Gas-exhausting apparatus for die casting machine

Abstract

To solve the following problem in which: in molding operations using a mold such as die casting, removal of air or gas that remains in a cavity of the mold has long been a research issue, and in some cases, when filling and casting a metal material, an appropriate means for gas exhaust has not been provided.SOLUTION: In a die casting machine provided with a gate communicating with a cavity of a molding die in a runner that is continuous with a sprue, an exhaust pin is inserted into an exhaust hole formed in a fixed mold part of the runner. A plurality of V-shaped notches, each having an end opened toward the runner, are provided in any desired number on the peripheral edge of an end face of the exhaust pin facing the runner. A fine exhaust groove for exhaust is formed from an apex of the V-shaped notch farthest from the runner to the other end face of the exhaust pin, and the fine exhaust groove opens into an exhaust groove formed on an end face of the fixed mold part. By using a filling pressure of the molten material, air or gas in the cavity is discharged to an outside of the die casting machine.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a degassing device for injection molding, which involves filling a mold with molten raw material to manufacture various products, and in particular to a degassing device for die-casting machines that use metallic materials. [Background technology]

[0002] As a result of research conducted over the past twenty-odd years, the inventors of this invention have discovered that in order to fill a mold with molten material in a more desirable state during injection molding, it is desirable to use the filling pressure of the material to generate a sudden reduction in pressure, which then expels the air or gas from within the mold cavity to the outside of the mold, rather than using the filling pressure of the material to push it out. Based on this inventive concept, they have designed more desirable degassing devices for each molten material and mold structure. The details of such technological developments are described in the patent documents listed below. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 4085182 [Patent Document 2] Patent No. 4096327 [Patent Document 3] Patent No. 5413780 [Patent Document 4] Patent No. 7357232 Summary of the Invention [Problem to be solved by the invention]

[0004] Die casting is a casting method in which molten non-ferrous metal alloys such as aluminum, zinc, and magnesium are poured into a mold at high speed and pressure to form the part. When material flows into the gaps that form at the mating parts of the mold, burrs are generated due to improper mold alignment. For example, when using aluminum material that is molded at high temperatures of 650°C or higher, if unexpected deformation occurs in the mold, the material will leak out through gaps that form on the mating surfaces of the mold, forming burrs.

[0005] Furthermore, in order to quickly fill the cavity with high-temperature metal material, openings are intentionally created in the cavity to help expel internal air or gas, and it is not uncommon for the material to overflow into the opening and form burrs. In addition, due to inadequate temperature control of the material and its specific gravity, the material may not be distributed sufficiently inside the cavity, resulting in problems such as short circuits, rough surfaces, and cracks. [Means for solving the problem]

[0006] In a die-casting machine in which a gate that communicates with the cavity of a mold is installed in a runner connected to a sprue, an exhaust pin is inserted into an exhaust hole squeezed into the fixed mold part of the runner, and an arbitrary number of V-shaped notches with their ends open toward the runner are installed on the peripheral edge of the end face of the exhaust pin facing the runner, and a fine exhaust groove is drilled from the apex of the V-shaped notch farthest from the runner to the other end face of the exhaust pin, so that the fine exhaust groove opens into the exhaust groove squeezed into the end face of the fixed mold, and air or gas inside the cavity is exhausted to the outside of the die-casting machine using the filling pressure of the molten material. [Effects of the Invention]

[0007] According to the present invention, the necessary and sufficient number of gates, exhaust holes, and exhaust pins can be installed on the runner, so that, regardless of the material or size of the product to be molded, it is possible to mold a more highly finished product that does not require finishing processing or polishing, and this has the effect of enabling die casting molding with a good yield. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 2 is an exploded perspective view of the essential parts of the embodiment of the present invention. [Figure 2] FIG. 2 is an overhead perspective view of the main part of the embodiment of the present invention. [Figure 3] FIG. 2 is a vertical cross-sectional view of the exhaust pin taken along line AA in FIG. 1. [Figure 4] 2 is a vertical cross-sectional view of the exhaust pin taken along line BB shown in FIG. 1. [Figure 5] FIG. 1 is a reference diagram showing an exploded overhead view of an embodiment of the present invention; [Figure 6] FIG. 1 is an exploded perspective view showing a mold and a molded product according to an embodiment of the present invention. [Figure 7] FIG. 2 is a perspective overhead view showing a runner and a molded product cast according to an embodiment of the present invention. [Figure 7] FIG. 7 is an enlarged perspective view of the runner portion shown in FIG. 6. DETAILED DESCRIPTION OF THE INVENTION )

[0009] As an example, a case where a cylindrical tube made of an aluminum alloy is formed will be described. [Example]

[0010] In Fig. 5, 1 is a fixed mold in which an exhaust hole 2 is formed to accommodate an exhaust pin 3, 4 is an exhaust groove that connects the exhaust hole 2 to the outside of the fixed mold 1, and 5 is a pressure plate that comes into close contact with the fixed mold 1 to maintain the exhaust pin 3 inside the exhaust hole 2. The exhaust groove 4 may be formed arbitrarily on the surface of the fixed mold 1 or the surface of the pressure plate 5.

[0011] Reference numeral 6 denotes a movable mold equipped with a runner 61 and a gate 62 connected to it, which can be separated from the mold 7 for the molded product but operates as a single unit during casting. In the figure, 7' denotes the molded product formed in the mold 7 for the molded product, 61' denotes the casting waste remaining in the runner 61, and 62' denotes the casting waste remaining in the gate 62. Also, 4' denotes the casting waste that entered the exhaust hole 4 from the runner 6 and was stopped by hitting the end of the exhaust pin 3, and these casting waste 61', casting waste 62', and casting waste 4' are discharged out of the mold as a single unit when the molded product is removed.

[0012] In this embodiment, the exhaust pin 3 is cylindrical, and has a V-shaped notch 31 that opens downward on the periphery of the lower end facing the runner 61 in the figure, and a fine exhaust groove 32 is drilled from the apex of the V-shaped notch 31 that is farthest from the runner to the other end face of the exhaust pin 3, and this fine exhaust groove 32 opens into the exhaust groove 4 of the fixed mold 1. The exhaust gap between the exhaust hole 2 and the exhaust pin 3 is created by the fine exhaust groove 32.

[0013] The structure and operation of the V-shaped notch 31 and the fine exhaust groove 32 are repeatedly described in detail in the patent rights owned by the applicant of this application which are described in the prior art documents, so the following will suffice to say that the gas or air pressurized in the triangular pyramid-shaped space formed by the exhaust hole 2, exhaust pin 3, and V-shaped notch 31 is discharged into the exhaust groove 4 from the fine exhaust groove 32 which opens at the apex of the triangular pyramid, creating a great decompression effect, reducing the pressure inside the cavity, gate, and runner inside the mold to nearly zero, thereby eliminating to the greatest extent possible factors that hinder the progress of the molten metal being filled, thereby improving the quality of the product, reducing the frequency of mold cleaning, and creating a working environment with a relatively good yield.

[0014] Figure 6 shows a molded product 7' formed by one-shot filling casting, and the associated gate 61 and runner 62, as well as the casting waste 61', 62', and 4' produced by the exhaust hole 4. Figure 7 shows an enlarged view of the casting waste, which also shows the shape of the casting waste 4' of the exhaust hole 4 formed by the exhaust hole 4 in the fixed mold 1, and the protrusion 31' formed by the V-shaped notch 31 in the exhaust pin 3. [Industrial Applicability]

[0015] These explanations have been given with molten metal filling casting in mind, but the present invention can be used not only for metal die casting but also for the manufacture of various synthetic resin molded products using molds, making it applicable to a wide range of industries. [Explanation of symbols]

[0016] 1 Fixed type 2 exhaust vents 3 exhaust pins 4 Exhaust groove 5 Pressure plate 6 Movable type 7. Mold for molding 7' Molded product 31 V-shaped notch 32 Micro-grooves for exhaust

Claims

1. In a die-casting machine having a gate in a runner connected to a sprue that communicates with the cavity of a mold, a gas venting device for the die-casting machine is provided, in which an exhaust pin is inserted into an exhaust hole formed in the fixed mold portion of the runner, an arbitrary number of V-shaped notches are formed on the peripheral edge of the end face of the exhaust pin facing the runner, with the end opening toward the runner, and a fine exhaust groove is drilled from the apex of the V-shaped notch farthest from the runner to the other end face of the exhaust pin, so that the fine exhaust groove opens into the exhaust groove formed in the end face of the fixed mold.

2. 2. A gas venting device for a die casting machine according to claim 1, wherein the exhaust groove on the end face of the fixed mold is formed perpendicular to the axis of the exhaust pin.

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