JP7467183B2 - Molding machine - Google Patents

Description

The present invention relates to a molding machine that injects molding material into a mold to produce a molded product.

Conventionally, injection molding machines have been known that drive a servo motor to inject molding material molten in a heated cylinder into the cavity of a clamped mold (see, for example, Patent Documents 1 and 2).

In addition, such injection molding machines are equipped with a servo amplifier that controls the drive of the servo motor. The servo amplifier performs feedback control to increase or decrease the power supplied to the servo motor according to the control parameters so that the difference between the target value (e.g., target speed, target pressure, target torque, etc.) obtained from the control device and the actual value detected by the sensor approaches zero.

Japanese Patent Application Laid-Open No. 06-055598 JP 2007-130978 A

Here, if the responsiveness of the feedback control is low, it will not be able to follow the commands of the control device properly. On the other hand, if the responsiveness of the feedback control is too high, the servo motor will oscillate. And since the appropriate value of the responsiveness of the feedback control varies depending on the type of molding material and the shape (thickness, etc.) of the molded product, experience and skill are required to adjust it. Such issues can also occur with electric die casting machines, which inject molten metal into a mold to form a molded product.

The present invention was made to solve these problems with the conventional technology, and its purpose is to provide a technology that adjusts the responsiveness of feedback control to an appropriate value in a molding machine equipped with a servo motor.

In order to solve the above-mentioned problems, the present invention provides a molding machine that includes a mold clamping device that opens and closes a mold and clamps the mold, an injection device that injects a measured amount of molding material into the cavity of the clamped mold, an ejector device that ejects a molded product from the mold that has been opened, and a control device that controls the mold clamping device, the injection device, and the ejector device to repeatedly perform a molding operation to mold a molded product, wherein each of the mold clamping device, the injection device, and the ejector device is provided with a servo motor, a sensor that detects actual measured values of physical quantities that change due to the operation of the servo motor, and a control device that controls the servo motor according to control parameters so that the difference between a target value obtained from the control device and the actual measured value detected by the sensor approaches zero. and a servo amplifier that performs feedback control to increase or decrease the power supplied to the motor, and the control device, in the molding operation, provides the target value to the servo amplifier to operate the servo motor, and determines whether the actual measurement value detected by the sensor is oscillating. If it is determined that the actual measurement value is oscillating, the control parameter is changed in a direction that reduces responsiveness to the target value and the molding operation is performed again. If the actual measurement value oscillates in the first molding operation and does not oscillate in the Nth (N is an integer equal to or greater than 2) molding operation, the control device performs the molding operation after the (N+1)th time with the control parameter used in the Nth molding operation.

According to the present invention, the responsiveness of the feedback control of the servo motor installed in the molding machine can be adjusted to an appropriate value.

FIG. 1 is a side view of an injection molding machine according to an embodiment of the present invention. FIG. 2 is a hardware block diagram of the injection molding machine. 1 is a flowchart of an automatic molding process. 13 is a flowchart of a tuning instruction process. 13 is a flowchart of a parameter determination process. 1 is a diagram showing the relationship between ideal behavior and actual behavior of a servo motor;

The injection molding machine 10 according to the present invention will be described below with reference to the drawings. The injection molding machine 10 is a device that injects a measured amount of molding material into a mold to form an injection molded product. However, a specific example of the molding machine is not limited to the injection molding machine 10, and may be an electric die-casting machine that injects molten metal (molding material) into a mold to form a molded product.

Figure 1 is a side view of an injection molding machine 10 according to this embodiment. Figure 2 is a hardware block diagram of the injection molding machine 10. As shown in Figures 1 and 2, the injection molding machine 10 mainly includes a mold clamping device 20, an injection device 30, an ejector device 40, and a control device 60.

The clamping device 20 opens, closes, and clamps the mold 21. Specifically, the clamping device 20 mainly comprises a fixed die plate 23 that supports the fixed mold 22, and a movable die plate 25 that supports the movable mold 24. The fixed mold 22 and the movable mold 24 are supported so as to face each other in the left-right direction (horizontal direction) of the injection molding machine 10.

The movable die plate 25 moves left and right along the tie bars 27 as the driving force of the die opening/closing motor 28 is transmitted through the toggle link mechanism 26. When the movable die plate 25 moves leftward, the fixed die 22 and the movable die 24 move apart. On the other hand, when the movable die plate 25 moves rightward, the fixed die 22 and the movable die 24 come into contact with each other, forming a cavity (internal space) inside the die 21. Then, when further pressure is applied in a direction that moves the movable die plate 25 rightward, the fixed die 22 and the movable die 24 are clamped.

The injection device 30 plasticizes, measures, and injects the molding material. In this embodiment, the injection device 30 is arranged horizontally separated from the mold clamping device 20 (to the right of the mold clamping device 20). The injection device 30 mainly comprises a heating cylinder 31, a screw 32, a hopper 33, and a hopper block 34.

The heating cylinder 31 is a cylindrical member that extends in the left-right direction of the injection molding machine 10. The heating cylinder 31 mainly includes a screw passage 35 and a nozzle 36. In addition, a band heater (not shown) that heats the heating cylinder 31 is attached to the outer circumferential surface of the heating cylinder 31.

The screw passage 35 is a linear space that extends axially (longitudinal) inside the heating cylinder 31. The screw passage 35 is connected to the outside of the heating cylinder 31 through a nozzle 36 provided at the tip (front end) of the heating cylinder 31. In other words, the screw passage 35 is a space that extends axially from the nozzle 36.

The screw 32 is a cylindrical member. A spiral groove is formed on the outer circumferential surface of the screw 32. The screw 32 is housed in the internal space of the heating cylinder 31 in a state in which it can move left and right (hereinafter referred to as "advance and retreat") and rotate in the injection molding machine 10. The screw 32 advances and retreats when the driving force of the injection motor 37 is transmitted to it, and rotates when the driving force of the metering motor 38 is transmitted to it.

The hopper 33 is a funnel-shaped member that stores the raw molding material. The hopper block 34 is a member that supports the heating cylinder 31 and the hopper 33. The molding material stored in the hopper 33 is supplied to the screw passage 35 of the heating cylinder 31 through an opening at the bottom end. The molding material used in this injection molding machine 10 is molded into a cylindrical shape that contains fibers, for example.

The ejector device 40 is a device that ejects an injection molded product from the open movable mold 24. The ejector device 40 mainly comprises an ejector pin (not shown) provided in the movable mold 24, and an ejector motor 41 (see FIG. 2) that causes the ejector pin to extend and retract. The driving force of the ejector motor 41 is transmitted to the ejector pin, causing it to protrude toward the inner surface of the movable mold 24, thereby releasing the injection molded product from the mold.

As shown in FIG. 2, the control device 60 includes a CPU (Central Processing Unit) 61, which is a calculation means, a ROM (Read Only Memory) 62 that stores various programs, and a RAM (Random Access Memory) 63, which is a working area for the calculation means. The CPU 61 may then read and execute the programs stored in the ROM 62 to realize the various processes described below.

However, the specific configuration of the control device 60 is not limited to this, and may be realized by hardware such as an ASIC (Application Specific Integrated Circuit) or an FPGA (Field-Programmable Gate Array).

The control device 60 controls the operation of the entire injection molding machine 10. More specifically, it controls the driving of the mold opening/closing motor 28, the injection motor 37, the metering motor 38, and the ejector motor 41. The injection motor 37 drives (rotates) under the control of a servo amplifier 64. Although not shown, the driving of the mold opening/closing motor 28, the metering motor 38, and the ejector motor 41 is also similarly controlled by a servo amplifier. That is, the mold clamping device 20, the injection device 30, and the ejector device 40 each include a servo motor and a servo amplifier that controls the driving of the servo motor.

The servo amplifier 64 controls the drive of the injection motor 37 by feedback control. Feedback control is a process of increasing or decreasing the power (e.g., current value) supplied to the injection motor 37 according to control parameters so that the difference between the target value (e.g., target speed, target pressure, target torque, etc.) obtained from the control device 60 and the actual value detected by the sensor (rotary encoder 65, load cell 66) approaches zero.

More specifically, in one feedback control (PID control), the servo amplifier 64 increases the power supplied to the injection motor 37 when the actual measurement value is lower than the target value, and decreases the power supplied to the injection motor 37 when the actual measurement value is higher than the target value. The control parameter for determining the range of power fluctuation (increase range, decrease range) in one feedback control is called the "proportional control gain." For example, the larger the P gain of the proportional control gain is, the better the responsiveness is, and the smaller the P gain is, the worse the responsiveness is.

The servo amplifier 64 also repeatedly executes the above-mentioned feedback control at a predetermined time interval. The control parameter for determining the execution interval of the feedback control (in other words, the number of times the feedback control is executed per unit time) is called the "response frequency." In other words, the higher the response frequency, the better the responsiveness, and the lower the response frequency, the worse the responsiveness.

The rotary encoder 65 is a sensor that detects the forward speed of the screw 32 as an actual measured value of a physical quantity. More specifically, the rotary encoder 65 outputs a pulse signal corresponding to the rotation of the injection motor 37 to the control device 60 and the servo amplifier 64. The control device 60 and the servo amplifier 64 then determine the forward speed of the screw 32 based on the number of pulse signals output per unit time.

The load cell 66 is a sensor that detects the pressure applied to the screw 32 as an actual measured value of a physical quantity. More specifically, the load cell 66 outputs a pressure signal corresponding to the pressure applied to the screw 32 to the control device 60 and the servo amplifier 64. In other words, the rotary encoder 65 and the load cell 66 are sensors that detect the actual measured value of a physical quantity that changes due to the operation of the injection motor 37.

Furthermore, a display input device (input device) 67 is connected to the control device 60. The display input device 67 is a user interface that includes a display that displays various information to be notified to the operator, and buttons, switches, dials, etc. that accept operations by the operator. The display input device 67 may also include a touch panel superimposed on the display. The display input device 67 accepts input operations by the operator and outputs an input signal corresponding to the accepted input operation to the control device 60.

Figure 3 is a flowchart of the automatic molding process. The automatic molding process is a process for continuously molding multiple injection molded products by repeatedly executing a molding operation including steps S11 to S16. The control device 60 starts the automatic molding process in response to receiving an instruction to start the automatic molding process together with the molding conditions through the display input device 67. Note that at the start of the automatic molding process, a measured amount of molding material is stored in the space ahead of the screw 32 in the screw passage 35.

First, the control device 60 drives the mold opening/closing motor 28 to cause the mold clamping device 20 to close and clamp the mold 21 (S11). This forms a cavity inside the mold 21. Step S11 is an example of a mold clamping process.

Next, the control device 60 drives the injection motor 37 to advance the screw 32 at the target speed (S12). As a result, the molding material stored in the screw passage 35 is injected into the cavity of the mold 21 by the screw 32 advancing at the target speed. Step S12 is an example of an injection process.

Next, the control device 60 supplies power to the injection motor 37 so that the screw 32 presses the molding material at a predetermined target pressure (S13). This applies pressure to the injection molded product in the cavity. As a result, the cavity is filled with the molding material without any gaps, preventing molding defects. Step S14 is an example of a pressure holding process. Furthermore, the control device 60 continues the pressure holding process (S13) until a predetermined pressure holding time has elapsed (S14: No).

Next, when the dwell time has elapsed (S14: Yes), the control device 60 drives the metering motor 38 to rotate the screw 32 (S15). This causes the molding material supplied from the hopper 33 to the screw passage 35 to move forward of the screw 32 through the spiral groove. The molding material is also melted as it moves forward through the screw passage 35, and is stored as molding material in the space in front of the screw 32 in the screw passage 35. Step S15 is an example of a metering process.

Next, the control device 60 waits until a predetermined time (hereinafter referred to as the "cooling period") has elapsed since the end of the pressure holding step (S14) before opening the mold 21. This cooling period is the time required for the molding material injected into the mold 21 to cool and solidify.

Next, when the cooling period has elapsed, the control device 60 drives the mold opening/closing motor 28 to cause the mold clamping device 20 to open the mold 21 (S16). The control device 60 also causes the ejector device 40 to release the injection molded product in the opened mold 21 from the movable mold 24, and has the product removed by a robot arm (not shown). Step S16 is an example of a mold opening process.

Next, the control device 60 determines whether or not a predetermined number of injection molded products have already been molded (i.e., whether or not molding is complete) (S17). If the control device 60 determines that molding is not complete (S17: No), it executes the processes from step S11 onwards again. On the other hand, if the control device 60 determines that molding is complete (S17: Yes), it ends the automatic molding process.

Next, the process of tuning (optimizing) the control parameters set in the servo amplifier 64 will be described with reference to Figures 4 to 6. Figure 4 is a flowchart of the tuning instruction process. Figure 5 is a flowchart of the parameter determination process. Figure 6 is a diagram showing the relationship between the ideal behavior (dashed line) and the actual behavior (solid line) of the servo motor.

The tuning instruction process is a process that allows the operator to specify the servo motor to be tuned. For example, when the [Tune] button displayed on the display input device 67 is pressed during execution of the automatic molding process, the control device 60 executes the tuning instruction process shown in FIG. 4.

Next, the control device 60 displays the [All Tuning] button and the [Specified Tuning] button on the display/input device 67, and waits to execute subsequent processing until either one of them is pressed (S22). The [All Tuning] button is a button for instructing tuning of all of the multiple servo motors mounted on the injection molding machine 10 (all tuning instruction). The [Specified Tuning] button is a button for instructing tuning of some of the multiple servo motors mounted on the injection molding machine 10 (specified tuning instruction).

When the [All Tuning] button is pressed (S22: All), the control device 60 executes the parameter determination process shown in FIG. 5 for all servo motors (S23). On the other hand, when the [Specified Tuning] button is pressed (S22: Specified), the control device 60 executes the parameter determination process shown in FIG. 5 for only the servo motor specified through the display input device 67 (S24) (S25).

More specifically, the control device 60 displays buttons corresponding to each of the multiple servo motors mounted on the injection molding machine 10 (e.g., a "mold opening/closing motor" button, an "injection motor" button, a "metering motor" button, and an "ejector motor" button) on the display/input device 67 and has the operator press these buttons (S24). Although not shown in the figures, the control device 60 may also have the operator specify the type of operation of the servo motor to be tuned (e.g., S11 to S13, S15, and S16 in FIG. 3).

The parameter determination process is performed during the repeated execution of the molding operation (steps S11 to S16 in FIG. 3). Here, we will explain the process of determining the response frequency when the screw 32 is advanced at the target speed (S12) when the [Specified Tuning] button is pressed in step S22 and the [Injection Motor] button is pressed in step S24.

First, in step S12 of the first molding operation (i.e., N=1), the control device 60 provides the servo amplifier 64 with a target speed as a target value, and causes the servo amplifier 64 to operate the injection motor 37 (S31). In step S31, the servo amplifier 64 feedback controls the injection motor 37 with the initial values of the control parameters (proportional control gain, response frequency).

Here, the ideal behavior of the injection motor 37 (target value given by the control device 60) shown by the dashed line in Figure 6 includes a rise section where the forward speed increases to the target speed, a steady section where the forward speed is constant at the target speed, and a fall section where the forward speed decreases from the target speed toward zero. However, the actual behavior of the injection motor 37 shown by the solid line in Figure 6 (actual measured value detected by the sensor) deviates from the ideal behavior.

Therefore, the servo amplifier 64 executes feedback control to bring the solid line in FIG. 6 closer to the dashed line. However, if the responsiveness of the feedback control is low, the deviation between the solid line and the dashed line remains large, as shown in the upper left diagram of FIG. 6. On the other hand, if the responsiveness of the feedback control is too high, the actual speed of the injection motor 37 will fluctuate wildly around the target speed, as shown in the lower right diagram of FIG. 6 (hereinafter, this type of behavior will be referred to as "oscillating").

Then, while the servo amplifier 64 is operating the injection motor 37, the control device 60 determines whether the actual speed (actual measured value) of the injection motor 37 is oscillating based on the pulse signal output from the rotary encoder 65 (S32).

Next, if the control device 60 determines that oscillation occurred during the first molding operation (S32: Yes), it executes the processes of steps S33 to S37. First, the control device 60 adds 1 to the variable N (S33). Next, the control device 60 sets a response frequency that is smaller than the current response frequency as a new response frequency in the servo amplifier 64 (S34).

That is, in step S34, the control device 60 changes the response frequency in a direction that reduces the responsiveness of the feedback control. As one example, the control device 60 may determine a new response frequency by subtracting a fixed value from the current response frequency. As another example, the control device 60 may determine a new response frequency by multiplying the current response frequency by a fixed value (<1).

The control device 60 then executes steps S13 to S16 and S11, and waits to execute the parameter determination process until returning to step S12 again. Then, in step S12 of the Nth molding operation, the control device 60 operates the injection motor 37 again (S35). The process of step S35 is the same as step S31, except that the control parameters have been changed. That is, in step S35, the servo amplifier 64 feedback-controls the injection motor 37 according to the response frequency changed in the previous step S34.

Next, the control device 60 determines whether or not the actual speed (actual measured value) of the injection motor 37 is oscillating during the Nth molding operation (S36). The process of step S36 is the same as step S32. If the control device 60 determines that oscillation is occurring during the Nth molding operation (S36: Yes), it executes the processes from step S33 onwards again. On the other hand, if the control device 60 determines that oscillation is not occurring during the Nth molding operation (S36: No), it determines the response frequency used during the Nth molding operation as the response frequency to be used during the (N+1)th and subsequent molding operations (S37).

That is, if the actual measurement value oscillates during the first molding operation (S32: Yes), the control device 60 repeats the molding operation while gradually changing the control parameters in a direction that reduces responsiveness until the oscillation subsides (S36: No) (S34, S35). As a result, as shown in the upper right diagram of FIG. 6, the oscillation of the actual measurement value disappears and the actual measurement value becomes closer to the target value. The control device 60 then determines the control parameters at the timing when the oscillation subsides as the control parameters to be used in the (N+1)th molding operation and thereafter (S37). The control device 60 then ends the parameter determination process.

On the other hand, if the control device 60 determines that oscillation did not occur during the first molding operation (S32: No), it executes the processes of steps S38 to S42. First, the control device 60 adds 1 to the variable N (S38). Next, the control device 60 sets a response frequency that is greater than the current response frequency as a new response frequency in the servo amplifier 64 (S39).

That is, in step S39, the control device 60 changes the response frequency in a direction that increases the responsiveness of the feedback control. As one example, the control device 60 may add a fixed value to the current response frequency to determine the new response frequency. As another example, the control device 60 may multiply the current response frequency by a fixed value (>1) to determine the new response frequency.

The control device 60 then executes steps S13 to S16 and S11, and waits to execute the parameter determination process until returning to step S12 again. Then, in step S12 of the Nth molding operation, the control device 60 operates the injection motor 37 again (S40). The process of step S40 is the same as step S31, except that the control parameters have been changed. That is, in step S40, the servo amplifier 64 feedback-controls the injection motor 37 according to the response frequency changed in the previous step S39.

Next, the control device 60 determines whether or not the actual speed (actual measured value) of the injection motor 37 is oscillating during the Nth molding operation (S41). The process of step S41 is the same as step S32. If the control device 60 determines that the injection motor 37 is not oscillating during the Nth molding operation (S41: No), it executes the processes from step S38 onwards again. On the other hand, if the control device 60 determines that the injection motor 37 is oscillating during the Nth molding operation (S41: Yes), it determines the response frequency used during the (N-1)th molding operation as the response frequency to be used during the (N+1)th molding operation and thereafter (S42).

In other words, if the actual measurement value does not oscillate in the first molding operation (S32: No), the control device 60 repeats the molding operation while gradually changing the control parameters to improve responsiveness until oscillation occurs (S41: Yes) (S39, S40). This results in the actual measurement value being closer to the target value, as shown in the upper right diagram of FIG. 6. The control device 60 then determines the control parameters immediately before oscillation occurs as the control parameters to be used in the (N+1)th and subsequent molding operations (S42). The control device 60 then ends the parameter determination process.

The control device 60 continues the molding operation even after the control parameters have been determined for the Nth molding operation (i.e., the parameter determination process has ended). However, for the (N+1)th and subsequent molding operations, the parameter control process is not performed, and the control parameters determined in steps S37 and S42 are used. Note that N is an integer equal to or greater than 2, and is a value that changes each time the parameter determination process is performed.

The above embodiment provides the following advantages, for example:

According to the above embodiment, it is possible to obtain the most responsive control parameters within the range where oscillation does not occur. As a result, even if the type of molding material or the shape (thickness, etc.) of the injection molded product changes, the responsiveness of the feedback control can be set to an appropriate value.

In addition, according to the above embodiment, the response frequency in the injection process is adjusted depending on whether or not the forward speed of the screw 32 oscillates, so the molding material can be injected into the cavity at an appropriate speed. As a result, the quality of the injection molded product can be maintained.

Note that the tuning in the parameter determination process is not limited to the response frequency in the injection process (S12). In other words, the control parameter tuned in the injection process (S12) is not limited to the response frequency, and may be the proportional control gain.

As another example, the control device 60 may determine a proportional control gain suitable for applying a target pressure to the screw 32 in the pressure holding process (S13). In this case, the control device 60 may provide the target pressure as a target value to the servo amplifier 64 in steps S31, S35, and S40 of FIG. 5 to operate the injection motor 37. The control device 60 may also determine whether the pressure detected by the load cell 66 is oscillating in steps S32, S36, and S41. The control device 60 may also reduce, for example, the P gain as the proportional control gain in step S34, and increase the P gain in step S39. However, the control parameter tuned in the pressure control (S14) is not limited to the proportional control gain, and may be the response frequency.

As another example, the control device 60 may determine control parameters suitable for clamping the mold 21 in the mold clamping process (S11). As another example, the control device 60 may determine control parameters suitable for weighing the molding material in the weighing process (S15). As another example, the control device 60 may determine control parameters suitable for opening the mold 21 or control parameters suitable for ejecting the injection molded product in the mold opening process (S16). As yet another example, the control device may optimize control parameters of other servo motors mounted on the injection molding machine 10.

In addition, according to the above embodiment, since the presence or absence of oscillation is determined in the steady section, the presence or absence of oscillation can be determined more appropriately than when the presence or absence of oscillation is determined in the rising section and the falling section. As a result, it is possible to bring the control parameters closer to the optimal values.

Furthermore, according to the above embodiment, the operator can select between a specified tuning instruction and a full tuning instruction. Then, in step S25, only the operation of the servo motor specified by the operator is optimized. On the other hand, in step S23, the operation of all servo motors mounted on the injection molding machine 10 is optimized. In this case, the control device 60 can perform optimization of the control parameters in parallel in each of the repeatedly executed steps S11 to S16.

Furthermore, the parameter determination process is not limited to being executed during the automatic molding process. As another example, the control device 60 may execute the parameter determination process when the servo motors are in the servo ON state during the process of molding one molded product (i.e., while steps S11 to S16 are executed only once). In other words, the control device 60 can also optimize the control parameters when each servo motor is positioning.

More specifically, when the operator notices that the screw 32 is vibrating in step S13, he or she may instruct the execution of the parameter determination process via the display/input device 67. In this case, the processes of steps S31 to S37 in FIG. 5 are executed.

The above-described embodiments are illustrative examples of the present invention, and are not intended to limit the scope of the present invention to these embodiments. Those skilled in the art can implement the present invention in various other forms without departing from the spirit of the present invention.

10... injection molding machine, 20... mold clamping device, 21... mold, 22... fixed side mold, 23... fixed die plate, 24... movable side mold, 25... movable die plate, 26... toggle link mechanism, 27... tie bar, 28... mold opening and closing motor, 30... injection device, 31... heating cylinder, 32... screw, 33... hopper, 34... hopper block, 35... screw passage, 36... nozzle, 37... injection motor, 38... metering motor, 40... ejector device, 41... ejector motor, 60... control device, 61... CPU, 62... ROM, 63... RAM, 64... servo amplifier, 65... rotary encoder, 66... load cell, 67... display input device (input device)

Claims (6)

A molding machine comprising a mold clamping device which opens and closes a mold and clamps the mold, an injection device which injects a measured amount of molding material into a cavity of the clamped mold, an ejector device which ejects a molded product from the opened mold, and a control device which controls the mold clamping device, the injection device, and the ejector device to repeatedly perform a molding operation for molding a molded product,
Each of the mold clamping device, the injection device, and the ejector device is
A servo motor;
a sensor for detecting an actual value of a physical quantity that changes due to the operation of the servo motor;
a servo amplifier that executes feedback control to increase or decrease the power supplied to the servo motor in accordance with a control parameter so that a difference between a target value acquired from the control device and the actual value detected by the sensor approaches zero;
The control device includes:
In the molding operation, the target value is given to the servo amplifier to operate the servo motor, and it is determined whether or not the actual measurement value detected by the sensor oscillates;
When it is determined that the actual measurement value is oscillating, the control parameter is changed in a direction to reduce responsiveness to the target value, and the molding operation is performed again.
A molding machine characterized in that, when the actual measured value oscillates during a first molding operation and does not oscillate during an Nth (N is an integer equal to or greater than 2)th molding operation, the molding operation from (N+1) onwards is performed using the control parameters used in the Nth molding operation. The control device includes:
When it is determined that the actual measurement value does not oscillate, the control parameter is changed in a direction to increase the responsiveness, and the molding operation is performed again.
The molding machine described in claim 1, characterized in that if the actual measured value does not oscillate during the first molding operation and oscillates during the Nth (N is an integer greater than or equal to 2)th molding operation, the molding operation from the (N+1)th operation onwards is performed using the control parameters used in the (N-1)th operation. the injection device includes a screw that moves back and forth within a heating cylinder that communicates with the cavity by transmitting a driving force of the servo motor;
The sensor detects a forward speed of the screw as the actual measured value of a physical quantity,
In the injection step of advancing the screw at a predetermined target speed to inject the molding material measured in the heating cylinder into the cavity, the control device
The target speed is provided as the target value to the servo amplifier to advance the screw;
3. The molding machine according to claim 1, wherein the control parameter is changed depending on whether or not the forward speed of the screw oscillates, as detected by the sensor. The sensor detects a pressure applied to the screw as the actual measured value of a physical quantity,
The control device controls the screw to press the molding material injected into the cavity in the injection process at a predetermined target pressure in a pressure holding process.
The target pressure is applied to the servo amplifier as the target value to cause the screw to press the molding material;
4. The molding machine according to claim 3, wherein the control parameters are changed depending on the presence or absence of oscillation of the pressure detected by the sensor. the operation includes a rising section in which the physical quantity rises toward the target value, a falling section in which the physical quantity falls from the target value, and a steady section between the rising section and the falling section,
5. The molding machine according to claim 1, wherein the control device determines whether the actual measurement value in the steady-state section is oscillating. an input device that receives a total tuning instruction for instructing tuning of all of the plurality of servo motors mounted on the molding machine and a designated tuning instruction for instructing tuning of a part of the plurality of servo motors,
The control device includes:
adjusting all of the control parameters of the plurality of servo motors when the full tuning instruction is received through the input device;
The molding machine according to any one of claims 1 to 5, characterized in that, when the designated tuning instruction is received through the input device, the control parameters of only the servo motor designated through the input device are adjusted.

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