzle 15 is attached to the cylinder head 14. A screw 16 is disposed in the central hole inside the housing 12 and the heating cylinder 13 so as to be able to rotate and move forward and backward, and the rear end of the screw 16 is connected to a measuring servo motor (not shown). The screw 16 is formed with a feed zone, a compression zone, and a metering zone in order from the rear, and a backflow prevention ring 17 is attached to the tip. A hopper 18 is connected to the opening at the top of the housing 12, and resin pellets are supplied into the heating cylinder 13 through the opening. The injection device 11 is provided with an injection servo motor (not shown) so that the screw 16 is driven forward.

  Band heaters 19 are respectively disposed in the heating cylinder 13, the cylinder head 14, and the nozzle 15 in the injection device 11, and a temperature adjustment passage is formed in the hopper lower portion 20 so that a temperature adjustment medium is circulated. The nozzle 15 and the cylinder head 14 are provided with band heaters 19 as independent nozzle zones Z1 and cylinder head zones Z2, respectively, and can be individually feedback controlled by PID control. Moreover, about the heating cylinder 13 which is a to-be-controlled body, the seven band heaters 19 are arrange | positioned by this embodiment. The heating cylinder 13 is heated by the two zone heaters 19 in the vicinity of the front zone Z3, which is the first zone, and the lower portion 20 of the hopper, which is heated by the two zone heaters 19 in the vicinity of the nozzle 15 and the cylinder head 14. The portion to be heated is the second zone, the rear zone Z5, the portion heated by the three central band heaters 19 sandwiched between the front zone Z3 and the rear zone Z5 is divided into intermediate zones Z4, Feedback control is possible by PID control for each temperature control zone Z3, Z4 and Z5. Further, the hopper lower part 20 can also be feedback-controlled by PID control as an independent hopper lower zone Z6. Each temperature control zone Z1 to Z6 is provided with a temperature sensor composed of a thermocouple 21 so that the temperature can be individually detected. The feed zone of the screw 16 corresponds to the hopper lower zone Z6 and the rear zone Z5, the compression zone substantially corresponds to the intermediate zone Z4, and the metering zone substantially corresponds to the front zone Z3. In the present embodiment, the heating cylinder 13 has a front zone Z3, an intermediate zone Z4, and a rear zone Z5 each having one zone and divided into three temperature control zones. At least one of the zone and the rear zone may be further divided into a plurality of temperature control zones. A certain zone in the intermediate zone may be sandwiched indirectly between the front zone and the rear zone via another zone in the intermediate zone.

  Next, the temperature control device 22 of the injection device 11 will be described. The temperature control device 22 includes a temperature signal input unit 23, a control unit 24, a temperature signal output unit 25, a setting input unit 26, a display output unit 27, a storage unit 28, an auto tuning calculation unit 29, and the like. In the temperature signal input unit 23, the temperature data from the thermocouple 21 is A / D converted and captured. In the control unit 24, the temperature signal fetched from the temperature signal input unit 23 is matched with the command value, and calculation is performed using the P constant, I constant, and D constant, and a temperature control signal is generated. In the temperature signal output unit 25, based on the temperature control signal from the control unit 24, an ON / OFF control signal for the current supplied to the band heater 19 and a temperature control device that controls the temperature of the hopper lower part 20. The temperature output signal is output to 32. Therefore, the temperature control device 22 performs closed loop control by PID control of the temperature control zones Z1 to Z6 by the control unit 24 of the temperature control device 22 during normal control other than during auto tuning. In the setting input unit 26, input processing for inputting the set temperature and PID constant for each temperature control zone manually input in the setting input device 30 into the temperature control device 22 and input of an auto-tuning start command are performed. In the display output unit 27, data processing for displaying on the display device 31 is performed. In the storage unit 28, set temperatures of the temperature control zones Z1 to Z6 currently being molded, PID constants for PID control of the band heaters 19 and the like of the temperature control zones Z1 to Z6, and past molding conditions The preset temperature and PID constant are stored. The storage unit 28 stores a sequence program for automatically performing auto tuning.

  In the auto-tuning calculation unit 29, when an auto-tuning start command signal is input from the setting input device 30, the closed-loop control by the control unit 24 is temporarily stopped, and commands and calculations for performing auto-tuning are performed. Is called. The auto tuning procedure will be described next.

  In the injection molding machine for molding the disk substrate of the present embodiment, the resin used is polycarbonate as an example, and the temperature of the injection device 11 is 320 ° C. for the nozzle zone Z1, 350 ° C. for the cylinder head zone Z2, The front zone Z3 of the heating cylinder 13 is set to 350 ° C, the intermediate zone Z4 is set to 330 ° C, the rear zone Z5 is set to 300 ° C, and the hopper lower zone Z6 is set to 100 ° C. When the molding cycle or the set temperature of the injection device 11 is greatly changed due to the change of the molded product, or when a molding defect occurs due to the temperature of the injection device 11, it is necessary to perform auto tuning. Perform auto tuning. In the present embodiment, auto-tuning is performed during molding in which molten resin is injected and filled in a molding die (not shown). The reason for performing auto-tuning during molding is that resin pellets having a temperature relatively lower than the heating cylinder temperature are continuously supplied from the hopper 18 into the heating cylinder 13 at the time of molding. This is because it is necessary to perform PID control of the cylinder 13. On the other hand, since the resin pellets are not supplied when the machine is stopped, the temperature condition is different from that during molding. Note that the disk substrate formed during auto-tuning is not shipped as a product but is discarded or recycled.

  The auto-tuning procedure will be described with reference to the flowchart of FIG. 2. First, an auto-tuning start command is input from the setting input device 30 (S1). Then, the command is sent to the auto tuning calculation unit 29 via the control unit 24, and the auto tuning calculation unit 29 starts calculation processing. The calculation processing in the auto tuning calculation unit 29 is performed based on the auto tuning calculation formula stored in the storage unit 28, the set temperature, and the temperature signal input from the temperature signal input unit 23, and automatically adjusts the PID constant. Is done. Further, regarding the order of the temperature control zones Z1 to Z6 for performing auto tuning, all the temperature control zones Z1 to Z6 of the injection device 11 are automatically tuned automatically in accordance with the order of the sequence program stored in the storage unit 28. Is called. In the present embodiment, first, auto-tuning of only the intermediate zone Z4 is started (S2). At that time, the other temperature control zones Z1 to Z3, Z5 and Z6 are kept in the closed loop control by the conventional PID constant. The reason for starting auto-tuning for only the intermediate zone Z4 is that if auto-tuning is performed simultaneously for each temperature control zone Z1 to Z6, the temperature of the front zone Z3 and the rear zone Z5 becomes unstable due to auto-tuning, This is because the auto-tuning of the intermediate zone Z4 cannot be performed accurately even in the intermediate zone Z4 where temperature control is difficult. Also, if the intermediate zone Z4 is accurately auto-tuned and the temperature is stable, the auto-tuning of the rear zone Z5, which is difficult to control the temperature later, can be performed accurately.

In this embodiment, the adjustment of the PID constant by auto-tuning is performed by the limit sensitivity method. First, the integral operation (I operation) performed using the integral constant for performing PID control and the differential operation (D operation) performed using the differential constant are turned OFF, and only by the proportional operation (P operation) performed using the proportional constant. Allow control. Then, with the output to the band heater 19 in the intermediate zone Z4 of the heating cylinder 13 being 100%, the temperature of the intermediate zone Z4 is raised to the set temperature, and when the set temperature is reached, the energization to the band heater 19 is stopped. Thereafter, the temperature of the intermediate zone Z4 of the heating cylinder 13 rises to a certain level from the set temperature due to overshoot even after the energization is stopped, and eventually falls to approximate the set temperature. At that time, the proportional band P is gradually narrowed. Then, the response of the control amount with respect to the target value gradually becomes oscillating, and eventually starts a constant continuous oscillation exceeding the stability limit. A proportional band in which the constant continuous vibration continues is found, and the proportional band at that time is defined as Pc. The period (time) of the continuous vibration is Tc. The PID constant is obtained by the following formula.

またオートチューニングの方法としては、前記以外にもリミットサイクル法や限界感度法の応用である１／４減衰法を用いても良い。 As a method for obtaining the PID constant in auto-tuning, a known method other than the above-described limit sensitivity method may be used. For example, in the step response method, the control target of the thermal system shows an S-shaped second-order lag element from the response delay, but a tangent is drawn at the inflection point of the S-curve, and the maximum temperature gradient line and time axis The waste time L and the time constant T are obtained from the crossing point. Then, using the waste time L and the time constant T, the PID constant is obtained by the following formula.

As a method for auto-tuning, a 1/4 attenuation method that is an application of the limit cycle method or the limit sensitivity method may be used in addition to the above.

  Then, the PID constant of the intermediate zone Z4 is obtained in about 15 to 20 minutes by the above calculation. When the adjustment of the PID constant by auto-tuning is completed, the PID control of the intermediate zone Z4 is resumed, a waiting time of about 10 minutes is set, and the temperature of the intermediate zone Z4 is approximated to the set value and waits for stabilization. When the waiting time is up (S3), the rear zone Z5 in the vicinity of the lower hopper 20 is then auto-tuned (S4). The auto tuning of the rear zone Z5 is performed in the same manner as the auto tuning of the intermediate zone Z4. At that time, since the auto-tuning of the intermediate zone Z4 has already been completed and the temperature is controlled to a stable temperature, the rear zone Z5 can be accurately auto-tuned.

  Then, the auto-tuning of the rear zone Z5 is completed and the PID control is restarted. When the standby time of about 10 minutes is up (S5), the front zone Z3 (S6), the cylinder head zone Z2 (S8), Auto-tuning is performed in the order of the nozzle zone Z1 (S10) and the hopper lower zone Z6 (S12). The auto-tuning of the front zone Z3 (S6), cylinder head zone Z2 (S8), nozzle zone Z1 (S10), and hopper lower zone Z6 (S12) has a waiting time of about 10 minutes after resuming PID control. Although it is desirable to start by time-up (S7), (S9), (S11), the waiting time is not essential. When the auto-tuning of the hopper lower zone Z6 (S12) is completed and PID control is started and the standby time is up (S13), the intermediate zone Z4 is auto-tuned again (S14). Regarding the reason for auto-tuning the intermediate zone Z4 again, the auto-tuning of the first intermediate zone Z4 was performed before the new auto-tuning of the front zone Z3 and the rear zone Z5. This is because it may not have been done. When the auto-tuning of the intermediate zone Z4 is completed again and PID control is started and the standby time is up (S15), "Auto-tuning end" is displayed on the display screen (S16). Note that auto tuning of the final intermediate zone Z4 is not essential.

  And the temperature of each temperature control zone Z1-Z6 measured after performing auto tuning of each temperature control zone Z1-Z6 of the injection apparatus 11 by the above approximates a setting value, and auto-tunes all the temperature control zones simultaneously. It showed a more stable temperature than that. In particular, the rear zone Z5 is affected by the temperature of the supplied resin pellets, and the temperature is not stable when auto-tuning is performed at the same time, but the problem is solved. The auto-tuning method according to the procedure of this embodiment takes more time than the method of auto-tuning all temperature control zones at the same time, and the resin during that time is sent to recycling or disposal. It seems that there are many. However, since the temperature control of the temperature control zones Z1 to Z6 of the injection apparatus 11 is accurately controlled over a long period of time and the number of defective products is reduced, the cost is eventually reduced.

  Regarding the order of the temperature control zones Z1 to Z6 for performing auto-tuning, the auto-tuning of the intermediate zone Z4 may be performed first, and then only the front zone Z3 may be performed next, or the front zone Z3 and the rear zone Z5. May be performed simultaneously. The nozzle zone Z1 and the cylinder head zone Z2 may be auto-tuned before the intermediate zone Z4 or simultaneously with the intermediate zone Z4. In addition, when there are four or more temperature control zones for the heating cylinder and the intermediate zone (or front zone, rear zone) is composed of a plurality of zones, these zones may be auto-tuned at the same time, or one zone individually. You may perform auto tuning one by one.

  In this embodiment, auto-tuning is performed during molding, but it may be performed at the time of purging when the molten resin in the heating cylinder 13 is discharged. Regardless of whether or not there is resin in the heating cylinder 13, the screw 16 may be stopped and auto-tuning may be performed according to the above procedure. Further, the auto tuning may be performed manually for each temperature control zone Z1 to Z6. Furthermore, the adjustment of the PID constant is not performed by auto-tuning each of the temperature control zones Z1 to Z6, but a part of the temperature control zones may be manually input PID numerical values. For example, when the molding conditions are changed and the PID constants are adjusted again, if only the PID constants of a certain temperature control zone have already been determined to be appropriate values for the molding conditions, The PID constant may be manually input, and the auto-tuning of the intermediate zone Z4 may be performed next while the temperature of the certain temperature control zone is stable. If it is not necessary to change the PID constant even if the molding conditions are changed for a certain temperature control zone, the above-mentioned certain temperature control zone is excluded and only other temperature control zones are auto-tuned. May be.

  In the present embodiment, the heating cylinder 13, the cylinder head 14, and the nozzle 15 of the injection device 11 are described as being heated by the band heater 19. However, for example, as in the injection device of an injection molding machine for thermosetting resin In addition, part or all of the temperature may be controlled by a heat medium such as water or oil. Furthermore, a plunger may be provided inside the heating cylinder instead of a screw. And the molding material used for an injection molding machine is not limited to a resin material, Other materials, such as a metal material and a ceramic material, may be sufficient.

  Next, an example of a molding die of an injection molding machine will be described as another example of a controlled body that is feedback controlled by PID control. FIG. 3 is a view showing a molding die of an injection molding machine according to the temperature control method of the present invention, and is a cross-sectional view of a movable die 41 of a thermosetting resin molding die. The movable mold 41 is provided with a core portion 42 in a central convex shape, and a cavity forming surface 43 is formed on the front surface thereof. Nine cartridge heaters 44 are embedded in the core portion of the movable mold 41, three in each of the upper, middle, and lower stages. The upper cartridge heater 44 heats the first zone ZA that is the peripheral portion. The lower cartridge heater 44 also heats the second zone ZB, which is the periphery. The middle cartridge heater 44 heats the intermediate zone ZC sandwiched between the first zone ZA and the second zone ZB. 3 is a longitudinal section of the center of the mold, only the cartridge heater 44 at the center of the first zone ZA, the cartridge heater 44 at the center of the second zone ZB, and the cartridge heater 44 at the center of the intermediate zone ZC are shown. Has been. Each cartridge heater 44 is connected to a power source by wiring and is PID-controlled by a control device. Also in the movable mold 41, since the intermediate zone ZC is sandwiched between other temperature control zones, it is difficult to dissipate heat to the outside and the temperature does not easily drop. Because it is injection-filled, temperature fluctuation is severe and control is difficult.

  Also in the movable mold 41 of the embodiment shown in FIG. 3, auto-tuning is performed during molding. As a procedure, first, auto-tuning of the intermediate zone ZC of the movable mold 41 is performed. At that time, the PID control is continued in the first zone ZA and the second zone ZB. Therefore, the intermediate zone ZC is accurately auto-tuned because the temperatures of the first zone ZA and the second zone ZB are stable. Then, when the auto-tuning of the intermediate zone ZC is completed and the PID control is resumed, and the predetermined standby time is up, the auto-tuning of the first zone ZA and the second zone ZB is performed simultaneously or before and after. When the auto-tuning of the first zone ZA and the second zone ZB is completed, the PID control is resumed, and the auto-tuning of the intermediate zone ZC is performed again after a waiting time. As a result, the intermediate zone ZC is more accurately auto-tuned. Similarly, the temperature control classification is performed for the fixed mold, and auto-tuning is similarly performed. Needless to say, the temperature control zone is divided into various shapes depending on the shape of the mold. As for the molding die, each temperature control zone may be PID-controlled via a heat medium with a thermoplastic molding die or the like. Moreover, each heater which heats the hot runner part and nozzle part of a thermoplastic molding die may be controlled by PID control. The auto-tuning of the molding die may also be performed when the machine is stopped other than during molding.

  Next, an example of a hot press hot plate will be described as still another example of a controlled body that is feedback-controlled by PID control. FIG. 4 is a view showing a hot platen of a hot press according to the temperature control method of the present invention, in which the hot platen 51 is viewed from the upper surface side. The hot platen 51 is provided with seven through holes 52 in the horizontal direction as indicated by broken lines, and three cartridge heaters 53 are disposed in the respective through holes 52. The three cartridge heaters 53 in one through hole 52 are each connected to a power source by separate wiring and are individually controlled. As shown in FIG. 4, the hot platen 51 is divided into a total of nine zone Za to Zi temperature control zones. In each of the four corner zones Za, Zc, Zg, and Zi of the hot plate 51, two cartridge heaters 53 are provided. Three cartridge heaters 53 are disposed in the first zone Zb between the four corner zones Za and Zc and the second zone Zh between the four corner zones Zg and Zi. Furthermore, two cartridge heaters 53 are disposed in the third zone Zd between the four corner zones Za and Zg and in the fourth zone Zf between the four corner zones Zc and Zi. Three cartridge heaters 53 are disposed in an intermediate zone Ze sandwiched between the first zone Zb and the second zone Zh. The cartridge heater 53 in each temperature control zone Za to Zi is PID controlled to a set temperature by a temperature control device (not shown). However, in the hot plate 51, the intermediate zone Ze is surrounded by the surrounding temperature control zones Za to Zd and Zf to Zi. However, since the laminated body W (indicated by the alternate long and short dash line in FIG. 4) having a relatively low temperature is placed, heat is deprived each time, and temperature control is difficult.

  Therefore, also in the embodiment shown in FIG. 4, only the intermediate zone Ze is first auto-tuned. At that time, since the surrounding temperature control zones Za to Zd and Zf to Zi are not auto-tuned at the same time, the intermediate zone Ze is auto-tuned without being affected by unstable temperature from the surroundings. When the predetermined standby time has expired, auto-tuning of the surrounding temperature control zones Za to Zd and Zf to Zi is performed simultaneously or sequentially. At that time, the first zone Zb, the second zone Zh, the third zone Zd, and the fourth zone Zf may be auto-tuned first from the four corner zones Za, Zc, Zg, and Zi. When the auto-tuning of the surrounding temperature control zones Za to Zd and Zf to Zi is completed, the auto-tuning of the intermediate zone Ze is performed again after a standby time. As a result, the intermediate zone Ze is automatically tuned more accurately. Note that the hot press hot plate is not limited to the temperature control section, for example, a peripheral temperature control zone including the first zone and the second zone, and an intermediate temperature control zone 2 other than that. It may consist of sections. As for the hot press hot plate, each temperature control zone may be individually PID-controlled by a heat medium such as oil.

  Further, the present invention is not enumerated one by one, but is not limited to that of the above-described embodiment, and it goes without saying that the present invention can be applied to those modified by a person skilled in the art based on the gist of the present invention. That is. The controlled body can be applied to various devices as long as each part of the controlled body is individually PID-controlled in addition to the heating cylinder and molding die of the injection molding machine and the hot platen of the hot press.

It is a block diagram which shows the heating cylinder and temperature control apparatus of the injection molding machine which concern on the temperature control method of this invention. It is a flowchart figure of the heating cylinder temperature control method of the injection molding machine which concerns on the temperature control method of this invention. It is a figure which shows the shaping die of the injection molding machine which concerns on the temperature control method of this invention. It is a figure which shows the hot platen of the hot press which concerns on the temperature control method of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Injection apparatus 12 Housing 13 Heating cylinder 14 Cylinder head 15 Nozzle 16 Screw 17 Backflow prevention ring 18 Hopper 19 Band heater 20 Lower hopper 21 Thermocouple 22 Temperature controller 23 Temperature signal input part 24 Control part 25 Temperature signal output part 26 Setting input Unit 27 Display output unit 28 Storage unit 29 Auto tuning calculation unit 30 Setting input device 31 Display device 32 Temperature control device 41 Movable mold 42 Core unit 43 Cavity forming surface 44, 53 Cartridge heater 51 Heat plate 52 Through hole Z1 Nozzle zone Z2 Cylinder head zone Z3 Front zone Z4, ZC, Ze Intermediate zone Z5 Rear zone Z6 Hopper lower zone ZA, Zb First zone ZB, Zh Second zone Za, Zc, Zg, Zi Four corner zone Zd Third zone Zf Fourth zone Laminate

Claims (6)

A heating cylinder and a molding die of an injection molding machine divided into at least three temperature control zones of a first zone, a second zone, and an intermediate zone in which at least two surfaces are sandwiched between the first zone and the second zone In a temperature control method for feedback control of a controlled body of a hot press hot plate or a press die by PID control,
A temperature control method characterized by first adjusting a PID constant of only the intermediate zone and then adjusting a PID constant of the first zone and the second zone simultaneously or before and after . A heating cylinder and a molding die of an injection molding machine divided into at least three temperature control zones of a first zone, a second zone, and an intermediate zone in which at least two surfaces are sandwiched between the first zone and the second zone In a temperature control method for feedback control of a controlled body of a hot press hot plate or a press die by PID control,
First, adjusting the PID constant of only the intermediate zone, then adjusting the PID constant of the first zone and the second zone simultaneously or before and after, and finally adjusting the PID constant of the intermediate zone again. A characteristic temperature control method. The controlled body is divided into at least three temperature control zones: a front zone near the nozzle, a rear zone near the hopper lower part, and an intermediate zone sandwiched between the front zone and the rear zone. The temperature control method according to claim 1, wherein the temperature control method is a heating cylinder of an injection molding machine that is feedback controlled. The controlled body is divided into at least three temperature control zones: a front zone near the nozzle, a rear zone near the hopper lower part, and an intermediate zone sandwiched between the front zone and the rear zone. A heating cylinder of an injection molding machine that is feedback controlled,
3. Adjust the PID constant of only the intermediate zone first, then adjust the PID constant of the rear zone, then adjust the PID constant of the front zone, and then adjust the intermediate zone again. The temperature control method described in 1. The temperature control method according to claim 3 or 4, wherein the adjustment of the PID constant is performed during molding or purging. 6. The injection molding machine according to claim 1, wherein the PID constant of each temperature control zone is automatically adjusted by auto-tuning according to the procedure of the temperature control method according to any one of claims 1 to 5 . A controlled body of any one of a heating cylinder, a molding die, a hot press hot plate, and a pressing die .

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