JPH06145715A - Production of parts from powder - Google Patents

Abstract

PURPOSE:To facilitate the production of a compacted product free from weld lines, shrinkage or the like and die production and to prolong the service life of dies by subjecting molded parts subjected to injection molding to final compacting by vibration compacting. CONSTITUTION:The powder of ceramics or metal is added with an organic binder and is thereafter subjected to injection molding into a molding (material 3) having a thin sheet shape or a blocky shape. This is clamped by an upper die 2 and a lower die 4, and after that, the material 3 is clamped by an upper punch 1 and a lower punch 5. Next, while being synchronized with the upper punch 1 and the lower punch 5, they are vibrated up and down and is compacted into a desired shape. The obtd. green compact is subjected to dewaxing treatment to remove the binder, and after being sintered, it is subjected to finish working to obtain the objective parts. Since the injection molding die molds a simple molded product, its structure is simple. By this injection molding, the voids in the completed parts can be reduced, and the dimensional accuracy can be improved. Furthermore, since the vibration compacting die requires no mechanism of a spool, runner, gate or the like and it is used under low pressure as well, it can be miniaturized and its production is easy.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention provides a method for manufacturing decorative parts, precision equipment, transportation equipment, electric / electronic equipment and the like using fine powders of ceramics and metals.

[0002]

2. Description of the Related Art In the case of producing a component by conventional powder injection molding, a precision mold is used to produce a component by injection molding a thermoplastic material containing ceramic or metal powder as a main component. . Therefore, in order to obtain a good molded product without weld lines, sink marks, etc., the structure inside the mold is complicated and the cost of the mold is high, and the mold wears due to the injection material and the dimensional accuracy is disturbed, so the mold life is shortened. The cost of parts was increased due to shortening and other reasons.

[0003]

In the injection molding method as described above, when the final molding of parts is performed by powder injection molding,
In order to obtain a good molded product without weld lines or sink marks, the structure of the mold is complicated, and there are many constraints on the mold design. Further, there is a drawback that the mold thus produced is worn out by the injection material and its dimensions are changed, so that the durability is short.

[0004]

The present invention is characterized in that the parts are molded in two steps of injection molding and vibration molding. The vibration forming method shows the principle of processing in FIG. Figure 1
As shown in (a), the material 3 is clamped (restricted) by the upper die 2 and the lower die 4 of the mold, and then the material 3 is clamped by the upper punch 1 and the lower punch 5. Next, as shown in FIG. 1B, the upper punch 1 and the lower punch 5 are vertically vibrated while being synchronized with each other to perform coining molding. When the material 3 is clamped by the upper die 2, the surrounding hydrostatic pressure is increased, and when the upper punch is clamped and then vibrated, the clamping pressure of the upper punch 1 and the vibration force of the upper and lower punches are applied to perform coining molding. As a result, a desired molded body is obtained.

The first step is a mold by injection molding, which can be easily manufactured by injection-molding a thin plate-shaped or block-shaped simple molded product, and can be manufactured in a desired shape with an inexpensive mold having a high dimensional accuracy and a long hole length. It is something that is done. The vibration molding die of the second step does not require a mechanism such as a sprue, a runner, and a gate, and can be molded at a low pressure without using high pressure such as injection molding, so that the mold can be made smaller than the injection molding and can be manufactured. It's easy. In the vibration forming, a plate-shaped material 3 as a work material is first clamped (restrained) by an upper die 2 and a lower die 4 of a mold, and then this sample is clamped by an upper punch and a lower punch. Next, the upper punch and the lower punch are synchronized with each other and vibrated vertically to perform molding. In the present invention,
The reason why the thin plate-shaped or block-shaped molded body is manufactured by injection molding of powder in the first step is to reduce voids in the finished part and improve the dimensional accuracy of the part.

[0006]

According to the present invention, a molded part obtained by powder injection molding is subjected to final molding by vibration molding, whereby a good molded product can be obtained without weld lines or sink marks which are defects in injection molding. Further, since the molding can be performed at a low pressure without using a high pressure such as injection molding, the mold can be made smaller than the injection molding and is easy to manufacture.

[0007]

【Example】

Example 1 To 85 parts by weight of SUS316L powder having an average particle diameter of 8μ was added 15 parts by weight of polypropylene, paraffin wax, and an organic binder to be stearic acid.
The mixture was heated and mixed at a temperature of 140 ° C. for 1 hour. This mixture is left to cool and solidify, then crushed and injection molded to a thickness of 3 mm and a length of 30 m.
A plate-shaped molded body having m and a width of 30 mm was prepared. After that, a mold having a pattern engraved on the upper surface of the men's watch case was attached to the vibration molding machine, and the molded body was attached to this mold to perform vibration molding. The molded body was degreased to remove the binder, sintered, and then subjected to finishing processing such as drilling and polishing to prepare a watch case.

(Example 2) To 86 parts by weight of an aluminum oxide powder having an average particle size of 0.5 μ was added 16 parts by weight of an organic binder composed of polystyrene, paraffin wax and stearic acid, and the mixture was heated in a kneader at a temperature of 160 ° C for 30 minutes. Mixed. The mixture was allowed to cool and solidify, and then pulverized to obtain a pellet-shaped molding material. Then by injection molding, thickness 2.5mm, length 30mm, width 25mm
Was molded into a block with a hole of 20 x 10 mm in the center.
After that, a mold formed in the shape of a women's watch case was attached to the vibration molding machine, and the molded body was attached to this mold to perform vibration molding. The molded body was degreased to remove the binder, sintered, and then polished as a finishing process to prepare a watch case.

(Example 3) To 86 parts by weight of zirconium oxide powder having an average particle size of 0.2 μ, was added 20 parts by weight of an organic binder composed of polyethylene, paraffin wax and polystyrene, and the mixture was heated in a kneader at a temperature of 160 ° C. for 30 minutes. Mixed. The mixture was allowed to cool and solidify, and then pulverized to obtain a pellet-shaped molding material. Next, injection molding to a thickness of 5 mm and an outer diameter
It was formed into a disc shape with a diameter of 35 mm and a hole with a diameter of 25 mm in the center.
After that, a mold molded into the shape of a women's watch case was attached to the vibration molding machine, and the molded body was attached to this mold to perform vibration molding. This molded body was degreased, sintered, and then polished as a finishing process to prepare a watch case.

[0010]

In the embodiments of the present invention, the case of the timepiece has been described, but it goes without saying that other mechanical parts, electronic parts, decorative parts and the like can be manufactured in the same manner. As described above, according to the present invention, it is easier to manufacture the mold than the conventional powder injection molding,
The cost can be reduced as a total process, and as a material, ceramics, metals, superhard materials, and composite materials thereof can be required, which is a great effect.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing each step of a method for manufacturing vibration molding according to the present invention, in which (a) shows a punch / die material clamped state, and (b) shows a vibrating coining state with punch vibration.

[Explanation of symbols]

 1 Upper punch 2 Upper die 3 Material 4 Lower die 5 Lower punch

Claims (1)

[Claims] 1. A method for producing a component containing ceramic or metal powder as a main component, wherein an organic binder is added to the powder and then injection molded to obtain a molded body, which is then mounted on a vibration molding machine. A method for manufacturing a component made of powder, which comprises mounting on a mold and vibration-molding, removing the binder by degreasing the resulting molded body, and finishing after sintering.