JP2024021020A - Gas venting device for molds - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mold internal exhaust device that eliminates problems caused by insufficient depressurization inside mold cavities and runners in the manufacture of molded products using molds.

SOLUTION: Exhaust tops 1, each equipped with a notch groove K, an exhaust groove H, a recess N for a screw, and an external exhaust passage connection groove A, which are connected to each other, are buried in burial holes in the mold in continuity with the runner of the mold. The notch grooves K of the exhaust tops 1 are made to match the runner end and the external exhaust passage connection grooves A of the exhaust tops 1 are made to match the external exhaust passage, thereby obtaining a gas venting device for molds.

SELECTED DRAWING: Figure 1

COPYRIGHT: (C)2024,JPO&INPIT

Description

The purpose of the present invention is to quickly exhaust the gas in the mold during molding in order to reduce the amount of waste molding material remaining in the runner by applying it to molds for molded products of synthetic resins, metals, etc. This invention relates to a degassing device for a mold for a molded product in injection molding.

The inventor of the present invention has been conducting research for more than 20 years since the beginning of this century in order to improve the poor yield of injection molded products in injection molding, particularly injection molding of synthetic resins. These were made public as patents or patent applications, and experiments were conducted on designs that had previously relied on vague calculations or engineers' intuition, such as runner shape, runner arrangement, desirable mold structure for exhaust, etc. The basic idea of degassing that the inventor arrived at after repeated confirmations became widely known in the industry, and remains so to this day.

Patent No. 4085182 Patent No. 4096327 Patent No. 5413780 JP2022-083946 Patent application 2022-047551

The situation of air and fluid materials inside a mold for a molded product is different from the movement of fluid outside an aircraft body, and the application of calculated values in design can only be used as a very rough guide, and most mold processing involves trial production or failure. It can be said that it is completed by accumulating experience points through repetition. Therefore, for example, the cross-sectional shape of the runner part installed when creating a mold for a molded product is also influenced by fairly vague common sense, such as dimensions that can quickly supply fluid material and have no resistance during die cutting. in many cases.

As a result of repeated tests on the cross-sectional area of the runner section (i.e., the volume of waste material after product manufacturing), which has been designed based on conventional fixed ideas, we found that the cross-sectional area of the runner section was designed to effectively exhaust air from the runner section. It was confirmed that the purpose could be sufficiently achieved even with around 50% of the design based on conventional common sense.

If the prior art is applied to this problem, the runner part of the mold B as shown in FIGS. (It is not shown in this drawing because the dimensions are extremely small compared to the other parts, and the part where the exhaust groove exists is indicated by the symbol H) are connected, and the exhaust groove H is opened to the external exhaust passage O. As a result, the filling pressure of the fluid raw material fed to the runner R from the gate G in FIG. By quickly and reliably filling the fluid raw material into C, a molded product without defects can be obtained. In FIG. 7, the waste material portion R' created inside the runner R by the above operation is shown together with the protrusion K' corresponding to the cutout groove K.

According to the present invention, since the air inside the runner R can be quickly and reliably discharged from the end of the runner R, it is possible to quickly fill the fluid raw material to be fed, and the resistance to the filling is removed. It is possible to further reduce the longitudinal cross-sectional area of the runner R, which has the effect of enabling molding operations with high yields and significantly reducing waste materials.

FIG. 3 is a first perspective view of the exhaust top according to the embodiment of the present invention. FIG. 7 is a second perspective view of the exhaust top according to the embodiment of the present invention. FIG. 3 is a left side view of an exhaust top according to an embodiment of the present invention. FIG. 3 is a right side view of the exhaust top according to the embodiment of the present invention. FIG. 2 is an exploded perspective view of a mold and an exhaust top according to an embodiment of the present invention. FIG. 2 is an assembled perspective view of a mold and an exhaust top according to an embodiment of the present invention. 1 is a perspective view of a portion of waste material produced by an embodiment of the present invention; FIG. FIG. 2 is a theoretical perspective view of a mold according to an embodiment of the present invention. 9 is a cross-sectional view of the mold shown in FIG. 8. FIG.

The principle for carrying out the present invention is as shown in FIGS. 8 and 9, but it is not possible to carry out the machining of the runner R, cutout K, exhaust groove H, and external exhaust passage O in large quantities at the mold manufacturing site. It must be said that it is extremely difficult because there are technical requirements for the work. In order to eliminate this difficulty, concrete implementation has been made easier by embedding the exhaust frame 1, which summarizes the technical points of the present invention, in a mold.

The exhaust piece 1 as shown in FIGS. 1 to 4 includes a notch K, an exhaust groove H, a screw recess N, and an external exhaust passage connecting groove A, which communicate with each other. The exhaust piece 1 has a cylindrical shape, and this was given because it is the most reliable and simple way to drill the embedding hole 2 in which the exhaust piece 1 is buried, as shown in Figures 5 and 6, in the manufacture of the mold B. If the shape is suitable and there are no manufacturing problems, it is not limited to a cylindrical shape, but can be freely adopted such as a polygonal tube.

To install the exhaust top 1 in the mold B, as shown in Fig. 5, a embedding hole 2 is drilled into the mold B so as to be continuous with the runner R of the mold B, and the exhaust top 1 is buried in the embedding hole 2. , by aligning the cutout groove K of the exhaust frame 1 with the end of the runner R, and aligning the external exhaust passage connecting groove A of the exhaust frame 1 with the external exhaust passage O, the system is completed as shown in FIG. Incidentally, the screws that are screwed into the screw recesses N to fix the exhaust top 1 in the buried hole 2 are omitted to avoid complication of the drawing.

By providing an exhaust piece 1 that can quickly and reliably exhaust the air inside the mold, the present invention can significantly increase the yield of all molded products regardless of the material, and also improve the production of molded products. Since the amount of waste material generated can be reduced, it can be used to manufacture all types of molded products such as synthetic resins and metals.

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1... Exhaust piece 2... Buried hole B... Mold R... Runner K... Notch groove H... Exhaust groove O... External exhaust passage N... Recess for screw A...External exhaust passage connection groove G...Gate C...Cavity

Claims (3)

In injection molding or casting, a product is obtained by injecting molten material through a gate into the mold gap formed between the cavity and the core.
A degassing device for a mold for a molded product, comprising an exhaust piece buried between the outside of the mold and a runner that is installed on the cavity side or the core side and is continuous with the above-mentioned void. The exhaust piece has a notch groove and an exhaust groove that are continuous with the runner, and further has a conduction path that connects the exhaust groove with the outside of the mold, and a screw receiving recess for fixing the exhaust piece to the mold. 2. A degassing device for a mold for a molded article according to claim 1. 3. A degassing device for a mold for a molded product according to claim 1, wherein the exhaust piece is cylindrical.