JPH1029230A - Mold clamping control method of injection molding machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mold clamping method of an injection molding machine capable of safely and certainly clamping a mold clamping apparatus even if the mold thereof is especially a spring-containing mold. SOLUTION: In the mold clamping control of a mold clamping apparatus wherein a moving die plate 12 holding a movable mold 10 is moved with respect to a fixed die plate 16 holding a fixed mold 14 through a mold opening and closing valve 20 and a mold opening and closing cylinder 24 to clamp the molds and mold clamping is performed by a mold clamping valve 30 and a mold clamping cylinder 34, the mold clamping control is operated so that a moving die plate 12 confirms a mold clamping limit through its limit switch 12a and the mold opening and closing valve 20 confirms the rising of mold closing pressure 22a through a pressure switch 26 and the raised mold closing pressure 22a is held as it is, that is, the mold clamping valve 30 is operated in such a state that the mold opening and closing valve 20 is turned OFF and the rising of mold clamping pressure 32 is confirmed through the pressure switch 36 thereof.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold clamping control method for an injection molding machine, and more particularly, to a mold clamping apparatus in which a mold is opened and closed at a high speed via a mold opening / closing cylinder in the mold clamping process. It relates to a control method.

[0002]

2. Description of the Related Art Generally, in a composite mold clamping apparatus of an injection molding machine as shown in FIG. 1, a movable die plate 12 for holding a movable mold 10 is fixed to a fixed die plate 16 for holding a fixed mold 14. First, the mold opening / closing valve 20 is operated to the position b to supply the pressure oil from the hydraulic pressure source 18 to the mold opening / closing cylinder 24 (cylinder 24a, piston 24b) from the supply hydraulic line 18a via the mold closing hydraulic line 22a. As a result, the mold is moved in the direction shown by the arrow to close the mold. Then, the mold clamping valve 30 is operated to the position a to supply the pressure oil from the hydraulic pressure source 18 to the supply hydraulic line 18b.
From the mold clamping cylinder 34 via the mold clamping hydraulic line 32.
(Cylinder 34a, ram 34b) to perform mold clamping.

In FIG. 1, reference numeral 12a is
A limit switch is provided on the movement path of the movable die plate 12 and checks the mold closing limit. Reference numeral 26 denotes a pressure switch provided on the mold closing hydraulic line 22a of the mold opening / closing valve 20 for confirming an increase in the mold closing pressure. Further, reference numeral 28 indicates the mold opening hydraulic line 2
2b shows a relief valve provided on 2b for releasing its excess pressure. Reference numeral 36 denotes a pressure switch provided on the mold clamping hydraulic line 32 of the mold clamping valve 30 for confirming an increase in the mold clamping pressure.

[0004] In the above apparatus, the moving mold 10
Is configured as a spring-loaded mold having a rebound spring 10a. A tie bar 40 is mounted between the movable die plate 12 and the fixed die plate 16, and a half nut 46 is disposed at a position facing the engagement screw portion 40 a.
Supplies pressure oil from the supply hydraulic line 18b to the operation valve 4
It is configured to be engaged with and disengaged from the engagement screw portion 40a by supplying it through the second cylinder 2 and the operation cylinder 44.

Therefore, according to such a configuration, it is possible to automatically and efficiently perform mold clamping of this type of injection molding machine.

[0006]

However, the above-described conventional mold clamping control method for an injection molding machine still has the following disadvantages.

That is, FIG. 3 shows the above-described mold clamping control.
The operation time (1-8) is graphed in terms of operating time for each operation step (1-8). Therefore, although it is the same as the above, but briefly described again, the graph shows the mold opening / closing valve 20.
Is moved to the position b (step 1), the movable die plate 10 starts moving (step 8). Then, when the mold closing limit is reached, the limit switch 12a operates, and
When the mold closing pressure 22a increases (steps 3 and 6), and the mold closing pressure 22a reaches a predetermined pressure, the mold closing pressure switch 2
6, the mold clamping valve 30 is operated to the position a, the mold clamping pressure 32 rises (steps 4 and 2), and when the mold clamping pressure 32 reaches a predetermined pressure, the mold clamping pressure switch 36 Operates. That is, mold clamping is performed (Steps 7, 5).

However, in this graph, that is, in the mold clamping control, the mold closing limit switch 12 is closed during the specific time ΔT over which the operating time is increased and the mold is clamped.
a and the mold closing pressure switch 26, as shown, could have their functions interrupted. That is,
During the specific time ΔT, the operation of the mold clamping valve 30 (increase of the mold clamping pressure 32) as shown in the graph.
At this time, the mold closing pressure 22a temporarily decreases.

Since the pressures 32 and 22a communicate with each other through the hydraulic lines 18a and 18b,
Due to the pressure difference between the hydraulic lines, the mold closing pressures of both the molds 10 and 12 are not maintained. Particularly in the case of a mold with a spring 10a, the movable die plate 10 retreats reversely due to the repulsive force and the limit switch 12a. , And then unstable operation such as stopping its operation or moving forward again. In this case, in the present device having the tie bar 40, the screw portion 40a and the half nut 4
It is clear that no engagement with 6 is performed.

Accordingly, an object of the present invention is to provide a mold clamping control method for an injection molding machine capable of stably and reliably clamping a mold clamping device, particularly even when the mold is a spring-loaded mold. Is to provide.

[0011]

In order to achieve the above object, a mold clamping control method for an injection molding machine according to the present invention comprises a moving die plate holding a moving die, a fixed die holding a fixed die. In the mold clamping control method of the injection molding machine, which moves the mold via the mold opening / closing valve and the mold opening / closing cylinder and closes the mold after closing the mold via the mold closing valve and the mold closing cylinder, the moving die plate is A limit switch for checking the mold closing limit is provided on the moving path, a mold opening / closing valve is provided with a pressure switch for checking the rise of the mold closing pressure on the mold closing hydraulic line, and a mold closing valve is provided for the mold closing hydraulic line. A pressure switch to check the rise of the mold clamping pressure is provided on the top, the mold opening and closing valve is activated to start mold closing, and the mold closing limit is confirmed via the limit switch of the movable die plate.
The mold closing pressure rise is confirmed via the pressure switch of the mold closing hydraulic line, and the mold opening / closing valve is operated so that the increased mold closing pressure is maintained as it is, and then the mold closing valve is operated to operate the pressure switch. The operation is performed so as to confirm an increase in the mold clamping pressure via the.

[0012] In this case, the mold clamping control method of the present invention includes:
In particular, even when the moving and / or fixed mold is provided with a rebound spring, it can be stably and reliably performed.

In the mold clamping control method of the present invention, the mold clamping operation is performed in a state where the mold closing pressure of the mold opening / closing valve for mold closing the movable die plate rises to a predetermined pressure, and this rising predetermined pressure is maintained as it is. , By actuating the clamping valve.

Therefore, according to the present invention, even when the mold clamping pressure is lower than the increasing mold closing pressure during the operation of the mold closing valve, the mold closing pressure is temporarily reduced as in the prior art. Therefore, the mold clamping operation can be performed stably and reliably.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of a method for controlling clamping of an injection molding machine according to the present invention will be described in detail with reference to the accompanying drawings.

First, in the present invention, an apparatus for implementing the mold clamping control method and its operation steps are basically the same as the conventional apparatus (see FIG. 1) and steps (see FIG. 3). . Therefore, the following description of the mold clamping control method of the present invention will be made with reference to FIG. 1 and FIG. 2 corresponding to FIG.

That is, in FIG. 2 in which the operation steps (1 to 8) are graphically displayed in terms of operation time, the basic steps of the mold clamping control method of the present invention are the same as those in the conventional case (FIG. 3).
Similarly, when the mold opening / closing valve 20 is operated to the position b (step 1), the movable die plate 10 starts moving (step 8). When the mold closing limit is reached, the mold closing limit switch 12a operates and the mold closing pressure 22a.
Rise (Steps 3 and 6). And this mold closing pressure 22
When a reaches a predetermined pressure, the mold closing pressure switch 26 is operated, and the mold closing valve 30 is operated to the position a, so that the mold closing pressure 32 is increased (steps 4 and 2). When the mold clamping pressure 32 reaches a predetermined pressure, the mold clamping pressure switch 3
6 is activated. That is, mold clamping is performed (Step 7,
5).

However, in the present invention, according to the configuration (step), the mold clamping is performed by the movable die plate 12 confirming the mold closing via the mold closing limit switch 12a, and the mold opening / closing valve 20. Is the pressure switch 26
The mold closing pressure (22a) is confirmed to rise through the mold closing pressure (22a), and while the increased mold closing pressure (22a) is maintained (that is, the mold opening / closing valve 20 is turned off), the mold closing valve is closed. 30 is activated and operated via its pressure switch 36 so as to confirm that the mold clamping pressure (32) has risen.

In other words, the mold closing operation will be described with reference to the above-described step shown in FIG. 2 (step 1).
6 (Step 6), the increased mold closing pressure 2
In a state where 2a is held as it is (step 6), the mold clamping valve 30 is operated (step 2), and operation is performed so that the increase of the mold clamping pressure 32 can be confirmed by the pressure switch 36 (step 7). .

As described above, in the present invention, after the mold closing pressure of the mold opening / closing valve for closing the movable die plate has risen to the predetermined pressure, the mold clamping operation maintains the raised predetermined pressure as it is. This is achieved by activating the mold opening / closing valve and then activating the mold closing valve. As a result, even when the mold closing pressure is lower than the increasing mold closing pressure during the operation of the mold closing valve, the mold closing pressure is temporarily reduced as in the related art, that is, during the specific time ΔT. In the next step, the half nut 46 does not decrease as much as the mold clamping pressure.
By supplying the pressure oil from the supply hydraulic line 18b via the operation valve 42 and the operation cylinder 44, the engagement and disengagement with the engagement screw portion 40a can be performed.

Therefore, according to the present invention, this type of combined mold clamping control can be stably and reliably achieved even if the mold is spring-loaded.

Although the preferred embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment, and many design changes can be made without departing from the spirit of the present invention. For example, the mold clamping control method of the present invention operates substantially the same in the above-described apparatus (FIG. 1) in a direct pressure mold clamping control having a so-called mold opening / closing cylinder having no tie bar engaging screw portion. Can be.

[0023]

As described above, the mold clamping control method for an injection molding machine according to the present invention can be summarized as follows: a moving die plate (moving die) is fixed to a fixed die plate (fixed die). After closing the mold at a high speed via the opening / closing valve, in the mold clamping control of the mold clamping device for clamping the mold via the mold clamping valve, the mold clamping control is performed after the mold closing pressure of the mold opening / closing valve rises to a predetermined pressure. The configuration in which the mold clamping valve is operated in a state where the rising predetermined pressure is held as it is, even if the mold clamping pressure is lower than the rising mold closing pressure when the mold clamping valve is operated, In particular, even if the mold contains a spring, mold clamping control can be stably and reliably achieved.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a general device that implements a mold clamping control method of an injection molding machine.

FIG. 2 is a graph showing operation times of the apparatus shown in FIG. 1 for each operation step of the embodiment of the mold clamping control method according to the present invention.

FIG. 3 is a graph showing operation times of the apparatus shown in FIG. 1 for respective operation steps of a conventional mold clamping control method.

[Description of Signs] 10 Moving mold 10a Spring 12 Moving die plate 12a Limit switch 14 Fixed mold 16 Fixed die plate 18 Hydraulic power source 18a, 18b Supply hydraulic line 20 Mold opening / closing valve 22a Mold closing hydraulic line (mold closing pressure) 24 Mold opening / closing cylinder 26 Mold closing pressure rise confirmation pressure switch 30 Mold clamping valve 32 Mold clamping hydraulic line (clamping pressure) 34 Mold clamping cylinder 36 Mold clamping pressure rise confirmation pressure switch 40 Tie bar 40a Engagement screw 42 Operation valve 44 Operation cylinder 46 Half nut

Claims (2)

[Claims] A moving die plate holding a moving mold is moved relative to a fixed die plate holding a fixed mold via a mold opening / closing valve and a mold opening / closing cylinder to close the mold. In a mold clamping control method for an injection molding machine that performs mold clamping via a mold clamping cylinder, a moving die plate is provided with a limit switch for confirming a mold closing limit on a moving path thereof, and a mold opening / closing valve is provided on the mold closing hydraulic line. A pressure switch for checking the rise of the mold closing pressure is provided in the mold closing valve, and a pressure switch for checking the rise of the mold closing pressure is provided on the mold closing hydraulic line. Start, confirm the mold closing limit via the limit switch of the moving die plate, confirm the mold closing pressure rise via the pressure switch of the mold closing hydraulic line, and keep this increased mold closing pressure as it is Mold opening and closing valve to actuate the mold clamping control method for an injection molding machine, characterized in that the manipulated to confirm the clamping pressure rise through the pressure switch actuates the subsequent clamping valve so. 2. The mold clamping control method for an injection molding machine according to claim 1, wherein the movable and / or fixed mold is provided with a repulsion spring.