JP2513236Y2 - Control device for mold clamping device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a mold clamping device control device applied to a mold clamping device of an injection molding machine.

(Prior Art) FIG. 3 shows an example of a conventional direct pressure type mold clamping device. Here, a description will be given from a mold closing operation in which the mold is opened to a mold closing operation to a pressure increasing operation in which the mold is compressed. In the figure, a core side mold 6 is attached to the movable platen 2, and the movable platen 2 is operated by hydraulic pressure of a clamp ram 5,
It is designed to move.

First, the mold closing operation will be described. (1) Pressure oil is supplied from the hydraulic pressure source 11 to the oil chamber C, and the prefill valve 4 is at the backward limit (upper half of FIG. 3).

(2) Next, pressure oil is supplied to the oil chamber B from the hydraulic source 12 via the booster ram 7, so that the clamp ram 5 and the movable platen are moved.
2. The core side mold 6 moves to the right. 21 is a limit switch (LS1), which is a signal of mold closing,
It moves at a high speed from the position of the limit switch 21 shown to the position of the limit switch 22 (LS2). When the limit switch 22 is detected, the proportional flow rate valve 15 reduces the supply flow rate to reduce the mold closing speed.

Next, the boosting operation will be described. (1) The limit switch 23 (LS18) is set at a position slightly before the core side die 6 and the cavity side die 6a are in close contact with each other.

(2) When the limit switch 23 is detected, the SOL-PR of the solenoid valve 14 is turned on, the oil chamber C is released to the tank, and the booster ram 7 receives a large amount of high pressure oil from the hydraulic pressure source 12 and the proportional flow valve 15 And the prefill valve 4 is advanced (lower half of the figure).

(3) The pressure oil supplied to the booster ram 7 is connected to the oil chamber A by the advance of the prefill valve 4, and the oil chamber A
Since the communication with the tank is cut off, the high pressure oil is introduced into the oil chamber A and the pressure increasing operation is performed.

Now, after detecting the limit switch 23 (LS18),
In the process of shifting to the boosting operation, a certain time delay is provided by a timer in a control device (not shown) as shown in FIG. This is done to prevent the movable platen 2 from moving forward at high speed and damaging the mold when the limit switch 23 (LS18) is roughly set and the prefill valve 4 is moved with high pressure and large capacity. ing. The timer is generally
It is set to 0.2 to 0.3 seconds.

(Problems to be Solved by the Invention) In the conventional device, the movable plate may move forward at a high speed in the process of shifting to the boosting operation, which may damage the mold.
Therefore, in order to avoid this, the boosting operation is delayed by a predetermined time by a timer. Therefore, there is a problem that the cycle time of the injection molding machine is extended.

The present invention is intended to provide a control device for a mold clamping device, which can prevent the mold from being damaged and shorten the cycle time to solve the conventional problems.

(Means for Solving the Problem) Therefore, in the present invention, the means for detecting the movable platen position, the means for detecting the movable platen speed, and the movable platen position are provided in the mold clamping device that shifts from the mold closing operation to the boosting operation. Control to output a boosting start signal that shifts from the mold closing operation to the boosting operation by detecting that the boosting operation start position (position just before the die comes in close contact) is reached and the movable plate speed has become almost zero. And means for solving the problems.

(Operation) By adding the fact that the movable platen speed has become almost zero to the condition for shifting the boosting operation, the position where the pressure can start to be boosted by the limit switch (LS18) set by the operator is detected, and the movable platen speed becomes almost zero. After that, that is, after detecting that the mold is in close contact, the boosting operation is started. As a result, it is not necessary to provide a timer in the control device, and the cycle can be shortened.

(Embodiment) The present invention will be described below with reference to embodiments of the drawings.
2 and 2 show an embodiment of the present invention. In FIGS. 1 and 2, the movements of the actuators for the mold closing operation and the boosting operation and the hydraulic system are the same as those in the conventional example, and therefore detailed description thereof will be omitted here.

The points in FIG. 1 different from those in FIG. 3 will be described below. Reference numeral 31 is a speed detector for detecting the moving speed of the movable platen 2. The speed detector 31 has various mechanisms,
Any detector such as tachogenerator or encoder pulse interval measurement may be used. Further, the limit switch 23 (LS18) may be located a few mm before the mold contact position or almost at the mold contact position depending on the operator's setting.

In the case of FIG. 1, the control device 32 has a speed detector 31.
The signals from the speed information limit switches 21 to 23 from are taken in. The signal of this speed detector 31 is always a comparator
It is compared in 33 and a signal comes out when it becomes almost zero (actually about 5 mm / s or less). Also limit switch 23
The boosting enable signal 35 is output by the operation of the AND element 34 of the ON signal of (LS18) and the signal. Then, the contact 36 is turned on by this signal, and the SOL-PR of the solenoid valve 14 is turned on.
And the contact 37 is turned on, and the proportional flow valve 15
Increase the setting of and start boost operation. This timing chart is shown in FIG. The limit switches 21-23 are
It is also possible to replace with a stroke sensor. It is also possible to use this stroke sensor also as the speed detector 31.

(Effect of the Invention) As described in detail above, the present invention is provided with the control means for detecting that the movable platen speed has become almost zero and outputting the boosting start signal for shifting from the mold closing operation to the boosting operation. So
When the movable plate speed reaches approximately zero by detecting the position where the limit switch can start boosting, which is set by the operator, that is, after detecting that the die is in close contact, the boosting operation is started. It is not necessary to provide a timer in the device, and the cycle time is shortened.

[Brief description of drawings]

FIG. 1 is a system diagram of a mold clamping device according to an embodiment of the present invention, and FIG.
FIG. 3 is a timing chart according to an embodiment of the present invention, FIG. 3 is a system diagram showing a conventional mold clamping device, and FIG. 4 is a conventional timing chart. Description of main parts of the figure 2 …… Movable plate, 3 …… Fixed plate 4 …… Prefill valve 5 …… Clamp ram, 6 …… Core side mold 6a …… Cabinet side mold, 7 …… Booster ram 11. 12 …… Hydraulic source 21,22,23 …… Limit switch 31 …… Speed detector, 32 …… Control device 33 …… Comparator, 34 …… AND element 35 …… Boost start signal 36,37 …… Contact

Claims (1)

(57) [Scope of utility model registration request] 1. In a mold clamping device that shifts from a mold closing operation to a boosting operation, a movable platen position detecting means, a movable platen speed detecting means, and the movable platen position is a boosting operation starting position (the die is in close contact with each other). (A position immediately before the movement) and when the movable platen speed becomes substantially zero, the control means outputs a boosting start signal for shifting from the mold closing operation to the boosting operation. Control device for the mold clamping device.