JPH0773866B2 - Injection molding machine - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of reducing a mold clamping force to bring a movable platen closer to the fixed platen, and thereafter, greatly changing the mold clamping force to bring the movable platen closer to a fixed platen. Injection molding machine.

[0002]

2. Description of the Related Art In a conventional injection molding machine, in order to change the mold clamping force from a low pressure mold protecting process having a small mold clamping force to a high pressure mold clamping process having a large mold clamping force, the injection molding machine main body is used. A cam plate is provided on the side so as to be movable in the advancing and retracting direction of the movable plate, and a limit switch is fixedly provided on the movable plate side (for example, a cross head of a toggle mechanism) facing the cam plate. Then, the position of the cam plate is adjusted and fixed, and when the movable plate advances to a predetermined position, the limit switch is turned on by the cam plate, and the movable plate is driven forward based on this ON signal. The fluid pressure (hydraulic pressure) supplied to the actuator (hydraulic cylinder) is switched between high pressure and high speed to clamp the fixed mold and the movable mold at high speed and high pressure.

[0003]

However, in the above-mentioned conventional injection molding machine, when the position of the cam plate is adjusted and the limit switch fixed to the movable plate comes to the position of the cam plate, the fluid pressure is reduced. Since it is designed to switch to high pressure and high speed side, the position of the cam plate must be adjusted every time the fixed mold and the movable mold with different mold thickness are replaced, and this adjustment work is very troublesome. Met.

Further, since the position of the cam plate regulates the changing position of the operating state of the actuator for driving the movable plate, it is necessary to adjust the position extremely accurately, and this position adjustment is inaccurate. If the transition to the high pressure and high speed side is too fast, it is not possible to detect when a foreign object is caught between the fixed mold and the movable mold, and if the transition to the high pressure and high speed side is too slow. There is a problem that a predetermined mold clamping force cannot be obtained.

The present invention has been made in view of the above circumstances, and provides an injection molding machine capable of easily and accurately adjusting a change point for increasing a mold clamping force by an actuator for driving a movable plate. The purpose is to do.

[0006]

The injection molding machine of the present invention comprises:
A fixed plate to which a fixed mold is attached, a movable plate to which a movable mold is attached and which is provided so as to be movable back and forth with respect to the fixed plate, an end plate provided behind the movable plate, and this end plate. A toggle mechanism interconnecting the movable plate and moving the crosshead forward and backward with respect to the end plate to move the movable plate forward and backward with respect to the end plate; and a forward and backward drive of the crosshead with respect to the end plate. An actuator for controlling the mold clamping force between the movable mold and the fixed mold by the actuator, and position detecting means for detecting a relative position of the crosshead with respect to the end plate, The movable platen is moved by reducing the mold clamping force of the actuator by the actuator operation control means. In the injection molding machine in which the movable platen is brought close to the fixed platen and the mold is clamped by the actuator operation control means, the mold clamping force is greatly changed by the actuator operation control means. With the toggle mechanism extended, the end plate is moved forward to bring the movable mold into contact with the fixed mold, and the end plate is moved relative to the fixed plate to retighten the actuator to operate the actuator. When the cross head is moved forward to move the movable plate forward, the movable mold and the fixed mold contact each other.
The mold clamping force by the actuator exceeds the above small value.
In the stores the read write memory means reads the position data indicating the position of the cross head detected by the position detecting means, conventional clamping step when it is detected that the,
Position data indicating the position of the crosshead detected by the position detection means when the actuator is operated to move the crosshead forward and the movable mold is moved forward, and position data stored in the read storage means. DOO seek changes in the clamping force of the actuator based on the control means to control the actuator operation control means so as to increase the clamping force of the movable die by the actuator on the basis of this change It is characterized by having.

[0007]

According to the injection molding machine of the present invention, when the crosshead is moved forward and the movable platen is moved forward during setup, the fixed mold and the movable mold come into contact with each other so that the actuator is actuated.
When it is detected that the mold clamping force by the actuator exceeds the small value , the position data of the crosshead detected by the position detection means is read and stored in the read storage means. Then, in the normal mold clamping process, the control unit changes the mold clamping force based on the position data detected by the position detection unit when the movable platen is moved forward and the position data stored in the read storage unit. The actuator actuation control means is controlled so as to obtain a point and increase the mold clamping force based on this change point.

In this way, the fixed mold and the movable mold are brought into contact with each other at the time of setup, and the position data of the crosshead at that time are simply read and stored in the read storage means, and based on the read position data. The change point of the mold clamping force can be obtained, and the change position of the mold clamping force can be easily and accurately adjusted. In particular, the changes are the thickness of the mold, etc.
Need to be tweaked when
Work is done automatically, accuracy of adjustment and short setup time
Can be reduced.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An injection molding machine according to an embodiment of the present invention will be described below with reference to the drawings.

The overall construction of the injection molding machine of this embodiment will be described with reference to FIG.

A fixed platen 2 to which one fixed mold 1 is attached is fixed to the main body of the injection molding machine, and a movable platen 3 to which the other movable mold 4 is attached is provided facing the fixed platen 2. There is. The movable platen 3 is provided so as to be able to move forward or backward with respect to the fixed platen 2 along a tie bar 5 attached at a right angle to the platen surface of the fixed platen 2. Further, an end plate 6 is attached behind the movable plate 3 so as to be able to move forward or backward along the tie bar 5 .

The end plate 6 and the movable platen 3 are connected to each other by a toggle mechanism 7. A mold clamping cylinder (corresponding to an actuator of the present invention) 9 is fixed to the end plate 6, and a piston rod of the mold clamping cylinder 9 is connected to a crosshead 8 in the toggle mechanism 7.

An electromagnetic switching valve 10 is attached to the mold clamping cylinder 9.
And a pump 12 are connected via an electromagnetic proportional flow valve 11. A bypass passage leading to the tank 15 is connected to a passage between the electromagnetic proportional flow valve 11 and the pump 12, and a main relief valve 13 is interposed in the bypass passage to communicate with the mold clamping cylinder 9. The maximum value of hydraulic pressure in the passage is regulated. A bypass passage communicating with the tank 15 is connected to the main relief valve 13, and an electromagnetic proportional pressure valve 14 is interposed in this bypass passage. A pressure sensor 32 is provided in the passage between the electromagnetic switching valve 10 and the mold clamping cylinder 9 to detect the pressure in this passage, that is, the pressure chamber of the mold clamping cylinder 9. The solenoid switching valve 1
0, the electromagnetic proportional flow valve 11, the main relief valve 13, and the electromagnetic proportional pressure valve 14 constitute the actuator operation control means of the present invention.

A rack 25 is fixed to the crosshead 8, and a rotary encoder (corresponding to position detecting means) 24 fixed to the end plate 6 is connected to the rack 25.

The structure in the vicinity of the crosshead 8 will be described with reference to FIGS. 2 and 3. A plate-shaped bracket 26 is fixed by bolts 27 from the end surface of the end plate 6 toward the front. In the middle of the bracket 26,
A rotary encoder 24 is attached orthogonally to the plate surface, and a pinion 28 is fixed to the input shaft of this rotary encoder 24. The crosshead 8 is slidably attached along a guide bar 29 provided so as to project forward from the end plate 6, and the crosshead 8 is formed with a convex portion 8a projecting in the radial direction. A rack 25 that is screwed to the pinion 28 is attached to the convex portion 8a with a bolt or the like. And
When the crosshead 8 moves forward or backward with respect to the end plate 6, this forward / backward displacement is transmitted as a rotary displacement to the rotary encoder 24 via the rack 25 and the pinion 28, and the end plate 6 of the crosshead 8 is transmitted.
The position with respect to is detected.

As shown in FIG. 1, the end plate 6
A limit switch 23 with which the crosshead 8 abuts when the toggle mechanism 7 is maximally extended is attached to the.

The injection molding machine of this embodiment is provided with a control device 16 as shown in FIG.

In the control device 16, a mold closing speed setting device 18, a mold closing pressure setting device 19, a high pressure mold closing pressure setting device 20, and a pressure confirmation setting device 21 are set via a set value input / output circuit 17.
And the high voltage start setting device 22 are connected.

The limit switch 23 is connected to the control device 16 via a limit switch input circuit 30, the rotary encoder 24 is connected to the control device 16 via an encoder input circuit 31, and the pressure sensor 32 is connected to the pressure sensor. The electromagnetic switching valve 10 is connected via an input circuit 33, the electromagnetic switching valve 10 is connected via an electromagnetic valve output circuit 34, and the electromagnetic proportional flow valve 11 and the electromagnetic proportional pressure valve 14 are connected via a proportional valve output circuit 35. ing. further,
An adjustment mode switch 36 and a start switch 37 are connected to the control device 16 via a switch input circuit 38. Here, the adjustment mode switch 36 is turned on when performing the setup operation, and the start switch 37 is turned on when starting the mold clamping operation.

Next, the operation of this embodiment will be described.

First, the procedure for mold clamping setup will be described with reference to FIG.

As shown in (a), the end plate 6 is retracted while the toggle mechanism 7 is fully extended to widen the distance between the fixed platen 2 and the movable platen 3, and the fixed mold 1 and the movable mold 1 are moved. Attach 4.

As shown in (b), the end plate 6 is moved forward from the state of (a), and the mating surfaces of the fixed mold 1 and the movable mold 4 are brought into contact with each other with the toggle mechanism 7 fully extended. Let

As shown in (c), in the state of (b), the electromagnetic switching valve 10 is switched to the b side of FIG. 1 to supply hydraulic oil to the mold clamping cylinder 9 to drive the crosshead 8 of the toggle mechanism 7. The movable platen 3 is retracted to the end plate 6 side, the toggle mechanism 7 is contracted, the movable platen 3 is drawn to the end plate 6 side, and the fixed mold 1 and the movable mold 4 are once opened.

As shown in (d), the end plate 6 is advanced by a predetermined amount in the state of (c). This advance amount is set for each of the fixed mold and the movable mold so that a predetermined mold clamping force is generated when the mold is closed, and corresponds to a so-called tightening amount.

As shown in (e), in the state of (d), the electromagnetic switching valve 10 is switched to the side a in FIG. 1 to supply hydraulic oil to the mold clamping cylinder 9 to drive the crosshead 8 of the toggle mechanism 7. The movable platen 3 is advanced toward the end plate 6 side, the toggle mechanism 7 is extended, and the movable platen 3 is advanced from the end plate 6 side to close the fixed mold 1 and the movable mold 4.

Here, a so-called low-pressure mold protection process is performed at a position slightly before the contact surfaces of the fixed mold 1 and the movable mold 4 are brought into contact with each other (this position can be set to an appropriate position). enter. That is, a signal is sent from the control device 16 to the electromagnetic proportional pressure valve 14, and the hydraulic pressure is switched to a small set value set by the mold closing pressure setting device 19, and the control device 16 switches the electromagnetic proportional flow valve 11 to the set value. A signal is sent, and the mold closing speed setter 18 is set to have a small set value. As a result, the forward load (clamping force) for moving the movable platen 3 forward and the forward speed become small, and when foreign matter is caught between the fixed mold 1 and the movable mold 4, the forward motion of the movable platen 3 stops. , Fixed mold 1 and movable mold 4
Protected from scratching.

The operation of the control device 16 as the control means of the present invention in the above process (e) will be described with reference to the flow chart shown in FIG.

Step 1 in FIG. 4 (S1 in the figure)
Enter. The same applies hereinafter), the adjustment mode switch 36
To turn on. As a result, the controller 16 selects the adjustment mode at the time of setup.

In step 2 in FIG. 4, the start switch 37 is turned on. As a result, hydraulic oil is supplied to the mold clamping cylinder 9, the toggle mechanism 7 extends, and the movable platen 3 begins to move forward.

In step 3 in FIG. 4, the mold closing operation is continuously performed as the toggle mechanism 7 is extended.

As shown in FIG. 5F, when the movable platen 3 is further advanced from the state of FIG. 5E, the mating surfaces of the fixed mold 1 and the movable mold 4 come into contact with each other. In the present embodiment, the contact of the mating surfaces is detected as shown in the flowchart of FIG. That is, as shown in step 4 of the flowchart of FIG. 4, the pressure value (pressure value for regulating the mold clamping force in the low pressure mold protection to a predetermined value) PS set by the pressure confirmation setting device 21 and the pressure The pressure value PA detected by the sensor 32 is compared, and the mold closing operation of step 3 is continued until PA ≧ PS, and when PA ≧ PS, the process proceeds to the next step 5. The step 4 is provided in view of the fact that the pressure value PA of the mold clamping cylinder 9 suddenly increases when the mating surfaces come into contact with each other.

Next, at step 5, the position data DE of the rotary encoder 24 when PA ≧ PS is read and stored in a predetermined memory. This step 5 corresponds to the read storage means of the present invention. Here, the position data DE is set to 0 when the crosshead 8 is most advanced, that is, when the crosshead 8 is farthest from the end plate 6, and has a positive value that sequentially increases when the crosshead 8 retracts from this position. There is.

In step 6 in FIG. 4, the position data DE read and stored in step 5 is added with a correction value α for correcting the thermal expansion of the fixed mold 1 and the movable mold 4 to obtain the position data. E15 is obtained and stored in a predetermined memory. Note that α is 0.02 mm in terms of length.

In step 7 in FIG. 4, a switching signal is issued from the control device 16 to operate the electromagnetic proportional pressure valve 14, and high-pressure mold clamping is performed. As shown in (g) of FIG. 5, the toggle mechanism 7 is advanced at high pressure, and the toggle mechanism 7 is completely extended to complete the mold clamping.

At this time, in step 8 of the flowchart shown in FIG. 4, it is determined whether or not the limit switch 23 fixed to the end plate 6 is turned on. This step 8 is provided to monitor the operation of the limit switch 23 provided at the position where the crosshead 8 comes into contact when the toggle mechanism 7 is fully extended to confirm whether the mold clamping is completely completed. It is a thing.

When the limit switch 23 is turned on, the process proceeds to step 9 in FIG. In step 9, the position data E15 obtained in step 6 is set in the high-voltage start setter 22 as a set value.

By performing the setup work as described above, the position data DE of the rotary encoder 24 when the mating surfaces of the fixed mold 1 and the movable mold 4 come into contact with the memory and the position data DE are corrected. The position data E15 corrected by adding the value α is stored.

Then, in the normal mold clamping process, the operation of the mold clamping cylinder 9 is controlled based on the obtained position data E15 to control the mold clamping process.

That is, from the control device 16 to the electromagnetic switching valve 1
1 is sent to switch to the b side in FIG. 1, hydraulic oil is supplied to the mold clamping cylinder 9 and the crosshead 8 of the toggle mechanism 7 is retracted so as to be closest to the end plate 6,
The movable platen 3 is most retracted with respect to the fixed platen 2 to prepare for the mold clamping process.

Then, in order to bring the mating surfaces of the fixed mold 1 and the movable mold 4 into contact with each other, a signal is sent from the control device 16 to the electromagnetic switching valve 10 to switch to the side a in FIG. Is supplied with hydraulic oil to move the crosshead 8 of the toggle mechanism 7 forward with respect to the end plate 6, and bring the movable platen 3 close to the fixed platen 2.

At this time, a signal is transmitted from the control device 16 to the electromagnetic proportional pressure valve 14 and is switched to set the hydraulic pressure of the hydraulic oil supplied to the mold clamping cylinder 9 to be a high pressure. A signal is transmitted from 16 to the electromagnetic proportional flow valve 11, and the flow rate of the hydraulic oil supplied to the mold clamping cylinder 9 is set to be large.

A short time before the mating surfaces of the fixed mold 1 attached to the fixed platen 2 and the movable mold 4 attached to the movable platen 3 come into contact with each other (this position is set to an appropriate position as described above). In the same manner as during the above-described setup, the low pressure mold protection process is started, a signal is transmitted from the control device 16 to the electromagnetic proportional pressure valve 14, and the pressure of the hydraulic oil is set to the low pressure side. , A signal is issued to the electromagnetic proportional flow valve 11, and the flow rate of the hydraulic oil is set to be small.
As a result, the movable platen 3 moves forward at a low pressure and at a low speed, and in the unlikely event that foreign matter is caught in the mating surfaces of the fixed mold 1 and the movable mold 4, the movement of the movable platen 3 is stopped,
An alarm is issued and the fixed mold 1 and the movable mold 4 are protected.

Further, the crosshead 8 of the toggle mechanism 7 advances and the movable platen 3 advances. At this time, the position data sequentially detected by the rotary encoder 24 is compared with the position data E15 read and stored and corrected at the time of setup, and when the detected position data becomes the position data E15, the following operation is performed. Done. Here, the above-mentioned position data DE is set to 0 when the crosshead 8 is most advanced, and is a positive value that sequentially increases when the crosshead 8 is retracted. Therefore, the position data E15 corrected by adding the coefficient α is It is larger than the position data DE, and immediately before the mating surfaces of the fixed mold 1 and the movable mold 4 contact each other, α (0.
The position data E15 is just before (02 mm).

When the position data detected by the rotary encoder 24 becomes the position data E15,
A signal is transmitted from the control device 16 to the electromagnetic proportional pressure valve 14, and the pressure of the hydraulic oil supplied to the mold clamping cylinder 9 is set to the high pressure side. Further, a signal is transmitted from the control device 16 to the electromagnetic proportional flow valve 11, and the flow rate of the hydraulic oil supplied to the mold clamping cylinder 9 is set to be large.

As a result, the hydraulic oil supplied to the mold clamping cylinder 9 has a high pressure and a high flow rate, and the crosshead 8 of the toggle mechanism 7 advanced by the mold clamping cylinder 9 is advanced at a high load and at a high speed. And the movable mold 4 attached to the movable platen 3 is fixed to the fixed platen 2
It is brought into contact with the high pressure and high load to perform high pressure mold clamping. In this way, the molten resin is injected from the heating cylinder (not shown) into the cavities in the fixed mold 1 and the movable mold 4 that have been clamped at a high pressure, and the injection process ends.

When the resin injected into the fixed mold 1 and the movable mold 4 is solidified, a signal is sent from the control device 16 to the electromagnetic switching valve 10 and switched to the side b in FIG. 1 to switch to the crosshead of the toggle mechanism 7. 8 is retracted to move the movable platen 3 away from the fixed platen 2 so that the fixed mold 1 and the movable mold 4 are separated from each other and the molded product is discharged to complete one cycle.

Incidentally, one lot of injection molding is carried out,
When the fixed switch and the movable mold are exchanged with those having different mold thicknesses for injection molding of the next lot, when the reset switch is pressed, the position data D stored in the memory is stored.
E and the position data E15 are cleared, and by doing so, the position corresponding to the newly attached fixed mold and movable mold can be obtained by performing the same procedure as the above-mentioned method. The data DE and the position data E15 are newly read and stored in the memory.

As described above, the position data DE and E15 of the rotary encoder 24 when the mating surfaces of the fixed mold 1 and the movable mold 4 come into contact with each other after retightening at the time of setup are read and stored, In the mold clamping step, the position of the crosshead 8 of the toggle mechanism 7 is sequentially detected by the rotary encoder 24, and the detected position data and the position data E15 obtained by adding the correction value α to the position data DE stored at the time of setup. When they match, the drive of the movable platen 3 is switched from the low pressure / low speed operating state to the high pressure / high speed operating state to perform the high pressure mold clamping.

Therefore, it suffices that the fixed mold 1 and the movable mold 4 are simply brought into contact with each other at the time of setup, and there is no need to adjust the operating position of the limit switch by moving the cam plate for each setup as in the conventional case. The setup work can be simplified.

Further, in the conventional adjustment by moving the cam plate, it was not possible to perform the position adjustment with high accuracy, and there was a problem in the above-mentioned operation. However, in this embodiment, the fixed mold 1 is set at the time of setup. The position of the crosshead 8 when the movable mold 4 and the movable die 4 contact each other is detected by the rotary encoder 24 and stored as position data DE, and the stored position data E1 is corrected.
5 is compared with the position data of the cross head 8 detected by the rotary encoder 24 in the normal mold clamping process, the changed position of the mold clamping force can be accurately controlled.

Moreover, since the crosshead 8 has a movement amount of 20 to 30 times the movement amount of the movable platen 3 due to the boosting characteristic of the toggle mechanism 7, the position of the crosshead 8 can be changed as in this embodiment. If the change point of the mold clamping force is detected by the rotary encoder 24, the resolution is 20 to 30 times higher than that when the position of the movable platen 3 is directly measured by the sensor, and the accuracy is high. The change point can be controlled with high accuracy without using an expensive sensor.

In this embodiment, the position data DE of the cross head 8 when the mating surfaces of the fixed mold 1 and the movable mold 4 come into contact with each other during the setup are corrected by the correction value α for correcting the thermal expansion. The position data E15 is obtained, and this position data E1
Since the operation of the mold clamping cylinder 9 is controlled based on 5, the fixed mold 1 and the movable mold 4 that have been cooled at the time of setup are used to actually inject the fixed mold 1 and the movable mold 4. Even if the mold 4 warms and expands in the mold thickness direction, the operating state of the mold clamping cylinder 9 can be reliably switched.

In this embodiment, the mold clamping cylinder 9 utilizing hydraulic pressure is used as the actuator for moving the crosshead 8 forward or backward, but an electric motor can be used as the actuator. In this case, an electric circuit that increases or decreases the current supplied to the electric motor is used as the actuator operation control unit that controls the operation of the electric motor.

[0055]

As described above, in the injection molding machine of the present invention, the fixed plate to which the fixed mold is attached and the movable mold are attached, and the movable plate is provided so as to be movable back and forth with respect to the fixed plate. Board, an end plate provided at the rear of the movable board, the end plate and the movable board are interconnected, and a crosshead is moved forward and backward with respect to the end plate to move the movable board to the end plate. A toggle mechanism for moving back and forth, an actuator for driving the crosshead forward and backward with respect to the end plate, and an actuator operation control means for controlling the mold clamping force between the movable mold and the fixed mold by the actuator,
Position detecting means for detecting a relative position of the cross head with respect to the end plate, and the movable plate is brought close to the fixed plate by reducing the mold clamping force by the actuator by the actuator operation control means.
After that, in the injection molding machine in which the mold clamping force by the actuator is largely changed by the actuator operation control means to close the movable platen to the fixed platen and the mold is clamped, the toggle mechanism is extended at the time of setup. In this state, the end plate is moved forward to bring the movable mold into contact with the fixed mold, and the end plate is relatively moved with respect to the fixed platen to be retightened, and the actuator is operated to move the crosshead. When the movable platen is moved forward, the movable mold and the fixed mold are brought into contact with each other.
As a result, the mold clamping force of the actuator is small
In the stores the read write memory means reads the position data indicating the position of the cross head detected by the position detecting means, conventional clamping step when it detects that a value above, actuating the actuator Based on position data indicating the position of the cross head detected by the position detecting unit when the cross head is moved forward and the movable mold is moved forward, and position data stored in the read storage unit. seeking changes in the clamping force of the actuator, since a control means to control the actuator operation control means so as to increase the clamping force of the movable die by the actuator on the basis of this change, The position of the change point that increases the mold clamping force of the actuator that drives the movable plate can be easily and accurately adjusted.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram showing an injection molding machine according to an embodiment of the present invention.

FIG. 2 is a side view showing the vicinity of the crosshead of the injection molding machine according to the embodiment of the present invention.

FIG. 3 is a plan view showing the vicinity of a cross head of the injection molding machine according to the embodiment of the present invention.

FIG. 4 is a flowchart showing control of the injection molding machine according to the embodiment of the present invention.

FIG. 5 is an explanatory view showing a case where setup work is performed using the injection molding machine according to the embodiment of the present invention.

[Explanation of symbols]

 1 Fixed mold 2 Fixed plate 3 Movable plate 4 Movable plate 5 Tie bar 6 End plate 7 Toggle mechanism 8 Crosshead 9 Mold clamping cylinder (actuator) 10 Electromagnetic switching valve (actuator operation control means) 11 Electromagnetic proportional flow valve (actuator operation) Control means) 13 Main relief valve (actuator operation control means) 14 Electromagnetic proportional pressure valve (actuator operation control means) 16 Control device (control means) 24 Rotary encoder (position detection means) S5 Read storage means

Claims (1)

[Claims] 1. A fixed plate to which a fixed mold is attached, a movable plate to which a movable mold is attached and which is movable forward and backward with respect to the fixed plate, and an end plate provided to the rear of the movable plate. A toggle mechanism that connects the end plate and the movable plate to each other and moves a crosshead forward and backward with respect to the end plate to move the movable plate forward and backward with respect to the end plate; and the crosshead with the end plate. An actuator that is driven back and forth with respect to the actuator, and actuator operation control means that controls the mold clamping force between the movable mold and the fixed mold by the actuator,
Position detecting means for detecting a relative position of the cross head with respect to the end plate, and the movable plate is brought close to the fixed plate by reducing the mold clamping force by the actuator by the actuator operation control means.
Thereafter, in the injection molding machine in which the actuator operation control means largely changes the mold clamping force by the actuator to bring the movable platen closer to the fixed platen to perform mold clamping, the toggle mechanism is extended at the time of setup. In this state, the end plate is moved forward to bring the movable mold into contact with the fixed mold, and the end plate is relatively moved with respect to the fixed platen to be retightened, and the actuator is operated to move the crosshead. when the advancing were advancing the movable platen, the stationary die and the child contact with the movable mold
The mold clamping force by the actuator is less than the above value.
Stored in the read write memory means reads the position data indicating a position of the crosshead detected by said position detecting means when it detects that a above, in conventional mold clamping process, actuates the actuator Based on position data indicating the position of the cross head detected by the position detection unit when the cross head is moved forward and the movable mold is moved forward, and position data stored in the read storage unit. A control hand for obtaining a change point of the mold clamping force of the actuator and controlling the actuator operation control means so as to increase the mold clamping force of the movable mold by the actuator based on the change point.
An injection molding machine characterized by having steps .