JPS61279523A - Controlling device for opening and closing of mold - Google Patents

Abstract

PURPOSE:To enable to automatically exchange a mold by a method wherein an absolute position system, which employs the position of an origin signal transmitter located at a certain fixed distance from a stationary die plate as the reference point, is used for controlling the opening and closing of the mold when the exchange of molds is intended. CONSTITUTION:In order to exchange a mold at the completion of a molding by the mold 13 in use, when the molding is brought to an end by closely contacting the mold 13, a mold exchange controlling circuit 19 issues the instruction to position the mold 13 at the position that the right side surface of a moving die plate 12 stands apart from the left side surface of a stationary die plate 11 by the distance of the thickness of the mold opened by springs plus some allowance. The positional control by a counter 18 is done by employing the position of an origin signal transmitter located at a certain fixed distance from the left side surface of the stationary die plate 11 as the reference point. Because the origin signal transmitter 22 is cleared by being pushed with a staff 16 and, after being cleared, keeps on counting, the leftward movement of the moving die plate 12 is counted by the counter 18. When the moving die plate 12 reaches the instructed position, the mold exchange controlling circuit 19 is brought into actuation through the counter 18 so as to stop the moving die plate 12 at said position. Consequently, the mold 13 is taken out without trouble and a new mold is taken in.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical field to which the invention pertains] The present invention relates to a mold opening/closing control device for an injection molding machine or a die casting machine (hereinafter referred to as a molding machine).

[Prior art]

Conventional mold opening/closing control devices for molding machines can be roughly divided into two types: one uses potentiometers, absolute encoders, etc. to detect the position of a moving die plate to which a moving die is fixed as an absolute position, and the other uses incremental encoders, etc. to detect the mold closing limit position. There are two types of detection methods: one detects the position relative to the origin, but since the mold of the molding machine expands due to the heat it receives from the molten resin and metal during molding, the above two methods are as follows: There was a drawback. In the absolute position method, it is necessary to change the set position according to the thermal expansion of the mold, and in particular, the mold closing position requires accurate position setting, including the mold protection function, and changing the set position is time-consuming. Kari lowered productivity.

On the other hand, in the relative position method based on the mold closing limit, zero is cleared at the mold closing limit of every cycle, so there is no effect of thermal expansion, and although this method is usually used, there are problems when replacing the mold. may occur. In other words, when replacing the mold, first take out the mold currently in use, but at this time move the movable die plate to a position slightly wider than the mold thickness (thickness when closed), for example, to a position with a margin of 10 mm. . However, in the case of a spring-loaded mold, there are two values for the mold thickness, one when the spring is closed and one when the spring is open.If these values are set to 300m and 330m, it is natural that there will be a gap when replacing the mold. This must be done based on the value of . However, in the relative position method, the position is controlled based on the mold closing limit, so if the desired closing limit, that is, 300cm when the spring is closed, is used as a reference, and an allowance of 10m is added to this, the movement is 310m. , it is impossible to transport the mold without reaching the value of 330 m when opened by the spring. Therefore, automatic mold replacement is impossible and manual operation is required, which results in high human costs and requires a long time, which also increases costs.

[Purpose of the invention]

The present invention eliminates these drawbacks, and its purpose is to:
When replacing molds, the absolute positioning system enables automatic mold replacement for regular molds without springs as well as molds with springs.

It is an object of the present invention to provide a mold opening/closing control device that can cope with changes in mold thickness due to thermal expansion during a molding cycle using a relative position method.

[Key points of the invention]

The mold opening/closing control device of the present invention detects the position of a movable die plate that moves opposite to a fixed die plate using a scale and a detection head to control the position of the movable die plate. In order to replace type 5 in the machine, the position of the movable die plate is determined by counting the output signal of the detection head using the absolute position method based on the position t, yt of the origin signal transmitter placed at a certain distance from the fixed die rate. and a second counter that counts the output signal of the detection head using a relative position method based on the mold closing limit position for opening and closing the movable die plate.

[Embodiments of the invention]

Figure R (showing one embodiment of the present invention) will be explained below.

A mold 13 consisting of a fixed mold 13A and a movable mold 13B is fixed to the facing surface of the fixed die plate 11 and the movable die plate 12, and the fixed mold 13A is always fixed to the left side in the figure by a spring (not shown). A separation mold 13C is attached which is pressed by. The tip of a piston 15 of a mold clamping cylinder 14 is fixed to the movable die plate 12, and a scale 16 is attached to the mold clamping cylinder 14 side and in the direction of movement thereof.A detection head 17 for reading the scale 16 faces the scale 16. ing.

The output signal of the detection head 17 is divided into two parts, the first of which is
It is sent to the mold exchange control circuit 19 via the counter 18, and sent to the mold opening/closing control circuit 21 via the second Fi second counter 20 as an output signal.

The first counter 18 is activated when the origin signal transmitter 22 placed at a certain distance from the left side surface of the fixed die plate 11 is pressed by the scale 16.

Clear the count up to now and start counting with the above constant distance value as the origin. The second counter 20 is configured such that when the oil chamber 14A on the mold clamping side of the mold clamping cylinder 14 reaches the mold clamping pressure, the pressure sensor 23 detects this, the count is cleared by the signal, and the count is continued b. Note 2
4 is an injection mechanism.

Next, the operation of the embodiment described above will be explained. The figure shows fixed mold 1
3A, the movable mold 13B, and the separation mold 13C are shown in a state in which they are clamped by a mold clamping cylinder 14 or the like and in close contact with each other, and in this state, molten resin (not shown) is injected from the injection mechanism 24. When the molten resin is cooled and solidified, the mold opening/closing control circuit 21 moves the movable die plate 12 backward (leftward) to open the mold. At this time, the second counter 20 is cleared by the previous mold clamping, and since this is a relative position method that uses that position as the origin, even if the mold 13 is thermally expanded, it can be changed from high-speed retraction to low-speed retraction at the corresponding position. The moving position of the moving die plate 12 is controlled to switch and stop.

It is assumed that when molding with the currently used mold 13 is completed and the mold is replaced, the mold 13 is brought into close contact as shown in the figure for the final molding, and the molding is completed. Here, the mold exchange control circuit 19 moves the movable die plate 1 at a distance equal to the mold thickness when the mold 13 is opened by the spring (330 m in the above explanation) plus a slight margin (the same <10 pieces).
2 issues a command to position from the left side of the fixed die rate 11. The position control by the first counter 18 is an absolute position method based on the position of the origin signal transmitter 22 placed at a certain distance from the left side surface of the fixed die plate 11, and the origin signal transmitter 22 is pressed by 16. It is cleared when the movable die plate 12 moves to the left, and continues to count. Therefore, when the movable die plate 12 moves to the left, it is counted by the first counter 18, and when the above-mentioned command position is reached, the mold exchange control circuit 19 is activated via the first counter 18. The moving die plate 12 stops at that position. Therefore, the mold 13 can be taken out without any problem, and then a new mold can be brought in and molding can be continued again.

In addition. It is convenient to back up the power supply of the first counter 18 with a battery because the first counter 18 will remember the count value when the AC power is turned on again after the AC power is turned off due to a power outage or the molding machine is stopped. It is.

〔Effect of the invention〕

As explained above, the mold opening/closing control device of the present invention employs an absolute position method that uses the position of the origin signal transmitter placed at a certain distance from the fixed die plate as a reference when changing molds for mold opening/closing control, which was previously impossible. It is now possible to automatically replace existing molds. Further, when opening and closing the movable die plate for molding, a relative position method is used based on the mold closing limit, so thermal expansion is absorbed and has no effect.

[Brief explanation of the drawing]

The figure is a partially sectional view of a mechanism showing an embodiment of the present invention. 11... Fixed die plate, 12... Moving die plate, 13... Mold, 16... Scale, 17...
・Detection head, 18...8g1 counter, 20...
Second counter, 22... Origin signal transmitter

Claims (1)

[Scope of Claims] 1) In a molding machine such as an injection molding machine, the position of a movable die plate that moves opposite to a fixed die plate is detected by a scale and a detection head to control the position of the movable die plate, A first counter that counts the output signal of the detection head using an absolute position method in which the position of the movable die plate is set at a certain distance from the fixed die plate for mold exchange using an absolute position method. and a second counter which uses the output signal of the detection head as a counter using a relative position method in which the position of the movable die plate is based on the mold closing limit position for opening and closing the movable die plate. 2) The mold opening/closing control device according to claim 1, wherein the first counter has a battery backup function as a power source.