Control of an injection molding machine

Abstract

Control of an injection molding machine (M), wherein the injection molding machine (M) is equipped with an injection molded part (1), the control unit controls the injection molding machine (M) to dose and plasticize a resin up to a dosing end position (X) m ) in a dosing process, to move the injection part (1) forward while maintaining an injection speed at an injection speed switching position (X) v ) is switched in an injection process, and to proceed to a holding pressure process when a predetermined injection holding pressure switchover condition is met, the control system includes the following: a part-injection position setting unit that defines a process value in relation to a process position of the part (1) and sets the process position of the part according to the defined process value; and a correction value setting unit that sets a correction value (Δs) to correct the process position of the injection-molded part (1), and wherein the injection part position setting unit determines the dosing end position (X) by means of the correction value (Δs). m ) and the spray speed switching position (X v ) as the process position of the injection molded part (1) in each predetermined cycle.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention

[0001] The present invention relates to a controller of an injection molding machine that controls a process position of a molded part in the injection molding machine in every predetermined cycle. 2. Description of related technology

[0002] AT 404 076 B discloses a control of an injection molding machine in which a correction value is subtracted only from the switching point of the screw in order to obtain a corrected switching point.

[0003] WO 91 / 14562 A1 discloses a method for correcting certain errors in the injection molding process.

[0004] As in Fig. As shown in Figure 1, an injection molding machine M has a mold clamping section Mc and an injection section Mi on a machine base 2. The mold clamping section Mc opens and closes a mold 40 (a movable-side mold 40a and a fixed-side mold 40b). The injection section Mi heats and melts a resin material (pellet) and injects the molten resin into a cavity of the mold 40.

[0005] First, the mold clamping section Mc will be described. The mold clamping section Mc consists of a movable platen 30, a back platen 31, a switch 32, a fixed platen 33, a crosshead 34, a mold clamping servomotor M3 configured to move the movable platen 30 forward and backward, a servomotor M4 configured to push an ejection pin for ejecting a molded object from the mold, and a ball screw shaft 38 driven by the mold clamping servomotor M3. The fixed platen 33 is fixed to a machine base. The fixed platen 33 and the back platen 31 are connected by a plurality of connecting rails 41. The movable platen 30 is positioned to move (forward and backward) along the connecting rails 41 between the fixed platen 33 and the back platen 31 by operation of the switch 32.

[0006] The mold 40a on the movable side is fixed to the movable platen 30, and the mold 40b on the fixed side is fixed to the fixed platen 33. The mold 40 is configured by the mold 40a on the movable side and the mold 40b on the fixed side. The ball screw shaft 38 is driven by the clamping servo motor M3, and the crosshead 34 attached to the ball screw shaft 38 moves forward and backward, thereby changing the position of the movable platen 30. In this case, the movable platen 30 moves when the crosshead 34 moves forward (in a right direction in Fig. 1), is moved forward by the switch 32, and thus the mold is closed. Subsequently, a mold clamping force is generated by multiplying a driving force of the clamping servo motor M3 by a switching magnification, and the mold is closed by the generated mold clamping force.

[0007] Next, the injection area Mi will be described. A nozzle 12 is mounted at the leading end of an injection cylinder portion 10, and a screw 1 is inserted into a cylinder 5 of the injection cylinder portion 10. The screw 1 is rotated by a servomotor M2 for rotating the screw and moved in the axial direction of the screw 1 by a servomotor M1 for moving the screw back and forth. Furthermore, reference numeral 14 denotes a hopper that supplies resin to the cylinder 5. Fig. 1 illustrates a state in which the injection nozzle 12 at the leading end of the injection cylinder portion 10 is in close contact with a resin injection port of the fixed platen 33 in the injection area Mi. In this state, a resin melted by the rotation of the screw 1 is injected into the mold 40 (the movable-side mold 40a and the fixed-side mold 40b) by a forward movement of the screw 1.

[0008] A molding operation by means of the injection molding machine M is described. When the mold clamping servo motor M3 rotates in a normal direction, the ball screw shaft 38 rotates in the normal direction, and the crosshead 34 engaged with the ball screw shaft 38 by the screw moves forward (in the right direction in Fig. 1). The changeover switch 32 is then actuated, and the movable plate 30 moves forward.

[0009] When the mold 40a on the movable side, attached to the movable platen 30, comes into contact with the mold 40b attached to the fixed platen 33 (a state in which the mold is closed), a mold closing operation begins. During the mold closing operation, when the mold closing servomotor M3 is further driven in the normal direction, the mold closing force is generated in the mold 40. Then, when the screw reversing servomotor M1 provided in the injection area Mi is driven and the screw 1 advances in the axial direction, the molten resin is poured into a cavity formed in the mold 40 (the movable-side mold 40a and the fixed-side mold 40b).

[0010] When performing the mold opening operation, the mold closing servomotor M3 is driven in a reverse direction to rotate the ball screw shaft 38 in the reverse direction. Accordingly, the crosshead 34 moves backward, and the movable platen 30 moves (backward) in a direction of approaching the back platen 31. When the mold opening operation is completed, the servomotor M4 is actuated to push out the ejector pin (not shown) for ejecting a molded object from the movable-side mold 40a. Consequently, the ejector pin is pushed out from an inner surface of the movable-side mold 40a, and the molded object in the movable-side mold 40a is pushed out of the movable-side mold 40a.

[0011] In the injection cylinder part 10, the screw 1 is rotated by the screw-rotating servo motor M2 to melt the resin, and the molten resin is thus fed forward. Subsequently, the screw 1 moves backward by being rotated with this resin pressure by the screw-reverse and forward movement servo motor M1 to perform metering. After that, the screw 1 moves forward by the screw-reverse and forward movement servo motor M1 to inject the molten resin into the mold 40. To prevent backflow of the resin during injection, a check valve 3 is provided at the leading end of the screw 1.

[0012] The injection cylinder part 10 in the injection molding machine M is described with reference to Fig. 2 described.

[0013] The screw 1 is inserted into the cylinder 5, and a screw head 2, the check valve 3, and a check valve seat 4 are provided at the leading end of the screw 1. The check valve 3 is positioned to be movable in the axial direction of the screw 1 to a reduced diameter part between body parts of the screw 1. The check valve seat 4 is formed in the reduced diameter part of the leading end of the screw 1 and provided on the side of the body of the screw to come into close contact with the check valve 3 and close a resin channel.

[0014] In a metering process, the screw 1 rotates, and the resin pellet supplied from the rear of the screw 1 is melted by shear heat generated by the rotation of the screw 1 and heat from a heater (not shown) provided on an outer side of the cylinder 5 into which the screw 1 is inserted. The molten resin increases the resin pressure at a rear of the check valve 3 to generate a force for pushing the check valve 3 forward. As the check valve 3 is pushed forward, the resin of a rear screw compression part 6 is supplied to the front of the check valve 3 through a gap between the check valve 3 and the reduced diameter part of the leading end of the screw to increase a pressure in the cylinder 5 in front of the screw head 2.

[0015] When the resin pressure at the front of the check valve 3 exceeds a predetermined pressure, the screw 1 is pushed backward, thus reducing the pressure at the front of the check valve 3. Since the pressure at the rear of the check valve 3 is higher than the pressure at the front of the check valve 3, as the screw 1 continues to rotate, the continuously molten resin is supplied to the front of the check valve 3. When the screw 1 moves backward to a predetermined range, the rotation of the screw stops, and the dispensing process is completed.

[0016] Next, an injection process is started. As the screw 1 advances to fill the resin into the mold 40, the pressure of the resin accumulated in the front end of the screw head 2 increases. Consequently, the check valve 3 moves backward and comes into close contact with the check valve seat 4 to close the resin channel, thus preventing the molten resin from flowing backward along the screw 1.

[0017] The resin backflow proceeds from the front of the check valve 3 to the rear until the resin channel is closed by the check valve 3 after injection is started. Backflow occurs in the resin channel, but can also occur in a gap formed by a difference between an outer diameter of the check valve 3 and an inner diameter of the cylinder 5. When the injection molding machine is continuously used for a long period of time, the check valve 3 and the cylinder 5 become worn, and the amount of backflow fluctuates. Since the amount of backflow affects the amount of resin filled into the mold, the quality of the molded article is affected by the amount of backflow.

[0018] Furthermore, impurities such as color additives or resin burns sometimes accumulate on the inside of the cylinder 5 in the compression part 6 of the screw. The presence of these impurities also affects the quality of the molded article. To remove the impurities from the inside of the cylinder 5, it is necessary to rinse the injection cylinder part 10 with a detergent or disassemble and clean it, which requires cost and labor.

[0019] JP 2008302527 A discloses the facts that with continuous use of an injection molding machine, a check valve and the inner wall of a cylinder wear, the backflow occurring from the front of the check valve to the back increases, and the backflow of resin affects the amount of resin filled into a mold and the quality of a molded article. Furthermore, the above-mentioned patent document discloses, as a measure of such an effect, a technique that detects a screw torque due to backflow of resin occurring from the front of the check valve to the back, and estimates the wear state of the check valve by a change in physical quantities such as a magnitude of a peak of the screw torque, a time of occurrence of a peak, a position of the screw at that time, and the like.

[0020] According to the technique disclosed in the above-mentioned patent document, by detecting the screw rotation force due to the backflow of resin, it is possible to calculate a progress of the wear state of the check valve or the like up to the current date and predict a future progress of the wear from the estimation result, but the above-mentioned patent document does not specifically disclose the method for reducing the wear amount. SUMMARY OF THE INVENTION

[0021] An object of the invention is to provide a controller of an injection molding machine provided with a molded part, which can reduce the frequency of performing maintenance by flushing or disassembling and cleaning the injection molding machine, to improve productivity and extend the service life of a cylinder that has been replaced due to local wear.

[0022] According to the present invention, in an injection section of the injection molding machine, a position in the cylinder that is easily worn is periodically changed by periodically correcting a metering completion position or an injection speed switching position. This makes it possible to reduce the frequency of performing maintenance such as flushing or disassembling and cleaning the injection molding machine, thereby improving productivity and extending the life of the cylinder. Furthermore, in the related art, impurities are deposited at a specific location in the cylinder. However, in the present invention, a position approached by a compression part of the screw in the cylinder can be changed by periodically correcting the metering completion position to expand the position of the cylinder relative to the compression part of the screw, making it possible to extend the period until impurities are deposited.

[0023] In the injection molding machine controller according to the invention, the injection molding machine is provided with the molded part, and the controller controls the injection molding machine to perform metering and plasticizing of a resin up to a metering completion position in a metering process, to advance the molded part while switching an injection speed at an injection speed switching position in an injection process, and to proceed to a holding pressure process when a predetermined injection holding pressure switching condition is met. The controller includes a molded part position setting unit that sets a process value related to a process position of the molded part and adjusts the process position of the molded part according to the set process value, and a correction value setting unit that sets a correction value for correcting the process position of the molded part.Then, the molded part position setting unit sets the metering completion position and the injection speed switching position as the process position of the molded part in each predetermined cycle using the correction value.

[0024] The process position of the molded part is a control target value that comprehensively indicates the metering completion position, the injection speed switching position, and the injection holding pressure switching position. The process value is a parameter for determining the actual process position.

[0025] According to the control of the injection molding machine of the invention, since the process position of the molded part such as the metering completion position or the injection speed switching position can be changed every predetermined cycle, the position in the cylinder which is easily worn is periodically changed, so that the frequency of performing maintenance by flushing or disassembling and cleaning the injection molding machine can be reduced to improve productivity and extend the life of the cylinder.

[0026] The injection holding pressure switching condition may be determined based on the position of the molded part, and the molded part position setting unit may further set an injection holding pressure switching position as the process position of the molded part by means of the correction value.

[0027] According to the above embodiment, when the injection holding pressure switching condition is determined by the position of the molded part, the injection holding pressure switching position is further adjusted using the correction value in addition to the metering completion position and the injection speed switching position. Therefore, even if the metering completion position is changed, the injection holding pressure switching position is also changed at the corresponding position, so there is no possibility of changing the amount of resin injected into the mold.

[0028] The molded part position adjustment unit can read the correction value every predetermined cycle and determine a new process value by adding or subtracting the read correction value to or from the process value to adjust the process position of the molded part based on the new process value.

[0029] According to the above embodiment, the process value is set as a numerical value indicating the process position of the molded part, the process value is replaced with the new process value by adding or subtracting the correction value to or from the process value in every predetermined cycle, and the new process position of the molded part is set based on the new process value.

[0030] The correction value setting unit can set a correction value corresponding to the number of cycles to adjust the process position of the molded part based on a result obtained by adding or subtracting the read correction value to or from the process value.

[0031] The predetermined number of cycles may be the number of cycles previously stored in a storage device or the number of cycles input by an input unit.

[0032] According to the invention, it is possible to provide the control system of the injection molding machine with the molded part, which can reduce the frequency of performing maintenance by flushing or disassembling and cleaning the injection molding machine, so as to improve productivity and prolong the service life of the cylinder that has been replaced due to local wear.

[0033] In the invention, the injection molding part of the injection molding machine can be either a screw or a piston. SHORT DESCRIPTION OF THE DRAWING

[0034] The above and other objects and features of the present invention will become apparent from the following description of embodiments with reference to the accompanying drawings, in which: Fig. 1 is a diagram showing an overall configuration of an injection molding machine; Fig. 2 an enlarged diagram of an injection cylinder part of the Fig. 1 shown injection moulding machine; Fig. 3A to 3C are diagrams each showing an injection process in the injection cylinder part of the Fig. 1 represent the injection moulding machine shown; Fig. 4 is a flowchart illustrating a first example of correction processing of screw process values ​​executed by a controller of the injection molding machine according to the present invention; Fig. 5 is a flowchart illustrating a second example of the correction processing of the screw process values ​​executed by the controller of the injection molding machine according to the present invention; Fig. 6 is a flowchart illustrating a third example of the correction processing of the screw process values ​​executed by the controller of the injection molding machine according to the invention; and Fig. 7 is a flowchart illustrating a fourth example of the correction processing of the screw process values ​​executed by the controller of the injection molding machine according to the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0035] In the invention, a process position of a screw, e.g., a metering completion position or a speed switching position, is adjusted in every predetermined cycle in an injection cylinder part of an injection molding machine.

[0036] An embodiment of the invention will be described below with reference to the drawing.

[0037] As an injection molding machine to be controlled by the controller according to the invention and as an injection cylinder part provided in the injection molding machine, an injection molding machine and an injection cylinder part similar to the prior art as shown in Fig. 1 and Fig. 2 shown, used.

[0038] Fig. 3A to 3C are diagrams each illustrating an injection process in an injection cylinder part 10. Fig. 3A illustrates a metering completion position, and a certain amount of resin is metered between the metering completion position and a leading end of a cylinder 5. After metering is completed, an injection process is performed, and the screw 1 advances in the cylinder 5. Fig. 3B is a diagram illustrating a spray speed switching position for changing a forward speed of the screw 1 at the position in the course of a forward movement of the screw 1. Fig. 3C is a diagram showing a shot holding pressure switching position for switching to a shot holding pressure status when the forward movement of the screw 1 is completed.

[0039] Here, a screw process value is assumed that increases as the screw 1 moves backward, and the value indicating a position of a leading end of the screw 1 is zero. Regarding these screw process values, a screw process value (dispensing completion value) indicating the dispensing completion position is set to Xm, and a screw process value (injection speed switching value) indicating the injection speed switching position is set to Xv. This dispensing completion value Xm and the injection speed switching value Xv are stored in a memory device.

[0040] In addition, a lower limit value Xmin of the metering completion value Xm is usually set as the amount of movement of the screw from the metering completion position to the leading position of the screw in the injection / holding process. An upper limit value Xmax of the metering completion value Xm can be input as a molding condition, a value previously stored in the memory device, or a movable upper limit value of the injection molding machine.

[0041] First, a first example of the correction processing of the screw process value will be explained with reference to a flowchart of Fig. 4. In this example, the screw process values ​​as a correction target are the dosing completion value Xm and the injection speed switching value Xv.

[0042] In step SA1, an initial value of the dosage completion value Xm indicating a dosage completion position and an initial value of the injection speed switching value Xv indicating the injection speed switching position are set.

[0043] In step SA2, a lower limit value Xmin and an upper limit value Xmax of the dosing completion value Xm are set.

[0044] In step SA3, the predetermined number of cycles is set.

[0045] In step SA4, the metering completion position is set to a position of the screw process value Xm and the injection speed switching position is set to a position of the screw process value Xv, and then the injection process is executed. When predetermined injection hold pressure switching conditions are met, such as an internal pressure value or a time elapsed from the start of the injection process, a hold pressure process is executed. Furthermore, the number of injections is incremented by one.

[0046] In step SA5, it is determined whether the number of injections reaches the predetermined number of cycles set in step SA3. If the number of injections reaches the predetermined number of cycles (YES), the processing proceeds to step SA6, and if the number of injections does not reach the predetermined number of cycles (NO), the processing returns to step SA4.

[0047] In step SA6, the number of injections is reset to zero.

[0048] In step SA7, a correction value Δs is read out.

[0049] In step SA8, it is determined whether or not the relationship Xm + Δs ​​≥ Xmax or Xm + Δs ​​≤ Xmin is satisfied; that is, it is determined whether or not a position of the screw corresponding to a dosage completion value Xm obtained by the aforementioned addition falls within a predetermined range when the correction value Δs is added to the dosage completion value Xm. If the position of the screw is within the predetermined range (YES), the processing proceeds to step SA9, and if the position of the screw is not within the predetermined range (NO), the processing proceeds to step SA10.

[0050] In step SA9, a sign of the correction value Δs is reversed.

[0051] In step SA10, the correction value Δs is added to the screw metering completion value Xm and the injection speed switching value Xv, respectively, to newly determine a screw metering completion value Xm and an injection speed switching value Xv, respectively.

[0052] In step SA11, it is determined whether the injection process is completed. If the injection process is completed (YES), the processing is terminated; if the injection process is not completed (NO), the processing returns to step SA4.

[0053] Next, a second example of the correction processing of the screw process value will be explained with reference to a flowchart of Fig. 5. In this example, the screw process values ​​as a correction target are the dosing completion value Xm, the injection speed switching value Xv, and the injection holding pressure switching value Xp.

[0054] In step SB1, an initial value of the metering completion value Xm indicating the metering completion position, an initial value of the injection speed switching value Xv indicating the injection speed switching position, and an initial value of the injection holding pressure switching value Xp indicating the injection holding pressure switching position are set.

[0055] In step SB2, a lower limit value Xmin and an upper limit value Xmax of the dosing completion value Xm are set.

[0056] In step SB3, the predetermined number of cycles is set.

[0057] In step SB4, the metering completion position is set to a position of the screw process value Xm and the injection speed switching position is set to a position of the screw process value Xv, and then the injection process is executed. Furthermore, the injection holding pressure switching position is set to a position of the screw process value Xp, and when the screw is moved to the position of the screw process value Xp, the holding pressure process is executed. Furthermore, the number of injections is incremented by one.

[0058] In step SB5, it is determined whether or not the number of injections reaches the predetermined number of cycles set in step SB3. If the number of injections reaches the predetermined number of cycles (YES), the processing proceeds to step SB6, and if the number of injections does not reach the predetermined number of cycles (NO), the processing returns to step SB4.

[0059] In step SB6, the number of injections is reset to zero.

[0060] In step SB7 a correction value Δs is read out.

[0061] In step SB8, it is determined whether or not the relationship Xm + Δs ​​≥ Xmax or Xm + Δs ​​≤ Xmin is satisfied; that is, it is determined whether or not a position of the screw corresponding to a dosage completion value Xm obtained by the aforementioned addition falls within a predetermined range when the correction value Δs is added to the dosage completion value Xm. If the position of the screw is within the predetermined range (YES), the processing proceeds to step SB9, and if the position of the screw is not within the predetermined range (NO), the processing proceeds to step SB10.

[0062] In step SB9, a sign of the correction value Δs is reversed.

[0063] In step SB10, the correction value Δs is added to the metering completion value Xm, the injection speed switching value Xv, and the injection holding pressure switching value Xp, respectively, to newly determine a screw metering completion value Xm, an injection speed switching value Xv, and an injection holding pressure switching value Xp, respectively.

[0064] In step SB11, it is determined whether the injection process is completed. If the injection process is completed (YES), the processing is terminated; if the injection process is not completed (NO), the processing returns to step SB4.

[0065] Next, a third example of the correction processing of the screw process value will be explained with reference to a flowchart of Fig. 6. In this example, the screw process values ​​as a correction target are a metering completion reference value Xm' and an injection speed switching reference value Xv'; a correction value Δs corresponding to the number of cycles is read out without changing this metering completion reference value Xm' and this injection speed switching reference value Xv', and the correction value Δs is added to the metering completion reference value Xm' and the injection speed switching reference value Xv', respectively. Using the values ​​obtained by the aforementioned addition, a screw metering completion position and an injection speed switching position are set.

[0066] In step SC1, a screw metering completion reference value Xm' indicating a reference position of screw metering completion and the injection speed switching reference value Xv' indicating a reference position of injection speed switching are set.

[0067] In step SC2, a table of a relationship between the number of cycles and the correction value Δs is read out.

[0068] In step SC3, the metering completion position is set to a position of the screw process value (Xm' + Δs), and the injection speed switching position is set to a position of the screw process value (Xv' + Δs), and then the injection process is executed. When predetermined injection hold pressure switching conditions are met, such as an internal pressure value or a time elapsed from the start of the injection process, a hold pressure process is executed. Furthermore, the number of injections is incremented by one.

[0069] In step SC4, it is determined whether the number of injections reaches the predetermined number of cycles defined in the table from step SC2. If the number of injections reaches the predetermined number of cycles (YES), processing proceeds to step SC5, and if the number of injections does not reach the predetermined number of cycles (NO), processing returns to step SC3.

[0070] In step SC5, the correction value Δs corresponding to the number of cycles is reread based on the table.

[0071] In step SC6, it is determined whether the injection process is completed. If the injection process is completed (YES), processing ends; if the injection process is not completed (NO), processing returns to step SC3.

[0072] Next, a fourth example of the correction processing of the screw process value will be explained with reference to a flowchart of Fig.7. In this example, the screw process values ​​as a correction target are a metering completion reference value Xm', an injection speed switching reference value Xv', and an injection holding pressure switching reference value Xp'; a correction value Δs corresponding to the number of cycles is read out without changing this metering completion reference value Xm', this injection speed switching reference value Xv', and this injection holding pressure switching reference value Xp', and the correction value Δs is added to the metering completion reference value Xm', the injection speed switching reference value Xv', and the injection holding pressure switching reference value Xp', respectively. Using the values ​​obtained by the aforementioned addition, a screw metering completion position, an injection speed switching position, and an injection holding pressure switching position are set.

[0073] In step SD1, a screw metering completion reference value Xm' indicating a reference position of screw metering completion, the injection speed switching reference value Xv' indicating a reference position of injection speed switching, and the injection holding pressure switching reference value Xp' indicating a reference position of injection holding pressure switching are set.

[0074] In step SD2, a table of a relationship between the number of cycles and the correction value Δs is read out.

[0075] In step SD3, the metering completion position is set to a position of the screw process value (Xm' + Δs), and the injection speed switching position is set to a position of the screw process value (Xv' + Δs), and then the injection process is executed. Furthermore, when the injection holding pressure switching position is set to a position of the screw process value (Xp' + Δs), and the screw is moved to the position of the screw process value (Xp' + Δs), the holding pressure process is executed. Furthermore, the number of injections is increased by one.

[0076] In step SD4, it is determined whether or not the number of injections reaches the predetermined number of cycles defined in the table from step SD2. If the number of injections reaches the predetermined number of cycles (YES), processing proceeds to step SD5, and if the number of injections does not reach the predetermined number of cycles (NO), processing returns to step SD3.

[0077] In step SD5, the correction value Δs corresponding to the number of cycles is re-read based on the table.

[0078] In step SD6, it is determined whether the injection process is completed. If the injection process is completed (YES), processing ends; if the injection process is not completed (NO), processing returns to step SD3.

[0079] It should be noted that the correction value Δs in the first and second examples of screw process value correction processing is a constant number, but it does not have to be a constant number. For example, the correction value can be determined based on the formula stored in a storage device and can be determined by a random number.

Claims

[1] Control of an injection molding machine (M), wherein the injection molding machine (M) is provided with an injection-molded part (1), the control system controls the injection molding machine (M) to complete the dosing and plasticization of a resin up to a dosing completion position (X m ) in a dosing process, to move the injection-molded part (1) forward while maintaining an injection speed at an injection speed switching position (X v ) in an injection process, and to proceed to a holding pressure process when a predetermined injection holding pressure switching condition is met, where the control contains the following: a molded part position setting unit that sets a process value related to a process position of the molded part (1) and sets the process position of the molded part according to the set process value; and a correction value setting unit which sets a correction value (Δs) for correcting the process position of the molded part (1), and wherein the injection-molded part position setting unit uses the correction value (Δs) to set the dosing completion position (X m ) and the injection speed switching position (X v ) as the process position of the injection-molded part (1) in each predetermined cycle. [2] Control of the injection molding machine (M) according to claim 1, wherein the injection pressure switching condition (X v ) is determined on the basis of the position of the injection-molded part (1), and the injection-molded part position setting unit further determines an injection holding pressure switching position (X p ) as the process position of the injection-molded part (1). [3] The control system of the injection molding machine (M) according to claim 1 or 2, wherein the molded part position setting unit reads the correction value (Δs) every predetermined cycle and determines a new process value by adding or subtracting the read correction value (Δs) to or from the process value to adjust the process position of the molded part (1) based on the new process value. [4] The control system of the injection molding machine (M) according to claim 1 or 2, wherein the correction value setting unit sets a correction value (Δs) corresponding to the number of cycles to adjust the process position of the molded part (1) based on a result obtained by adding or subtracting the read-out correction value (Δs) to or from the process value. [5] The control of the injection molding machine (M) according to claim 1 or 2, wherein the predetermined number of cycles is the number of cycles previously stored in a storage device or the number of cycles inputted from an input unit.

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