JPH0941002A - Treatment of burr of injection molding of metallic powder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To rapidly remove the burrs generated during injection molding at a low cost at the time of producing metallic parts by an injection molding and sintering method of metallic powder. SOLUTION: The burrs 3 generated at the moldings 2 formed by molding a compd. for injection molding, which is prepd. by mixing and kneading the metallic powder and an org. binder, by an injection molding machine are removed by injecting gas having a prescribed pressure, a mixture composed of this gas and liquid, a mixture composed of the gas and solid and a mixture composed of the gas, the liquid and the solid thereto.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for removing burrs generated on a metal powder injection molded body.

[0002]

2. Description of the Related Art In the metal powder injection molding and sintering method, a compound in which wax, resin, etc. are mixed with metal powder to impart fluidity is injected into a mold using an injection molding machine, and the resulting molded body is degreased. This is a technique of manufacturing a metal part having a predetermined shape by removing (wax, resin, etc.) and sintering. Therefore, it is possible to manufacture metal parts having complicated shapes in large quantities and with high quality. Further, it is easy to manufacture a component made of a hard-to-work metal material or a high-melting metal material. Therefore, as a new metal working method following machining, forging, casting, and powder metallurgy, it has been spotlighted, and in recent years, the amount of parts produced by the metal powder injection molding and sintering method has been increasing.

However, similar to other processing methods, a bar is generated in the manufacturing process. That is, at the time of injection molding, the raw material compound oozes into the butting surface of the mold cavity and the core, and becomes a bar. Since the metal powder injection molding is a mixture of wax, resin and metal powder, it is relatively brittle, and in order to remove it in the state of the molding, it is generally used for parts manufactured by other metal processing methods such as machining. It cannot be removed by the used barrel polishing method. If it is removed after sintering, the barrel polishing method can be applied like other processing methods, but since it is a part having a complicated shape as compared with other processing methods, some parts cannot be removed by this method. Therefore, when the molded body is difficult to handle, it must be manually removed carefully. Manufacturing costs are high and it takes too many days.

FIG. 1 shows the removal of burrs using a conventional brush. In the figure, 1 is a burr treatment brush, 2 is a metal powder injection molding, and 3 is a burr generated by the metal powder injection molding.

[0005]

DISCLOSURE OF THE INVENTION The present invention provides a method for removing a large amount of burrs in a metal powder injection-molded article in a short time.

[0006]

A bar treatment method for a metal powder injection-molded article of the present invention is obtained by molding an injection-molding compound obtained by mixing metal powder and an organic binder whose main component is wax or resin. It is a method of injecting gas having a predetermined pressure, a mixture of gas and liquid, a mixture of gas and solid, and a mixture of gas, liquid and solid into the formed body to remove burrs.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION A method of bar treatment of a metal powder injection molded article will be specifically described below.

In the present invention, air can be used as a gas and water can be used as a liquid to be sprayed onto the metal powder injection molded body.
The solid is preferably in the form of particles of 10 to 200 μm. As the material, a resin that burns and decomposes in the degreasing step or a material generally used for honing processing can be used.

The pressure for injecting a mixture of gas, liquid and solid is 0.1 to 5 atm.

A mixture / mixture of metal powder, wax and resin was injected into a mold by an injection molding machine to prepare a molded body having a predetermined shape. The selected part is a part in which a bary occurs.
Air having a predetermined pressure, a mixture of air and water,
A mixture of air and a bead of nylon having a size of # 100 and a mixture of air, water and the above-mentioned bead were injected into the molding, and the presence or absence of removal of the bar was examined.

Example 1 A metal powder injection-molded article was prepared for 200 times.
Prepare 100 pieces, and remove 100 pieces manually by brushing
0 is the method of the present invention, that is, 5 atm of air is applied at the tip of 1 mmΦ
Nozzle was sprayed and the barrier was removed. A conventional brush and a metal powder injection molded body are shown in FIG. 1, and an injection nozzle and a metal powder injection molded body used in the method of the present invention are shown in FIG.

In the figure, 1 is a brush for burr treatment, 2 is a metal powder injection molding, 3 is a burr generated by the metal powder injection molding, and 4 is an injection nozzle.

The time required for the treatment was measured to evaluate the effect of the method of the present invention. The results are shown in Table 1. In the present invention, the treatment time is halved as compared with the removal by brush, and it has a sufficient effect in removing the ball.

[0014]

[Table 1]

Example 2 A molded body similar to that of Example 1
00 pieces were prepared, and a mixture of air at 2 atm and water at a flow rate of 2 l / min was sprayed from a nozzle having the same shape as in FIG. 2 and a tip diameter of 5 mmΦ, and the time required for treatment was measured. Table 2 shows the results. It can be seen that the method of the present invention is a superior removal method because it can be processed in a shorter time than removal by brush.

[0016]

[Table 2]

Example 3 A molded product similar to that of Example 1 was used.
00 pieces were prepared, and a mixture of 1 atm of air and # 100 nylon beads was sprayed from a nozzle having the same shape as in FIG. 2 and a tip diameter of 5 mmΦ, and the time required for the bary treatment was measured. The results are shown in Table 3. It can be seen that the method of the present invention is a superior baring method as compared with the baring method using a rotary brush.

[0018]

[Table 3]

Example 4 A molded body similar to that of Example 1
00 pieces were prepared, and a mixture of 1 atm of air, # 100 nylon bead and water of 2 l / mm flow rate was sprayed from a nozzle of the same shape as in FIG. The time was measured. The results are shown in Table 4. It can be seen that the method of the present invention is an excellent bar treatment method.

[0020]

[Table 4]

[0021]

INDUSTRIAL APPLICABILITY According to the present invention, an injection molding compound obtained by mixing and kneading a metal powder and an organic binder is molded by using an injection molding machine. The molding is gas, a mixture of gas and liquid, and a mixture of gas and solid. By injecting a mixture of a gas, a solid, and a liquid onto the molding, the ball can be removed in a short time at low cost.

[Brief description of drawings]

FIG. 1 is a view showing a conventional brush for burr treatment and a metal powder injection molded body.

FIG. 2 is a view showing an injection nozzle and a metal powder injection molded body according to an embodiment of the present invention.

[Explanation of symbols]

 1. Bare treatment brush 2. Metal powder injection molded body 3. 3. Bar generated in the metal powder injection molded body. Nozzle for injection

Claims (4)

[Claims] 1. A gas having a predetermined pressure is jetted to a metal powder injection-molded article obtained by molding an injection-molding compound obtained by mixing metal powder and an organic binder whose main component is wax, resin or the like. By doing so, the burr generated on the metal powder injection-molded body is removed, and the burr treatment method for the metal powder injection-molded body is characterized. 2. A gas and a liquid having a predetermined pressure in a metal powder injection-molded article obtained by molding an injection-molding compound obtained by mixing metal powder and an organic binder containing wax, resin or the like as a main component. By injecting a mixture of
A burr treatment method for a metal powder injection-molded article, comprising removing burrs generated on the metal powder injection-molded article. 3. A metal powder injection-molded article obtained by molding an injection-molding compound obtained by mixing metal powder and an organic binder containing wax, resin or the like as a main component, and a gas and a solid having a predetermined pressure. By injecting a mixture of
A burr treatment method for a metal powder injection-molded article, comprising removing burrs generated on the metal powder injection-molded article. 4. A gas and a liquid having a predetermined pressure in a metal powder injection-molded article obtained by molding an injection-molding compound obtained by mixing metal powder and an organic binder containing wax, resin or the like as a main component. A burr treatment method for a metal powder injection-molded article, characterized in that a burr generated in the metal powder injection-molded article is removed by injecting a mixture of: