JPS58138612A - Injection mold - Google Patents

Abstract

PURPOSE:To reduce pressure in the cavity from before the beginning of vacuum casting of molding material until the completion of casting by a method wherein the filter through which gas is allowed to pass but viscous liquid is not allowed to pass is provided in the vacuum port of the mold through which the molding material such as synthetic resin, etc. is poured in vacuum. CONSTITUTION:In the pouring hole 3 for molding material, a vacuum exhaust tube has a dual structure, porous paper or plastic sheet 3a with pore diameters 1-50mu is arranged on the side of the cavity of the exhaust port and then glass nonwoven fabric or glass filter 3b with pore diameters 1-500mu are distributed. Further, sintered metal 3c with pore diameters 1-500mu is disposed. Regarding the combination of filters, in order to resist pressure due to vacuum and that due to hardening, paper or plastic sheet 3a or nonwoven fabric, with sintered metal 3c as the base or glass filter 3b alone can be used.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a casting mold for obtaining a voidless cast product when producing a cast product for use in flat voltage equipment.

Conventionally, cast products used in high-voltage 1-atm equipment are required to have a high degree of electrical insulation, so void-free cast products are essential. Vacuum casting is used in most cases to manufacture voidless cast products. Specific methods for vacuum casting include placing the mold in a vacuum tank and injecting the casting material under vacuum, or keeping the inside of the mold cavity under high vacuum and pouring the defoamed casting material into the mold. An injection method is used. However, in the former case, the casting operation is discontinuous, resulting in a manufacturing process with extremely low productivity.

Furthermore, in order to prevent overflow of the casting material injected into the cavity, the capacity of the injection port becomes extremely large, resulting in large material loss. On the other hand, in the latter case, it becomes a problem to continuously reduce the pressure inside the cavity from before the injection of the casting material starts until the injection is completed. In other words, it was necessary to close the vacuum valve before the casting material was introduced to the vicinity of the vacuum exhaust port. However, with this method, if the detection method to confirm that the molding material has been injected close to the exhaust port is not accurate, the timing of closing the vacuum valve will be delayed, and the molding material may be injected into the vacuum line. There is a risk of In addition, a detector for indicating the completion of injection and a pulp that operates based on that signal are required.
The structure of the casting mold becomes complicated, especially in the case of a mold that is divided into upper and lower parts, which has a disadvantage in that it is almost impossible to do so.

The present invention eliminates the drawbacks of the vacuum casting method as described above, provides an accurate injection completion signal for filling the molding material into the cavity, and furthermore, the present invention eliminates the drawbacks of the vacuum casting method as described above. To provide a casting mold that can reliably perform continuous depressurization operations.

Below, I will explain the diagram. Figure 1 shows a cross-sectional view of a mold that is divided into upper and lower parts. (1) (1) shows the upper and lower molds, and (3) shows the vacuum exhaust port equipped with a filter. ) can be attached and detached. (4) is the injection port for the casting material, and as shown in Figure 2, the vacuum exhaust pipe has a double structure, and the cavity side of the exhaust port is lined with porous paper with a pore size in the range of 1 to 60 microns. Alternatively, place a plastic sheet Cω, then place a glass nonwoven fabric or glass filter 〇lb) with a pore diameter in the range of 1 NIsOOt chron, and then place a sintered metal ωC) with a pore diameter in the range of 1 to 500 t chron. do. The combination of filters is
In order to withstand the pressure of vacuum and the pressure of injection and curing, paper or plastic sheet (
8a) or non-woven fabric or glass filter (8b)
It can also be implemented by a combination of only two. The pore size of the filter varies depending on the type of casting material to be injected, but be sure to set the minimum pore size on the cavity side and a filter with a large pore size on the exhaust port side. Namely.

The pore diameter of the filter in Figure 2 is (8m) <(80<Ql
Combining in the order of c) 0, 1. According to this invention, it is possible to reduce the pressure inside the cavity from the start of injection to the completion of injection with a simple structure without fail. It is extremely effective for manufacturing.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a casting mold showing an embodiment of the present invention, and FIG. 2 is a sectional view showing the main parts of FIG. 1. In the figure, (1) is the upper mold, (!) is the lower mold, (3)
is a vacuum exhaust port, ω is a porous paper or plastic sheet), (8b) is a glass nonwoven fabric or filter, ω
C) shows the sintered metal, and (4) shows the injection port. In Figure 1, the same reference numerals indicate the same or equivalent parts.・ Agent 11+ Nobu Nobu -. Figure 1

Claims (1)

[Scope of Claims] 13) Synthesis - A filter that allows gases to pass through but blocks viscous liquids such as the above-mentioned casting materials when performing vacuum casting of casting materials such as fats and synthetic rubbers. A casting mold characterized in that the is installed inside the vacuum exhaust port. (2) Filters are made of porous metals or inorganic and organic compounds with pore sizes ranging from 1 to 50 cm.
A casting mold according to claim 1, characterized in that the casting mold is made by: (3) The casting according to claim 1, wherein the filter is composed of a porous plastic sheet having a pore size of 1 to 1 microns and a glass filter having a pore size of 1 to 600+ t. Mold. (4) Claim No. 1, characterized in that the filter is made of paper or plastic sheet with a pore size of 1 to 50 microns and sintered metal with a pore size of 1 to 500 microns,
Casting mold described in Section 3.