JP3638381B2 - Mold clamping control method for injection molding machine - Google Patents

Description

[0001]
BACKGROUND 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 control method in a mold clamping device configured to open and close a mold at a high speed via a mold opening / closing cylinder during the mold clamping process.
[0002]
[Prior art]
In general, in a composite mold clamping apparatus of an injection molding machine as shown in FIG. 1, a moving die plate 12 holding a moving mold 10 is first opened and closed with respect to a fixed die plate 16 holding a fixed mold 14. By operating the valve 20 to the b position and supplying the pressure oil from the hydraulic source 18 from the supply hydraulic line 18a to the mold opening / closing cylinder 24 (cylinder 24a, piston 24b) via the mold closing hydraulic line 22a. Move in the direction of the arrow to close the mold. Thereafter, the mold clamping valve 30 is operated to its position a to supply pressure oil from the hydraulic power source 18 through the mold clamping hydraulic line 32 from the supply hydraulic line 18b to the mold clamping cylinder 34 (cylinder 34a, ram 34b). The mold is clamped by supplying to
[0003]
In FIG. 1, reference numeral 12 a indicates a limit switch that is provided on the moving path of the moving die plate 12 and confirms the mold closing limit. Reference numeral 26 denotes a pressure switch that is provided on the mold closing hydraulic line 22a of the mold opening / closing valve 20 and confirms an increase in the mold closing pressure. Further, reference numeral 28 denotes a relief valve which is also provided on the mold opening hydraulic line 22b and releases the excessive pressure. Reference numeral 36 denotes a pressure switch that is provided on the mold clamping hydraulic line 32 of the mold clamping valve 30 and that confirms an increase in mold clamping pressure.
[0004]
In the above apparatus, the movable mold 10 is configured as a spring-loaded mold having a repulsive spring 10a. Further, 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 engaging screw portion 40a. By supplying the pressure oil from the supply hydraulic line 18b through the operation valve 42 and the operation cylinder 44, it is configured to be engaged with and detached from the engagement screw portion 40a.
[0005]
Therefore, according to such a configuration, it is possible to automatically and efficiently perform mold clamping of this type of injection molding machine.
[0006]
[Problems to be solved by the invention]
However, the mold clamping control method of the conventional injection molding machine still has the following problems.
[0007]
That is, FIG. 3 is a graph display of the above-described mold clamping control in terms of operation time for each operation process (1 to 8). Therefore, although it overlaps with the above-mentioned, when it demonstrates easily again, when the type | mold opening-and-closing valve 20 is operated by b position (process 1), the movement die plate 10 will start a movement (process 8). When the mold closing limit is reached, the limit switch 12a is activated, the mold closing pressure 22a is increased (steps 3 and 6), and when the mold closing pressure 22a reaches a predetermined pressure, the mold closing pressure switch 26 is reached. Is operated, 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 is turned on. Operate. That is, mold clamping is performed (steps 7 and 5).
[0008]
However, in this graph, that is, in the mold clamping control, the mold closing limit switch 12a and the mold closing pressure switch 26 are as shown in the figure for a specific time ΔT over the boosting of the operating time and the mold clamping. That function was interrupted. That is, during this specific time ΔT, as shown in the graph, the mold closing pressure 22a temporarily decreases when the mold clamping valve 30 is operated (the mold clamping pressure 32 is increased).
[0009]
This is because the pressures 32 and 22a communicate with each other through the hydraulic lines 18a and 18b, so that the mold closing pressures of the molds 10 and 12 are not maintained due to the pressure difference between the hydraulic lines. In the case of a mold containing 10a, the repulsive force causes the moving die plate 10 to move backward, turning off the limit switch 12a, and then causing an unstable operation such as stopping the operation or moving forward again. It was. In this case, in the present apparatus having the tie bar 40, it is obvious that the threaded portion 40a and the half nut 46 are not engaged.
[0010]
Therefore, an object of the present invention is to provide a mold clamping control method for an injection molding machine that can clamp a mold clamping device, in particular, even when the mold is a spring-loaded mold, stably and reliably. There is.
[0011]
[Means for Solving the Problems]
In order to achieve the above object, a mold clamping control method for an injection molding machine according to the present invention includes a mold opening / closing valve and a movable die plate for holding a movable mold with respect to a fixed die plate for holding a fixed mold. In a mold clamping control method of an injection molding machine that moves through a mold opening / closing cylinder and closes the mold, and then performs mold clamping through a mold clamping valve and a mold clamping cylinder,
The moving die plate is provided with a limit switch for confirming the mold closing limit on its moving path, the mold opening / closing valve is provided with a pressure switch for confirming the rise of the mold closing pressure on the mold closing hydraulic line, and the mold clamping valve is A pressure switch is provided on the mold clamping hydraulic line to confirm the rise in mold clamping pressure, the mold opening / closing valve is operated to start mold closing, and the mold closing limit is confirmed via the limit switch on the moving die plate. Check the mold closing pressure rise via the pressure switch of the closing hydraulic line, and operate the mold opening / closing valve so that this increased mold closing pressure is maintained as it is, then operate the mold clamping valve to switch the pressure switch It is characterized by operating to confirm the increase in mold clamping pressure.
[0012]
In this case, the mold clamping control method of the present invention can be performed stably and reliably even when the moving and / or fixed mold is provided with a repulsion spring.
[0013]
In the mold clamping control method according to the present invention, the mold clamping operation is performed in such a manner that after the mold closing pressure of the mold opening / closing valve for closing the movable die plate rises to a predetermined pressure, the increased predetermined pressure is maintained as it is. This is accomplished by actuating the valve.
[0014]
Therefore, according to the present invention, when the mold clamping valve is operated, even if the mold clamping pressure is lower than the rising mold closing pressure, the mold closing pressure is temporarily reduced as in the prior art. Therefore, the mold clamping operation can be performed stably and reliably.
[0015]
【Example】
Next, embodiments of a mold clamping control method for an injection molding machine according to the present invention will be described in detail with reference to the accompanying drawings.
[0016]
First, in the present invention, the apparatus for carrying out the mold clamping control method and the operation process thereof are basically the same as the conventional apparatus (see FIG. 1) and the process (see FIG. 3). Accordingly, the following description of the mold clamping control method of the present invention will be made with reference to FIG. 1 and with reference to FIG. 2 corresponding to FIG.
[0017]
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 in the conventional case (FIG. 3). When the 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 is activated and the mold closing pressure 22a is increased (steps 3 and 6). When the mold closing pressure 22a reaches a predetermined pressure, the mold closing pressure switch 26 is actuated and the mold clamping valve 30 is operated to the position a to increase the mold clamping pressure 32 (steps 4 and 2). . When the mold clamping pressure 32 reaches a predetermined pressure, the mold clamping pressure switch 36 is activated. That is, mold clamping is performed (steps 7 and 5).
[0018]
However, in the present invention, according to the above 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 by the pressure. While confirming that the mold closing pressure (22a) has risen via the switch 26 and the increased mold closing pressure (22a) is maintained (that is, the mold opening / closing valve 20 is turned off), The clamping valve 30 is actuated and is operated via its pressure switch 36 to confirm the rise in mold clamping pressure (32).
[0019]
That is, to explain in relation to the process shown in FIG. 2, in the mold clamping operation, the mold opening / closing valve 20 is operated (process 1), and an increase in the mold closing pressure 22a is confirmed by the pressure switch 26 (process). 6) When the increased mold closing pressure 22a is maintained as it is (step 6), the mold clamping valve 30 is operated (step 2), and the rise of the mold clamping pressure 32 is confirmed by the pressure switch 36. To obtain (step 7).
[0020]
As described above, in the present invention, the mold opening / closing valve is configured such that after the mold closing pressure of the mold opening / closing valve for closing the movable die plate rises to a predetermined pressure, the increased predetermined pressure is maintained as it is. And then the mold clamping valve is activated. As a result, even if the mold clamping pressure is lower than the rising mold closing pressure when the mold clamping valve is operated, the mold closing pressure is temporarily changed as in the prior art, that is, during the specific time ΔT. In the next process, the half nut 46 is supplied with pressure oil from the supply hydraulic line 18b via the operation valve 42 and the operation cylinder 44, so that the engagement thread portion is not lowered. 40a can be engaged and disengaged.
[0021]
Therefore, according to the present invention, this type of combined mold clamping control can be achieved stably and reliably even when the mold is spring-loaded.
[0022]
The preferred embodiments of the present invention have been described above, but the present invention is not limited to the above-described embodiments, 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 in the same manner for direct pressure type mold clamping control having a so-called mold opening / closing cylinder that does not have a tie bar engaging thread portion in the apparatus (FIG. 1). Can do.
[0023]
【The invention's effect】
As described above, the mold clamping control method for an injection molding machine according to the present invention can be summarized as follows: a movable die plate (moving mold) is fixed to a fixed die plate (fixed mold) via a mold opening / closing valve. In mold clamping control of a mold clamping device that performs mold clamping via a mold clamping valve after high-speed mold closing, the mold clamping control is performed after the mold closing pressure of the mold opening / closing valve has increased to a predetermined pressure. The mold clamping valve is operated in a state where the mold is held as it is, so that even if the mold clamping pressure is lower than the rising mold closing pressure when the mold clamping valve is operated, Even with a spring, mold clamping control can be achieved stably and reliably.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of a general apparatus for performing a mold clamping control method of an injection molding machine.
FIG. 2 is a graph showing each operation time for each operation process of an embodiment of the mold clamping control method according to the present invention in the apparatus shown in FIG. 1;
FIG. 3 is a graph showing each operation time for each operation process of the conventional mold clamping control method in the apparatus shown in FIG. 1;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Moving mold 10a Spring 12 Moving die plate 12a Limit switch 14 Fixed mold 16 Fixed die plate 18 Hydraulic 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 pressure switch 30 Mold clamping valve 32 Mold clamping hydraulic line (Clamping pressure)
34 Clamping cylinder 36 Clamping pressure rise confirmation pressure switch 40 Tie bar 40a Engagement screw part 42 Operation valve 44 Operation cylinder 46 Half nut

Claims (2)

The movable die plate holding the moving mold is moved with respect to the fixed die plate holding the fixed mold through the mold opening / closing valve and the mold opening / closing cylinder, and then the mold is closed. In a mold clamping control method of an injection molding machine that performs mold clamping,
The moving die plate is provided with a limit switch for confirming the mold closing limit on its moving path, the mold opening / closing valve is provided with a pressure switch for confirming the rise of the mold closing pressure on the mold closing hydraulic line, and the mold clamping valve is A pressure switch is provided on the mold clamping hydraulic line to confirm the rise in mold clamping pressure, the mold opening / closing valve is operated to start mold closing, and the mold closing limit is confirmed via the limit switch on the moving die plate. Check the mold closing pressure rise via the pressure switch of the closing hydraulic line, and operate the mold opening / closing valve so that this increased mold closing pressure is maintained as it is, then operate the mold clamping valve to switch the pressure switch A mold clamping control method for an injection molding machine, wherein the mold clamping pressure rise is confirmed through the operation. 2. The mold clamping control method for an injection molding machine according to claim 1, wherein the moving and / or fixed mold is provided with a repulsion spring.

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