JPH0459323A - Injection molding machine - Google Patents

Abstract

PURPOSE:To precisely control the feeding quantity of compressed air, by a method wherein the compressed air to be fed selectively by a valve device is controlled by a flow control device, its flow is detected, at the time of mold release of a molded product, the foregoing compressed air is injected and output of a flow meter is displayed. CONSTITUTION:Compressed air is introduced through a feed port 14 and sent to solenoid valves 16, 17 respectively by being ramified through an air filter 15. Although the solenoid valves 16, 17 are closed always, at the time of mold release, the valves are opened for a fixed time established by a timer and the compressed air is allowed to pass through the valves. Flows of the compressed air passed through the solenoid valves 16, 17 are controlled respectively by flow controlling throttle valves 18, 19 and spouted respectively from holes 11a, 12a of molds 11, 12 through flow meters 20, 21. On the one hand, digital indications of the flows of the compressed air through the flow meters 20, 21 are performed on the indicators 26, 27 of a monitoring device 22. An operator controls the flow controlling throttle valves 18, 19 by looking at indication so that the flows are attained to fixed flows.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an injection molding machine, and more particularly to a compressed air supply device for injecting compressed air from a mold when releasing a molded product.

(Prior Art) Conventionally, as a method for releasing a molded product in an injection molding machine, a device having a built-in actuator for pushing out an ejector plate of a mold is known. In order to make ejection by this actuator easier, there is a space between the molded product and the cavity or core of the mold prior to the eject operation.
A method called an air ejector that jets out compressed air is known.

(Problem to be solved by the invention) In such conventional injection molding machines, especially injection molding machines that are said to be ultra-high precision, the flow rate of compressed air used to release the molded product is a factor that affects the quality of the molded product. becomes. For example, in products whose optical properties are important, such as lenses and disks, the residual stress of the product changes depending on the amount of compressed air supplied, which may affect the refractive index and the like. Conventionally, the supply amount of compressed air has been adjusted by the basis weight using a simple flow rate regulator, and it has been difficult to accurately grasp and control the flow rate. Therefore, quality defects tend to occur due to uneven mold release caused by differences in the supply amount of compressed air.

It is an object of the present invention to improve such drawbacks in conventional injection molding and to provide an injection molding machine equipped with a compressed air supply device that can precisely control the amount of compressed air supplied.

(Means for Solving the Problems) According to the present invention, a valve means for selectively supplying compressed air, a flow rate adjustment means for the compressed air selectively supplied by the valve means, and a flow rate adjustment means for selectively supplying compressed air. a flow meter for detecting the flow rate of the compressed air adjusted by the means; a mold to which the adjusted compressed air is supplied and the compressed air is injected when releasing the molded product; An injection molding machine equipped with a display means is obtained.

(Example) An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of an injection molding machine of the present invention. The molds 11, 12 are arranged so that molten resin is supplied therebetween to produce a molded article 13 of a desired shape. Each mold 11, 12 is provided with holes 11a, 12a through which compressed air is blown out between the molded product 13 and the molded product 13. Compressed air is introduced from the supply port 14, branched off through the air filter 15, and sent to the respective solenoid valves 16 and 17. The solenoid valves 16, 17 are normally closed and open during demolding to allow compressed air to pass through for a predetermined period of time. The compressed air that has passed through the solenoid valves 16 and 17 is sent to flow rate regulating throttle valves 18 and 19, respectively. The opening degree of the flow rate adjusting throttle valves 18 and 19 is manually adjusted to set the flow rate of compressed air to an arbitrary value. The compressed air that has passed through the flow rate adjustment throttle valves 18 and 19 is sent to the hole 1 of the mold 11 and 12 via flow meters 20 and 21, respectively.
1a, 12H. The flow meter 20.21 is provided with a compressed air flow rate monitoring device 22. Flow meter 2
0.21 converts the flow rate of air passing through the inside into an electrical signal. For example, a heat generating resistor is placed within the air flow and the change in resistance value is output as a change in voltage. The output signals of the flowmeters 20.21 are amplified by signal amplifiers 22.23, respectively, and then amplified by the linearizers 24.21.
25. The linearizers 24 and 25 respectively correct the electrical signals so that the changes in the electrical signals are proportional to the changes in the air flow, and then send them to the indicators 26 and 27. Indicators 26, 27 display the flow rate, for example digitally. Note that the flow rate monitoring device 22 includes signal amplifiers 22, 23,
The linearizers 24, 25, indicators 26, 27, and other input/output terminals or switches (not shown) are unitized and configured to be incorporated into the molding machine.

Next, the operation of the injection molding machine of the present invention configured as above will be explained. Compressed air is introduced from the supply port 14, branched off through the air filter 15, and sent to the respective solenoid valves 16 and 17.

The solenoid valves 16 and 17 are normally closed, but upon demolding, they are opened for a predetermined time set by a timer or the like to allow compressed air to pass through. Solenoid valve 16.
The compressed air passing through 17 is connected to a flow rate adjusting throttle valve 1.
8.19, the flow rate is controlled by flow meter 2, respectively.
It is ejected from the holes 11a, 12a of the mold 11.12 through 0.21 mm. On the other hand, the flow rate of the compressed air flowing through the flow meter 20.21 is digitally displayed on the indicator 26.27 of the monitoring device 22. The operator uses this indicator 26.
While watching the display 27, adjust the flow rate adjustment throttle valves 18 and 19 so that the desired air flow is achieved. As a result, the air flow rate ejected from the holes 11a112a of the mold 11.12 can be set to an optimal value, and a constant amount of air flow can be always supplied, which can stabilize the quality of the molded product. can.

In the above embodiment, the flow rate adjustment throttle valve 18.19 was manually adjusted by the operator while looking at the indicator 26.27, but a proportional control valve is used as the flow rate adjustment throttle valve 18.19, and the indicator 26. The supply amount of compressed air can also be automatically controlled by controlling the opening and closing of the proportional control valve according to the display contents of 27.

(Effects of the Invention) According to the present invention described above, the amount of compressed air jetted into the mold when releasing a molded product can be accurately set to an optimal value, and moreover, a constant amount of air flow is always maintained for each molding. Since it can be supplied, the quality of molded products can be stabilized.

Furthermore, by adding a simple mechanism, the amount of compressed air supplied can be automatically controlled.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of an injection molding machine of the present invention. 11.12... Mold, 13... Molded product, 14...
Compressed air supply port, 15...Air filter, 16.17
... Solenoid valve, 18.19... Throttle valve for flow rate adjustment, 20.21... Flow meter, 22... Flow rate monitoring device, 26.27... Indicator.

Claims (1)

[Claims] A valve means for selectively supplying compressed air, a flow rate adjustment means for the compressed air selectively supplied by the valve means, and a flow meter for detecting the flow rate of the compressed air adjusted by the flow rate adjustment means. Injection molding characterized by comprising: a mold to which the adjusted compressed air is supplied and to which the compressed air is injected when releasing the molded product; and a display means for displaying the output of the flow meter. Machine.