Heating control method and device for injection molding machine

Abstract

The present invention provides a heating control method and apparatus for an injection molding machine, in which a heating unit (2) that can be adapted to the amount of power of a power supply voltage that is allowed to be used in any use location is selected in advance and assembled to an injection molding machine (M), and when the injection molding machine (M) is installed in the use location, the heating unit (2) is configured to heat the injection molding machine (M). A molding machine controller (3) of an injection molding machine (M) directly or indirectly acquires and processes a power supply voltage in a power supply (Po) as an actual power supply voltage (Vp), and calculates and processes an energization gradient rate (Rc) based on a ratio between the actual power supply voltage (Vp) and a rated voltage (Vs) of a heating unit (2) of the injection molding machine (M) as a conversion coefficient (Kc). The power supply (Pu) to the heating unit (2) is controlled by a power distribution process in which the conversion coefficient (Kc) is multiplied by a control amount (Cs) to the heating unit (2).

Description

Technical Field

[0001] The present invention relates to a heating control method and apparatus for an injection molding machine, which are preferably used when adapting an injection molding machine to a power supply source for supplying power to the injection molding machine. Background Art

[0002] Generally, injection molding machines are installed and used in molding factories and the like in various regions of the world, including in the country. In this case, the voltage of the power supply source for supplying power to the injection molding machine varies depending on the power supply standard in the region, and voltages in the range of approximately 200V - 480V are used. Therefore, when manufacturing an injection molding machine, it is designed to be suitable for the voltage of the region where it is to be installed. Specifically, the rated voltage of the belt heater (heating unit) installed in the heating cylinder is selected to avoid any mismatch with the region where it is to be installed at the time of factory shipment. However, in reality, there are many cases where the power supply voltage is different during actual installation depending on the usage environment and the like. As a result, in such cases, it is necessary to replace the heating unit (belt heater) installed in the injection molding machine to cope with it, which causes problems such as wasted installation time and unnecessary costs.

[0003] On the other hand, countermeasures have also been proposed on the injection molding machine side to cope with different power supply voltages without replacing the heating unit. The applicant has already proposed a temperature control method for an injection molding machine that can address this issue through Patent Document 1.

[0004] Regarding the temperature control method of Document 1, in the case of producing molded products (products) by an injection molding machine, there are many cases of multi-variety and small-batch production, and it is necessary to frequently perform production switching, that is, to frequently switch molding conditions such as heating temperatures mainly for the mold. Therefore, for the purpose of addressing this issue, specifically, a heating unit or a cooling unit is attached to the temperature control target part to be temperature-controlled for heating or cooling, and the heating unit or the cooling unit is controlled so that the temperature of the temperature control target part becomes a preset target temperature. In the temperature control method of the injection molding machine, the temperature control ability during the rising period and the temperature control ability during the molding period are set by the supply power supplied to the heating unit or the cooling unit. When switching from the temperature control ability during the rising period to the temperature control ability during the molding period, the supply power is distributed through power distribution processing. As the power distribution processing, it is performed by a waveform thinning process in which a part of the AC waveform is removed (remove).

[0005] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2022 - 127229

[0006] On the other hand, the temperature control method of the injection molding machine in the above Patent Document 1 also has the following problems to be solved.

[0007] That is, since each temperature control capacity is set according to the power supplied to the heating unit, and the switching of each temperature control capacity is performed by a power distribution processing that distributes the supplied power, specifically, a power distribution processing based on a waveform thinning processing that removes a part of the AC waveform, as an advantage of the power distribution processing, each temperature control capacity can be easily generated (selected), and control and implementation can be facilitated without using a large-scale transformer unit or a current converter unit, thereby enabling the device to be miniaturized.

[0008] However, there has been a demand for improvement measures to effectively address the problem of not being able to cope with different external power supply voltages that are a power supply source for the injection molding machine when the injection molding machine is moved to various regions (delivered). Summary of the invention

[0009] In order to solve the above-mentioned problems, the heating control method of the injection molding machine of the present invention is characterized in that, when making the injection molding machine M suitable for the power supply source Po for powering the injection molding machine M, a heating unit 2 that is suitable for the amount of power of the power supply voltage that can be imagined in any place of use is pre-selected and assembled to the injection molding machine M, and when the injection molding machine M is set at the place of use, the power supply voltage in the power supply source Po is directly or indirectly obtained and processed as the actual power supply voltage Vp through the molding machine controller 3 possessed by the injection molding machine M, and the conduction gradient rate Rc based on the ratio of the actual power supply voltage Vp to the rated voltage Vs of the heating unit 2 possessed by the injection molding machine M is calculated and processed as a conversion coefficient Kc, and the power supply Pu to the heating unit 2 is controlled by multiplying the conversion coefficient Kc by the power distribution processing of the control amount Cs of the heating unit 2.

[0010] And, for the above problems, the heating control device 1 of the injection molding machine of the present invention is characterized by having: a heating unit 2, which is assembled to the injection molding machine M by being selected to be suitable for the amount of electric power of the power supply voltage that can be conceived in any place of use when constituting the heating control device for the power supply Po that supplies power to the injection molding machine M; and a molding machine controller 3, which includes an actual power supply voltage acquisition function unit Fd, a conversion coefficient calculation function unit Fc, and a supply power control function unit Fp. The actual power supply voltage acquisition function unit Fd directly or indirectly acquires and processes the power supply voltage in the power supply Po as the actual power supply voltage Vp. The conversion coefficient calculation function unit Fc calculates and processes the conversion coefficient Kc by calculating the conduction gradient rate Rc based on the ratio of the actual power supply voltage Vp to the rated voltage Vs of the heating unit 2 possessed by the injection molding machine M. The supply power control function unit Fp has a power distribution processing unit Fpd, and the power distribution processing unit Fpd controls the supply power Pu to the heating unit 2 by performing power distribution processing on the control amount Cs of the heating unit 2 by multiplying the conversion coefficient Kc.

[0011] On the other hand, in a preferred embodiment of the present invention, when implementing the heating control method, the actual power supply voltage Vp can be indirectly acquired and processed from the DC voltage Ed in the drive circuit 12 that drives the actuators 11a... built in the injection molding machine M. And the power distribution processing can be performed by performing waveform thinning processing on a part of the AC waveform W based on the conversion coefficient Kc, and this waveform thinning processing can be performed by multiplying the control amount Cs by the conduction gradient rate Rc. In addition, the control amount Cs can be the output operation amount MV in the PID control system C in which a prescribed PID constant is set. On the other hand, when implementing the heating control device 1, a display 13 for displaying at least one of the actual power supply voltage Vp, the rated voltage Vs, and the conduction gradient rate Rc can be set in the molding machine controller 3, and an output limiter 14 for limiting the conversion coefficient Kc to not exceed 100% can be provided in the molding machine controller 3. In addition, at least one strip heater 15n... can be included in the heating unit 2.

[0012] According to the heating control method and device 1 of the injection molding machine M of the present invention as described above, the following remarkable effects are achieved.

[0013] (1) Since the power distribution function that distributes and outputs power through power distribution processing is used, as an advantage of the power distribution processing, it is possible to simplify the control and implementation without using large-scale voltage transformation units and current transformation units, and furthermore, it is possible to miniaturize the device. In particular, when the injection molding machine M is moved (set) to an area with various power supply voltages, even in a state where the power supply Po, the power supply voltage, and the rated voltage Vs of the heating unit 2 of the injection molding machine M are not suitable, the injection molding machine M can be directly set without replacing the heating unit 2 such as a belt heater, etc., and it is possible to avoid problems of wasting unnecessary setting time and generating unnecessary costs. Also, as long as one heating unit with an appropriate power capacity is selected, it is also possible to enjoy the secondary effect that the injection molding machine, etc., manufactured in advance can be stored, which can improve the degrees of freedom in design and production.

[0014] (2) In a preferred manner, when implementing the heating control method, if the actual power supply voltage Vp is indirectly obtained from the DC voltage Ed in the drive circuit 12 that drives the actuators 11a... built in the injection molding machine M, it can be implemented without adding another voltage detection unit, so it can contribute to cost reduction and miniaturization.

[0015] (3) In a preferred manner, if the power distribution processing is performed by the waveform thinning processing that thins out a part of the AC waveform W based on the conversion coefficient Kc, the AC waveform W can be changed (distributed) by time-sharing processing, so it can be easily implemented without accompanying the complication and enlargement of the control system.

[0016] (4) In a preferred manner, if the output operation amount MV in the PID control system C with a specified PID constant set is used as the control amount Cs, since the PID control system C for the temperature during molding is used, stable and reliable control can be performed.

[0017] (5) In a preferred manner, when implementing the heating control device 1, if a display 13 that displays at least one of the actual power supply voltage Vp, the rated voltage Vs, and the power-on gradient rate Rc through a screen is provided in the molding machine controller 3, the operator can visually confirm the indirectly obtained actual power supply voltage Vp, the rated voltage Vs, and the calculated power-on gradient rate Rc, so it is possible to supply an appropriate voltage (power), and it is easy and reliable to grasp whether appropriate control has been performed.

[0018] (6) In a preferred manner, when implementing the heating control device 1, if an output limiter 14 that limits the conversion coefficient Kc to not exceed 100% is set in the molding machine controller 3, it is particularly possible to avoid the generation of excessive power. Therefore, it is possible to avoid heater disconnection and the like, achieve the protection of the injection molding machine M, and contribute to the further improvement of safety and reliability.

[0019] (7) In a preferred manner, if at least one belt heater 15n… is included in the heating unit 2, it can be used for the heating control of the heating cylinder, which is the most important heating part in the injection molding machine M. Therefore, it can also contribute to the stabilization of the operation of the injection molding machine M and further contribute to the improvement of the molding quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a flowchart showing the processing steps of the heating control method for the preferred embodiment of the present invention.

[0021] Figure 2 It is a schematic overall structure diagram of an injection molding machine having the heating control device of the preferred embodiment of the present invention.

[0022] Figure 3 It is a front structure diagram of the belt heater of the injection molding machine.

[0023] Figure 4 It is a list showing the relationship between the rated voltage of the belt heater of the injection molding machine and the corresponding current gradient rate.

[0024] Figure 5 It is a schematic circuit diagram of the drive circuit of the actuator of the heating control device.

[0025] Figure 6 It is a current waveform diagram output from the power distribution processing unit of the heating control device.

[0026] Figure 7 It is a modified current waveform diagram output from the power distribution processing unit of the heating control device.

[0027] Figure 8 It is a basic setting screen diagram of the display of the heating control device.

[0028] Figure 9 It is a circuit block diagram in the PID control system including the power distribution processing unit of the heating control device.

[0029] REFERENCE NUMERAL DESCRIPTION

[0030] 1: Heating control device; 2: Heating unit; 3: Molding machine controller; 11a…: Actuator; 12: Drive circuit; 13: Display; 14: Output limiter; 15n…: Belt heater; M: Injection molding machine; Po: Power supply; Pu: Supplied power; Vp: Actual power supply voltage; Vs: Rated voltage; Rc: Passing elevator gradient rate; Kc: Conversion coefficient; Cs: Control quantity; MV: Output operation quantity; Fd: Actual power supply voltage acquisition functional unit; Fc: Conversion coefficient calculation functional unit; Fpd: Power distribution processing unit; Fp: Supplied power control functional unit; Ed: DC voltage; W: AC waveform; Wh: Half wave; Wf: Full wave. Detailed implementation mode

[0031] Next, preferred implementation modes of the present invention will be listed and described in detail based on the drawings.

[0032] First, refer to Figure 2 ( Figure 3 、 Figure 8 and Figure 9 ) to describe the structure of the injection molding machine M capable of implementing the heating control method of this implementation mode.

[0033] Figure 2 The injection molding machine M, particularly the injection device Mi omitting the mold (clamping device), is shown, and the drive control system Ms for driving and controlling various actuators of the injection molding machine M is shown.

[0034] In the injection device Mi, 21 is a heating cylinder, and an injection nozzle 21n is provided at the front end of the heating cylinder 21 via a head 21e. In addition, a hopper 21h for storing a molding material (resin material) 21r is provided at the rear end of the heating cylinder 21, and the lower end opening of the hopper 21h communicates with the inside of the heating cylinder 21 via a material dropping passage.

[0035] Thus, the molding material 21r in the hopper 21h is supplied into the heating cylinder 21 through the material dropping passage. In addition, a screw 22 is rotatably and reciprocally loaded in the heating cylinder 21, and the rear end of the screw 22 is coupled to a screw drive unit 23. The screw drive unit 23 has a screw rotation mechanism 23r for rotating the screw 22 and a screw reciprocating mechanism 23m for advancing or retracting the screw 22. In the illustrated case, the drive methods of the screw rotation mechanism 23r and the screw reciprocating mechanism 23m are electric drive methods using an electric motor. As the drive method, a hydraulic drive method using a hydraulic circuit or the like may also be used, and the drive method is not limited.

[0036] On the other hand, the screw rotation mechanism 23r and the screw advance / retreat mechanism 23m are connected to the controller main body 26 of the molding machine controller 3. Thus, a control command for driving and controlling the screw rotation mechanism 23r and the screw advance / retreat mechanism 23m is given from the controller main body 26, and physical quantities such as the speed and position of the screw 22 are detected by a speed sensor, a position sensor, etc. (not shown), and the detection signal is given to the controller main body 26.

[0037] In addition, on the heating cylinder 21, there are a front part of the heating cylinder, a middle part of the heating cylinder, a first rear part of the heating cylinder, and a second rear part of the heating cylinder from the front side to the rear side, and a front heating part 2f, a middle heating part 2m, a first rear heating part 2ra, and a second rear heating part 2rb constituting the heating unit 2 are respectively attached to the outer peripheral surfaces of the respective parts. Similarly, a nozzle heating part 2n is attached to the outer peripheral surface of the injection nozzle 21n. Each of these heating parts, i.e., the heating parts 2f, 2m, 2ra, 2rb, 2n, is constituted by belt heaters 15f, 15m, 15ra, 15rb, 15n and is connected to the heater driver 28, and this heater driver 28 is connected to the controller main body 26. Figure 3 The front view structure diagram of the front heating part 2f is shown. In addition, the heater driver 28 is Figure 9 constituted by the PID control system C shown, which constitutes the main part of the heating control device 1 of the present embodiment described later.

[0038] Thus, a control command for each heating part 2f...2n is given from the controller main body 26 to the heater driver 28, and the heating temperature is detected by a temperature sensor (such as a thermocouple, not shown), and the detection signal is given to the heater driver 28 and the controller main body 26.

[0039] In addition, 3 is a molding machine controller responsible for the overall control of the injection molding machine M, including the above-mentioned controller main body 26 having a computer function with hardware such as a built-in CPU and an internal memory 3m. In the internal memory 3m, there is a data area 3md capable of writing various data types including a database, and a program area 3mp that stores a general control program (software) for performing various arithmetic processes and various control processes (sequence control). Therefore, the molding machine controller 3 includes an HMI control system and a PLC control system, and a PLC program and an HMI program are stored in the internal memory 3m. Through the PLC program, the sequential actions of various processes in the injection molding machine M or the monitoring of the injection molding machine M are executed, and through the HMI program, the setting and display of the operation parameters of the injection molding machine M, the display of the operation monitoring data of the injection molding machine M, etc. are executed.

[0040] In addition, a display 13 is attached to the molding machine controller 3. The display 13 can display necessary information, and in particular, can display the Figure 8 basic setting screen 41 shown. In addition, a touch panel 13t is attached, and various input operations such as input, setting, and selection can be performed using the touch panel 13t. The molding machine controller 3, the heater driver 28, etc. constitute the drive control system Ms in the injection molding machine M.

[0041] Next, with reference to Figures 2 - 9 the heating control device 1 which is the main part of the present invention will be specifically described.

[0042] As a basic function, the heating control device 1 has a function of making the injection molding machine M suitable for the power supply source Po that supplies power to the injection molding machine M.

[0043] Therefore, as a basic structure, it has: a heating unit 2 which is assembled in the injection molding machine M by being selected to be suitable for the electric power amount of the power supply voltage that can be considered in any usage place; and a molding machine controller 3 which includes an actual power supply voltage acquisition function unit Fd, a conversion coefficient calculation function unit Fc, and a supply power control function unit Fp. The actual power supply voltage acquisition function unit Fd directly or indirectly acquires and processes the power supply voltage in the power supply source Po as the actual power supply voltage Vp. The conversion coefficient calculation function unit Fc calculates and processes the elevator gradient rate Rc based on the ratio of the actual power supply voltage Vp to the rated voltage Vs of the heating unit 2 of the injection molding machine M as the conversion coefficient Kc. The supply power control function unit Fp has a power distribution processing unit Fpd, and the power distribution processing unit Fpd controls the supply power Pu to the heating unit 2 by performing power distribution processing of multiplying the conversion coefficient Kc by the control amount Cs of the heating unit 2.

[0044] The heating unit 2 includes a front heating part 2f, a middle heating part 2m, a first rear heating part 2ra, and a second rear heating part 2rb attached to the aforementioned heating cylinder 21, and also includes a nozzle heating part 2n. In this case, as described above, each heating part 2f... uses a strip heater 15f... (refer to Figure 3 ). Thus, as long as at least one strip heater 15n... is included in the heating unit 2, it can be used for the heating control of the heating cylinder which is the most important heating part in the injection molding machine M, so it can also contribute to the stabilization of the operation of the injection molding machine M, and further contribute to the improvement of the molding quality.

[0045] However, in the past, when selecting the belt heater 15f..., a belt heater with a rated voltage Vs corresponding to the power supply Po was selected. For example, when the power supply Po is a three-phase AC power supply of 200 [V], a belt heater with a rated voltage Vs matching this 200 [V] is selected.

[0046] However, in the heating control device 1 of the present embodiment, a belt heater 15f... that can be suitable for the electric power amount of the power supply voltage that can be considered in any usage place is selected.

[0047] Hereinafter, the reasons for this selection and the verification results will be described. The power supply voltages that can be considered in any usage place are mostly "200 [V]", "220 [V]", "380 [V]", "400 [V]", "420 [V]", "440 [V]", "460 [V]", "480 [V]" (refer to Figure 4 ).

[0048] In this case, it is roughly divided into the 200 [V] level and the 400 [V] level. Therefore, on the injection molding machine side, for example, in the case of the belt heater 15f shown in Figure 3 , a pair of belt heaters 15fp and 15fq bent into a semicircular shape are installed in a circular shape on the outer peripheral surface of the heating cylinder 21, and when used as the 400 [V] level, as shown by the dotted line Ls, the terminal 36a and the terminal 36b are connected in series, and a voltage is applied between the terminal 37a and the terminal 37b. In addition, when used as the 200 [V] level, the terminal 36a and the terminal 36b are connected, and the terminal 37a and the terminal 37b are connected, and a voltage is applied between the terminals 36a and 37a connected in parallel. In addition, 35 represents a fixing belt, and 38c represents a fastener.

[0049] Therefore, the belt heater 15f... that can be suitable for the electric power amount of the power supply voltage can be selected as follows. For example, when using a belt heater with a rated voltage Vs of 380 [V] and 1000 [W] and the power supply voltage (Vp) is 440 [V], as will be described in detail later, the current gradient rate Rc is 75 [%] (refer to Figure 4 ), and it can be reduced to the electric power amount equivalent to 1000 [W]. Therefore, in this case, it means that even when the belt heater 15f... with a rated voltage Vs of 380 [V] is selected, the power supply voltage (Vp) can be allowed up to 440 [V]. In addition, in the illustrated case, if used directly at 440 [V] without multiplying by the current gradient rate Rc, it is possible to supply an excessive electric power amount of 1341 [W] and cause the heater to break.

[0050] In addition, the controller main body 26 has an actual power supply voltage acquisition functional unit Fd that directly or indirectly acquires the power supply voltage in the power supply Po and processes it as the actual power supply voltage Vp. Figure 5 The internal circuit of the servo drive 31 ( Figure 2 ) is shown as the actual power supply voltage acquisition functional unit Fd used in the present embodiment. A converter module 32 is provided at the front stage of the servo drive 31, and inverter modules 33a and 33b are provided at the rear stage.

[0051] In this case, the input side of the converter module 32 is connected to the power supply Po, and the output sides of the inverter modules 33a and 33b are connected to the actuators 11a and 11b that use electric motors. The actuators 11a and 11b respectively constitute the aforementioned screw rotation mechanism 23r and screw advance / retreat mechanism 23m. Therefore, the servo drive 31 constitutes a drive circuit 12 that drives the actuators 11a... built in the injection molding machine M.

[0052] In the illustrated case, the power supply voltage (measured value) of the power supply Po is a three-phase AC voltage of 202 [V], and the DC voltage Ed that appears between the output parts 32p and 32n of the converter module 32 is 287 [V]. This DC voltage Ed functions as the actual power supply voltage acquisition functional unit Fd given to the controller main body 26. In this way, the actual power supply voltage acquisition functional unit Fd of the present embodiment has the function of indirectly acquiring and processing the actual power supply voltage Vp from the DC voltage Ed, so it can be implemented without adding an additional voltage detection unit, which can contribute to cost reduction and miniaturization.

[0053] Moreover, the three-phase AC voltage of 202 [V] and the DC voltage Ed (287 [V]) are displayed on the screen of the display 13. Figure 9 The basic setting screen 41 displayed on the display 13 is shown. In the basic setting screen 41, the range surrounded by the imaginary line represents the additional display part 41p added by the heating control device 1 of this time. 42 represents the input AC voltage display part that displays the three-phase AC voltage of 202 [V], and 43 becomes the output DC voltage display part that displays the DC voltage Ed (287 [V]). In addition, 44 is the display part of the rated voltage Vs, and voltage display parts 44f, 44m, 44ra, 44rb, and 44n that display the rated voltage Vs set for the above-mentioned respective heating parts 2f, 2m, 2ra, 2rb, and 2n are shown, and 45 is the display part of the gradient rate corresponding to each voltage Vs, and has gradient rate display parts 45f, 45m, 45ra, 45rb, and 45n corresponding to the respective rated voltages Vs.

[0054] Thus, if a display 13 for displaying at least one of the actual power supply voltage Vp, the rated voltage Vs, and the current rise gradient rate Rc is provided in the molding machine controller 3, an operator can visually confirm the actual power supply voltage Vp, the rated voltage Vs, and the current rise gradient rate Rc obtained indirectly through calculation, and thus can supply an appropriate voltage (electric power) and can easily and reliably determine whether appropriate control has been performed.

[0055] On the other hand, the controller main body 26 has a conversion coefficient calculation function unit Fc that calculates and processes the current rise gradient rate Rc based on the ratio of the actual power supply voltage Vp to the rated voltage Vs of the injection molding machine M into a conversion coefficient Kc.

[0056] Specifically, the actual power supply voltage Vp is calculated from the processed DC voltage Ed using [Equation 100].

[0057]

[0058] In the above case, since the DC voltage Ed is 287 [V], the actual power supply voltage Vp is approximately 202 [V], and the power supply voltage of the power supply Po can be estimated using [Equation 100].

[0059] In addition, the current rise gradient rate Rc can be obtained using [Equation 101]. Now, when the rated voltage Vs is 240 [V] and the actual power supply voltage Vp is 202 [V],

[0060] Rc = (Vs / Vp)^2 × 100 [%] … [Equation 101]

[0061] The current rise gradient rate Rc is 70.8 [%]. Thus, the current rise gradient rate Rc can be calculated and processed based on the actual power supply voltage Vp and the rated voltage Vs. Figure 4 The current rise gradient rate Rc obtained by calculating and processing the power supply voltages of the various power supplies Po described above is shown in a list.

[0062] In addition, in Figure 8 the rated voltage Vs display unit 44, the rated voltage Vs set for each of the heating units 2f, 2m, 2ra, 2rb, and 2n is shown. Thus, the amount of electric power corresponding to the rated voltage Vs used in the injection molding machine M in correspondence with the power supply voltage can be set using the current rise gradient rate Rc, and in the gradient rate display unit 45, the calculated current rise gradient rate Rc is displayed in correspondence with each rated voltage Vs.

[0063] On the other hand, the obtained elevator gradient rate Rc is supplied to the power supply control function unit Fp in the controller main body 26 as a conversion coefficient Kc. By multiplying the control amount Cs of the heating unit 2, the power supply Pu to the heating unit 2 can be controlled.

[0064] Figure 9 It is the main circuit of the heater driver 28. An example of the PID control system C that serves as the power supply control function unit Fp for the belt heater 15f is shown, which has a PID circuit 52 and a power distributor 53. The PID circuit 52 includes: a subtraction unit 54 that subtracts the detected temperature PV [°C] from the set temperature (command value) SV [°C] given by the controller main body 26; an integral operation unit 56 that calculates the integral operation amount based on the deviation e obtained from the subtraction unit 54; a proportional operation unit 55 that calculates the proportional operation amount based on the deviation e; a differential operation unit 57 that calculates the differential operation amount based on the deviation e; an addition unit 58 that adds the output operation amounts of the integral operation unit 56, the proportional operation unit 55, and the differential operation unit 57; and an output limiter 14 that limits the output operation amount MVt of the addition unit 58 between the upper limit value and the lower limit value. The output operation amount MV of the output limiter 14 is given to the power distributor 53. In addition, this PID control system C is a generally well-known PID control system.

[0065] In this case, the output limiter 14 can have a function of limiting the conversion coefficient Kc to not exceed 100%. If such an output limiter 14 is provided, it is particularly possible to avoid the generation of excessive power, so that it is possible to avoid heater disconnection and the like, realize the protection of the injection molding machine M, and also contribute to the further improvement of safety and reliability.

[0066] Moreover, the above-mentioned conversion coefficient Kc is provided to the power distributor 53 that functions as a power distribution processing unit Fpd, and the power distribution processing is performed by the power distributor 53. That is, in the power distributor 53, the power supply Pu to the belt heater 15f is controlled by the power distribution process of multiplying the conversion coefficient Kc by the control amount Cs (MV) of the belt heater 15f (heating unit 2).

[0067] The power distribution process is performed by waveform thinning processing that thins out a part of the AC waveform W based on the conversion coefficient Kc. Thus, if the power distribution process is performed by waveform thinning processing that thins out a part of the AC waveform W based on the conversion coefficient Kc, the AC waveform W can be changed (distributed) by time-sharing processing. Therefore, without accompanying complication and enlargement of the control system, it can be easily implemented. In addition, if the output manipulated variable MV in the PID control system C with a specified PID constant set is used as the control quantity Cs, the PID control system C for the temperature during molding is used, so stable and reliable control can be performed.

[0068] Figure 6 and Figure 7 The waveform of the AC waveform W distributed by the power supply control function unit Fp having the power distributor 53 is shown. The waveform indicated by the dotted line including the solid line is the case where the output distribution is 100 [%]. In the illustrated case, 220 [V] AC power of 50 or 60 [Hz] can be directly output.

[0069] Figure 6 In the waveform thinning process where the control quantity Cs is multiplied by the elevator gradient rate Rc (N%), the supplied power Pu has an interval of N% where the half-wave Wh shown by the solid line exists and an interval where the half-wave Wo shown by the dotted line is thinned out at a ratio of (100 - N)%. In addition, Figure 7 In the waveform thinning process where the control quantity Cs is multiplied by the elevator gradient rate Rc (Q%), the supplied power Pu indicates that power is supplied in the Wf interval of Q% shown by the solid line and power supply is stopped, that is, thinned out, in the Wo interval of (100 - Q)% shown by the dotted line. The control cycle is approximately about 0.5 seconds. In addition, the start point and the end point in any thinning case are arbitrary, but from the viewpoint of suppressing generation of unnecessary noise and the like, it is preferably performed in the interval from the start point 0 [V] point to the end point 0 [V] point.

[0070] Next, with reference to each figure, the processing sequence of the heating control method of the present embodiment will be described according to Figure 1 the flowchart shown.

[0071] First, at the manufacturer side, that is, in the manufacturing stage of the injection molding machine M, a belt heater 15f... of the heating unit 2 that can be suitable for the electric power amount of the power supply voltage that can be considered in any use place is selected (step S1). Then, the selected belt heater 15f... is installed on the outer peripheral surface of the heating cylinder 21 as Figure 3 shown, and thus the injection molding machine M as a whole is manufactured (step S2). On the other hand, after the injection molding machine M is completed, the rated voltage 220 [V]... corresponding to each belt heater 15f... is set (step S3). Figure 8Shown as an example is the rated voltage of 220 [V] set for each part of the heating cylinder 21 in the additional display section 41p of the basic setting screen 41...

[0072] In this case, the setting of the rated voltage of 220 [V]... can be carried out at this moment, or can be carried out after being moved into any of the following setting areas. Additionally, at this moment, since the specific usage location has not been determined, the completed injection molding machine M can be stored in a prescribed storage warehouse, etc. (step S4).

[0073] On the other hand, now assume a case where an order for setting the injection molding machine M is received from a user in any region. In this case, a prescribed model ordered by the user from the stored injection molding machines M is moved into the user's region and set in a molding factory, etc. (step S11). After the setting of the injection molding machine M is completed, the injection molding machine M is connected to the power supply Po and the power is turned on (step S12).

[0074] Thereby, the actual power supply voltage Vp, which is the DC voltage Ed between the output parts 32p and 32n of the converter module 31, is taken in by the actual power supply voltage acquisition functional part Fd of the controller main body 26 of the heating control device 1 (step S13). Additionally, the conversion coefficient operation functional part Fc of the controller main body 26 calculates the conduction gradient rate Rc based on the ratio of the actual power supply voltage Vp to the rated voltage Vs in the injection molding machine M (step S14). Then, the obtained conduction gradient rate Rc is given as the conversion coefficient Kc to Figure 9 the power distribution processing part Fpd shown, that is, the power distributor 53 (step S15). And the conversion coefficient Kc is Figure 8 displayed in the additional display section 41p shown (step S16).

[0075] On the other hand, in the power distributor 53, the following power distribution processing is carried out: the power is distributed by multiplying the control amount Cs (output operation amount MV) of the heating unit 2 by the conversion coefficient Kc (step S17). Thereby, the supply power (Vout) to the belt heater 15f, that is, the supply power after a part of the AC waveform is removed, is output. Although the processing process for the belt heater 15f has been described, the same processing is also carried out for the other belt heaters 15m, 15ra, 15rb, 15n.

[0076] Then, after the processing for all the rated voltages Vs is completed, the setting processing for the power supply voltage is completed (steps S18, S19). That is, the basic setting of the power supply voltage in the power supply Po for supplying power to this injection molding machine M to make this injection molding machine M suitable is completed.

[0077] Thus, during operation, the supplied power processed by the power distribution processing unit Fpd, i.e., the supplied power with a part of the AC waveform removed, is output and processed to the corresponding belt heaters 15f… (step S20).

[0078] Therefore, according to the heating control method and the heating control device 1 of the injection molding machine of this embodiment, as a basic method, a heating unit 2 that can be suitable for the amount of power of the power supply voltage that can be conceived in any usage place is pre-selected and assembled in the injection molding machine M. When the injection molding machine M is set up at this usage place, the power supply voltage in the power supply Po is directly or indirectly obtained and processed as the actual power supply voltage Vp by the molding machine controller 3 provided in the injection molding machine M. And the conduction rate Rc based on the ratio of the actual power supply voltage Vp to the rated voltage Vs of the heating unit 2 provided in the injection molding machine M is calculated and processed as the conversion coefficient Kc. By multiplying the conversion coefficient Kc by the power distribution processing of the control amount Cs of the heating unit 2, the supplied power Pu to the heating unit 2 is controlled. Therefore, as an advantage of the power distribution processing, it is possible to achieve the facilitation of control and implementation without using a large-scale voltage conversion unit or current conversion unit, and further, it is possible to achieve the miniaturization of the device. And especially when the injection molding machine M is moved to (set up at) an area with various power supply voltages, even in a state where the power supply Po, the power supply voltage, and the rated voltage Vs of the heating unit 2 provided in the injection molding machine M are not suitable, the injection molding machine M etc. can be directly set up without replacing the heating unit 2 such as the belt heater, and it is possible to avoid the problems of wasting useless setup time and generating useless costs. And as long as one heating unit with an appropriate power capacity is selected, it is also possible to enjoy the secondary effect that the injection molding machine etc. manufactured in advance can be stored, and the degrees of freedom in design and production can be improved.

[0079] As described above, the preferred embodiments have been described in detail, but the present invention is not limited to such embodiments. In terms of the detailed structure, shape, material, quantity, numerical value, method, etc., within the scope not departing from the gist of the present invention, it can be arbitrarily changed, added, or deleted.

[0080] For example, the embodiment shows a case where the power supply voltage in the power supply Po is obtained as the actual power supply voltage Vp and indirectly obtained from the DC voltage Ed in the drive circuit 12, but it may also be directly detected. Further, as the power distribution process, a case where the waveform thinning process of thinning out a part of the AC waveform W is performed based on the conversion coefficient Kc is shown, but the case of using other known methods of changing the power amount such as changing the period of the waveform like PWM control is not excluded. In addition, the control amount Cs is preferably applied to the output operation amount MV in the PID control system in which a prescribed PID constant is set, but the case of applying it to the control amount of other different control systems is not excluded. On the other hand, a case where at least one of the actual power supply voltage Vp, the rated voltage Vs, and the elevator gradient rate Rc is displayed on the display 13 is illustrated, but it is not an essential component. Further, the output limiter 14 that limits the conversion coefficient Kc to not more than 100% does not exclude the case of performing the limitation by other methods, and the heating unit 2 can apply various heating methods represented by the belt heater 15n….

[0081] The heating control method and the heating control device 1 of the present invention can be used when connecting an injection molding machine to a power supply in each region having a different power supply voltage to adapt the injection molding machine.

Claims

1. A heating control method for an injection molding machine, which makes the injection molding machine suitable for a power supply for powering the injection molding machine, characterized in that: A heating unit that is compatible with the amount of power of the power supply voltage that can be expected in any place of use is pre-selected and assembled in the injection molding machine. When the injection molding machine is set in the place of use, the power supply voltage in the power supply source is directly or indirectly obtained and processed as an actual power supply voltage through a molding machine controller of the injection molding machine, and the conduction gradient rate based on the ratio of the actual power supply voltage to the rated voltage of the heating unit of the injection molding machine is calculated and processed as a conversion coefficient. The power supply to the heating unit is controlled by multiplying the conversion coefficient by the power distribution processing of the control amount of the heating unit.

2. The heating control method of the injection molding machine according to claim 1, characterized in that: The actual power supply voltage is indirectly obtained from a DC voltage in a drive circuit that drives an actuator built into the injection molding machine.

3. The heating control method of the injection molding machine according to claim 1, characterized in that: The power distribution process is performed by waveform thinning-out processing of thinning out a portion of the AC waveform based on the conversion factor.

4. The heating control method of the injection molding machine according to claim 3, characterized in that: The waveform thinning process is performed by multiplying the control amount by the power gradient rate.

5. The heating control method of the injection molding machine according to claim 1, characterized in that: The control amount is a control amount in a PID control system in which predetermined PID constants are set.

6. The heating control method of the injection molding machine according to claim 1, characterized in that: At least one band heater is included in the heating unit.

7. A heating control device for an injection molding machine, which makes the injection molding machine suitable for a power supply source for powering the injection molding machine, characterized in that: The heating control device of the injection molding machine has: A heating unit that is assembled in an injection molding machine by being selected to be compatible with an amount of electric power that allows a power supply voltage that can be expected in any place of use; as well as A molding machine controller includes an actual power supply voltage acquisition function unit, a conversion coefficient calculation function unit, and a supply power control function unit. The actual power supply voltage acquisition function unit directly or indirectly acquires the power supply voltage in the power supply source and processes it into an actual power supply voltage. The conversion coefficient calculation function unit calculates the conduction gradient rate based on the ratio of the actual power supply voltage to the rated voltage of the heating unit possessed by the injection molding machine as a conversion coefficient. The supply power control function unit has a power distribution processing function for controlling the supply power to the heating unit by multiplying the conversion coefficient by the power distribution processing of the control amount of the heating unit.

8. The heating control device for an injection molding machine according to claim 7, characterized in that: The actual power supply voltage is indirectly obtained from a DC voltage in a drive circuit that drives an actuator built into the injection molding machine.

9. The heating control device for an injection molding machine according to claim 7, characterized in that: The heating unit includes at least one band heater.

10. The heating control device for an injection molding machine according to claim 7, characterized in that: The molding machine controller includes a display for displaying at least one of the actual power supply voltage, the rated voltage, and the power-on gradient rate on a screen.

11. The heating control device for an injection molding machine according to claim 7, characterized in that: The molding machine controller has an output limiter that limits the conversion factor to not more than 100%.

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