JPS6030534B2 - Method for controlling molded product ejection from injection molding machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an ejection control method for an injection molding machine, and more particularly to a method for controlling ejection of a molded product, which is incorporated in a unit cycle for manufacturing an injection molded product of synthetic resin. By making the multiple ejection operations faster in the second G-pulling operation than in the first, the molded product is not damaged, mold release is ensured, and the time for one cycle is shortened. This invention relates to an ejection control method for an injection molding machine.

In a synthetic resin injection molding machine (hereinafter referred to as an injection molding machine), during the unit cycle sequence operation (hereinafter referred to as a unit cycle) for manufacturing a molded product, there is a process in which a protruding pin or plate is protruded to remove the molded product from the mold. There is a molding process, but in this case, the molded product is released from the mold cavity with one ejection, but it may be stuck to the ejector pins and cannot be completely removed from the mold.
It is widely practiced to completely release the molded product from the mold by ejecting the ejector pin or the like multiple times to prevent damage to the mold due to the molding operation in the next cycle.

The ejection speed of the ejector pins, etc. is set to prevent scratches caused on the surface of the molded product by the mold when molding from the mold cavity or core, and damage to the molded product due to the ejector pin itself.
It is set at a constant speed, and multiple ejection operations are performed at the same speed.

However, such a conventional mold release method has the disadvantage that the mold release process takes longer than a single mold release method, and work efficiency is greatly reduced. An object of the present invention is to provide a method for controlling the ejection of a molded product from an injection molding machine, which can eliminate such unreasonable time during sequence operation of a unit cycle and economically obtain a molded product. However, in a molded product ejection control method for an injection molding machine in which the molded product is released by ejecting the mold release pin multiple times during a unit cycle, the end of the first ejection operation of the mold release pin is detected by the position detection means. The present invention is characterized in that an electromagnetic proportional flow valve connected to a hydraulic circuit for protruding or retracting the mold release pin is controlled so that the speed of movement of the mold release pin increases from the second time onwards. Embodiments of the present invention will be described in detail below with reference to the drawings. Reference numeral 1 denotes a movable plate of an injection molding machine, which is attached to a mold vertical device (not shown) to the right in the figure, and moves to the left to close the mold, and to the right to close the mold.

Reference numeral 2 is a projecting pin and is provided via a projecting plate 5 to a projecting piston 4 that moves forward and backward within a cylinder 3 that is fixed to a movable plate 1.

Reference numeral 6 denotes a guide ratchet, which moves together with the protruding plate 5 and has a position detection dock 7 provided on a portion of the movable plate 1 that protrudes to the outside.
As it moves, it comes into contact with the proximity switch 8 and the reverse confirmation proximity switch 9.

The flow rate is controlled by a single hydraulic pressure source through an electromagnetic proportional flow valve 11, and is selectively sent to the front chamber 3a and rear chamber 3b of the cylinder 3 by a direction switching valve 12 operated by excitation of a coil.

Reference numeral 13 denotes an electric circuit for controlling the sequence operation, and includes a function of controlling the direction changeover valve 12 in response to signals from the proximity switch 8 and the reverse confirmation proximity switch 9.

Reference numerals 14 and 15 denote speed setting devices, and the setting value of the speed setting device 15 is set larger than the setting value of the speed setting device 14, and the electromagnetic proportional flow valve is controlled via a switching device 16 and an amplifying device 17.

Further, the switching device 16 receives a command from the electric circuit 13, the first operation of the ejecting pin 2 is performed through a signal from the speed setting device 14, and the operation of the ejecting pin 2 from the second time onwards is performed through the speed setting device 15. In addition, the backward motion of the protruding pin 2 is further away from the forward motion of the deviation, which shortens the unit cycle time, so the electromagnetic proportional flow valve 11 has a maximum flow rate The current value is such that the current can flow. Since it is configured as above,
When the injection molding is completed and the movable plate 1 retreats to the right, the direction switching valve 12 receives a command from the control electric circuit 13 and communicates with the rear chamber 3b of the cylinder 3, advances the ejecting pin 2, and The forward speed is slowed down in response to a signal from the speed setter 14 through the operation of the switching device 16.

As the ejecting pin 2 moves forward, the position detection dock 7 of the guide shaft 6 comes into contact with the proximity switch 8, which sends a signal to the electric circuit 13, and after the ejecting pin 2 stops moving forward, the direction switching valve 12 is activated. The protruding pin 2 communicates with the front chamber 3a and retreats. At this time, a current value that is larger than the current of the speed setter 15 and allows the maximum flow to flow through the electromagnetic proportional flow valve 11 is applied, and the protruding pin 2 retreats at a high speed. When the position detection dock 7 assists the backward confirmation proximity switch 9, the protruding pin 2 is prevented from moving backward by a signal, and the direction changeover valve 12 is operated again to communicate with the rear chamber 3b, and the protruding pin 2 moves forward. At this time, the signal from the speed setter 15 is received and the operation is performed further than the first operation. When the position detection dock 7 assists the proximity switch 8, the protruding pin 2 stops and moves back at an even faster speed, repeating this operation a set number of times, completing the unit cycle and returning the sequence operation to the initial state. to return to. Regarding the speed setters 14 and 15, an adder may be provided in place of the switching device 16, and when the speed is high, the speed increase may be set by adding the set values of the speed setter 14 and the speed setter 15. .

In addition, the proximity switches 8 and 9 can continuously detect the position with not only limit switches but also optical encoders, potentiometers, differential transformers, etc., and the position of the protruding pin 2 can be adjusted accordingly from the second time onward. By setting the distance short, it is also possible to further shorten the operation time from the second time onwards. As described above, according to the method according to the present invention, damage to the molded product caused by the mold or ejecting pins when releasing the molded product can be suppressed as much as possible, and the molded product can be reliably released from the mold.

Also, unreasonableness (redundancy) during sequence operation at the same time.
By effectively eliminating this time, the unit cycle time can be shortened, and in particular, the overall manufacturing time can be shortened, resulting in a significant efficiency improvement.

Furthermore, it can be implemented easily and at low cost by simply adding a flow rate control valve and the like to the existing hydraulic circuit.

Although the present invention has been variously explained above with reference to preferred embodiments, the present invention is not limited to these embodiments, and it goes without saying that many modifications can be made without departing from the spirit of the invention. It is.

[Brief explanation of drawings]

The drawing is an explanatory diagram showing sequence control of the present invention. 1...Movable plate, 2...Protruding pin, 3.
...Cylinder, 4...Protruding piston, 5...
Projection plate, 6...Guide shaft, 7...Position detection dock, 8...Proximity switch, 9...Reverse confirmation proximity switch, 10...Hydraulic pressure source, 11. ......Solenoid proportional flow valve, 12...Direction switching valve, 13...
Electric circuit, 14, 15... Speed setting device, 16.
...Switching device, 17...Amplification device, 3a...
...front chamber, 3b...rear chamber.

Claims (1)

[Claims] 1. In a molded product ejection control method for an injection molding machine in which a molded product is released by ejecting a mold release pin multiple times during a unit cycle, the end of the first ejection operation of the mold release pin is detected by a position detection means, Molded product ejection of an injection molding machine characterized by controlling an electromagnetic proportional flow valve connected to a hydraulic circuit for protruding or retracting the mold release pin so that the movement speed of the mold release pin increases from the second time onward. Control method.