JPS60211B2 - Thermosetting resin casting equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a method for processing molten or liquid raw materials such as thermosetting resins (
This invention relates to a casting device that injects raw material resin (hereinafter referred to as raw material resin) into a mold and impregnates an object inserted into the mold.

In the conventional casting method, a coil or the like is impregnated with the raw material resin to form an insulator or the like, as shown in Fig. 1, a mold 1 into which a coil or the like (not shown) to be an insert is inserted is placed into a vacuum tank 2. The interior of the mold 1 is evacuated in the direction of arrow a using a vacuum pump (not shown) so that the raw material resin penetrates well between the coils, and the vacuum tank 2 (not shown) is used to promote hardening of the raw resin. When the temperature and degree of vacuum inside the mold 1 reach a predetermined value, the raw material resin 4 in the raw material tank 3 is heated by a heater that does not contain the raw material. After injecting resin until it is filled with resin, the mold 1 is taken out from the vacuum tank 2 and transferred to a curing furnace (not shown) for curing.

However, when curing the raw material resin in the mold 1, pods and residual stress are generated due to shrinkage due to curing, so it is common to harden gradually at low temperatures over a long period of time.

As a result, the molding cycle is long, and a large amount of space is required to leave the mold for a long time in order to harden the raw material resin, resulting in poor productivity. The purpose of the present invention is to eliminate the above-mentioned drawbacks and provide a highly productive impregnating machine with a short molding cycle. The pressure gelation method uses a highly reactive raw material resin, heats the mold to speed up curing, and injects new uncured resin into the mold to compensate for the shrinkage caused by rapid curing. This device is equipped with a vacuum device that evacuates the inside of the mold so that the raw material resin penetrates well between the coils, etc. An embodiment of the present invention will be explained with reference to FIG. 2, where 11 is a raw material tank. The raw resin contained in the mold 12 is passed through a resin passage 13 to a nozzle 15 for injecting the raw resin into the mold 14.

The nozzle 15 has a valve body 1 that operates to open and close a nozzle hole 16 at the tip of the nozzle 15 using air pressure.
7 is provided to control the injection of the raw material resin 11 into the mold 14. The mold 14 can be heated by a heating device 18 such as a heater, and the nozzle 15 and the fixed plate and moving plate described later are connected to a heat insulating plate 19.
At the same time, a suction hole 21 for removing air etc. from the mold cavity 20 is provided. A vacuum chamber 22 is attached to a fixed plate 23, with the movable plate 23 as the bottom, and a movable plate 24.
The side is closed, and when the molds attached to the fixed plate 23 and the movable plate are closed and engaged together, the movable plate 24 and the closed edge of the vacuum chamber 22 are supported through the packing 25. It has become.

The vacuum chamber 22 is provided with a degassing hole 35 for degassing the air inside the internal cavity 26 and the mold cavity 20.
is provided, and degassing is possible with a vacuum pump 28 via an electromagnetic switching valve 27. Reference numeral 29 denotes a plug that opens and closes the suction hole 21 for deaerating the inside of the mold cavity 20, and is operated from the air cylinder 3, and the mold cavity 2
The suction hole 21 is closed immediately before the inside of the chamber reaches a predetermined degree of vacuum and the raw resin 11 is injected.

Reference numeral 31 is an electromagnetic gate valve for controlling degassing in the raw material tank 12.

32 is an electromagnetic switching valve for opening and closing an air supply circuit for feeding and pressurizing air into the raw material tank 12.

The operation of the apparatus according to the present invention, which is constructed as described above, will be explained next. During pouring, the stopper 26 is moved back (toward the left in the figure), and the electromagnetic switching valves 2T and 31 are set to the B position to close the vacuum circuit. Then, a coil (diagram) serving as an insert is placed in the mold cavity 20 at a predetermined position.

Then, when the moving plate 24 moves forward (upward in the figure) and the mold 14 closes, the valve body 17 of the nozzle 15 closes the nozzle hole 16,
When the electromagnetic switching valves 27 and 31 are set to the A position, when the vacuum chamber 22, cavity 20, and raw material tank 12 reach a predetermined degree of vacuum, the air cylinder 30' causes the plug 29 to close the suction hole 21 of the mold 14 to the nozzle hole. 16 is opened, and the raw material resin 11 in the raw material tank is injected into the cavity 20 from the nozzle 15 via the resin passage 13 due to its own weight. At this time, the inside of the raw material tank 12 and the inside of the cavity 20 are in a deaerated state and no air or the like is present, so that no air bubbles are formed during casting.

Further, the raw material resin 11 descends under its own weight and enters the cavity 20, but when the vacuum suction is cut off, that is, the electromagnetic switching valve 31 is set to the B position and the leak valve 33 communicating with atmospheric pressure is opened via the throttle valve 34. Since a pressure difference occurs inside the cavity 20, the raw resin 11 can easily enter the cavity 20.

Returning again to the above-mentioned operation and continuing the explanation, when the cavity 20 is filled with resin and there is no need to worry about air bubbles being drawn in even if the vacuum state is released, the electromagnetic switching valves 27 and 3 are closed.
When the vacuum circuit is closed and the electromagnetic switching valve 32 is set to A position, the inside of the raw material tank 12 becomes pressurized, and the raw material resin injected into the cavity 20 is pressurized, and the mold 1
Curing is accelerated by the heating action of the heating device 18 provided at 4, and when the cavity 20 contracts, uncured raw material resin 11 is replenished into the cavity 20 by pressurizing the raw material tank 12. This eliminates the effects of voids, cracks due to curing shrinkage, residual stress, etc. that occur in the past.

This example is an example of molding a coil etc. with a long lead wire, and the explanation was given assuming that the lead wire comes out of the mold cavity. When a cavity is provided in the mold for storage, a vacuum chamber around the mold is unnecessary.

[Brief explanation of drawings]

FIG. 1 is a diagram showing a conventional example. FIG. 2 is a diagram showing an embodiment according to the present invention. 11... Raw material resin, 12... Raw material tank 15... Nozzle,
17... Valve body, 18... Heating device, 2
0... Mold cavity, 21... Suction hole, 22... Vacuum chamber 28... Vacuum pump, 29... Plug. Shio'kanji figure 2

Claims (1)

[Claims] 1 a One end is frame-shaped with a fixed plate for attaching a fixed mold as the bottom, and the other end is open, and when the movable mold attached to the movable plate engages with the fixed mold, the opening edge of the other end a vacuum duct which is in contact with the movable plate through a gasket to keep the inside of the frame airtight; b) the vacuum duct when the fixed mold and the movable mold are engaged and integrally form a cavity; a mold that is surrounded on the outside by a mold and has a suction hole that can be opened and closed and that communicates from the cavity to the inside of the vacuum duct; (c) a valve nozzle for injecting raw resin that has a valve body that opens and closes the nozzle hole inside; , d a raw material tank that stores raw resin therein and supplies the raw resin to the valve nozzle that can be pressurized and depressurized; e a raw material tank that deaerates air etc. from the vacuum duct and cavity a vacuum piping device piped to reduce the pressure of f
an air piping device for controlling the opening and closing of the valve body of the valve nozzle and the suction hole of the mold, and pressurizing the raw material stored in the raw material tank; A thermosetting resin casting device consisting of a heater that accelerates the curing of raw resin.