JPS6147212A - Method of molding ceramic powder - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a hydrostatic press forming method C in which a sintered powder such as a ceramic powder is molded. It is known that the isostatic pressing method, in which uniform pressure is applied from all directions, has superior properties compared to other pressure molding methods in that a homogeneous powder compact can be obtained. However, since a rubber mold is used, there are many problems such as difficulty in molding into complicated shapes and expensive molds.

As a method to deal with the above problem, for example,
As described in Japanese Patent No. 18641, wax, hardened oil, and
There is a method of isostatic press molding a powder using a plasticizer used for mold manufacturing materials such as nylon, polyvinylidene chloride, cellulose acetate, celluloid, polyvinyl chloride, phenol resin, polyethylene, and polystyrene.

However, even with methods using these plasticizers, problems remain, such as the surface condition of the molded product being poor and the plasticizer itself not being able to maintain a desired shape.

[Problem that the invention seeks to solve]

The purpose of the present invention is to solve such problems of isostatic pressing,
An object of the present invention is to provide a hydrostatic pressing method that enables the molding of ceramic powder having a complicated shape.

(Structure of the Invention) The present invention involves casting a mold together with a plasticizer along the shape of an article to be molded, filling the mold with a desired ceramic powder, and closing the filling port of the plastic mold with the same plasticizer. After isostatic pressing, the plastic mold is removed by heating and melting or chemical treatment to obtain a desired molded product.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings, taking as an example a process procedure for molding U-shaped ceramic powder.

FIG. 1 shows a mold 6 in which a space 5 for molding ceramic powder is formed in a U-shaped metal frame 1 by a plastic material 2 and a metal frame 4.
The top view of the figure is shown.

2 to 5 are cross-sectional views taken along the line 1-1 in FIG. 1, showing the steps of the molding method of the present invention.

First, as shown in FIG. 2, a plastic material 2 made of wax, for example, is poured into a metal frame 1 to a thickness of several millimeters. Next, as shown in FIG. Set the second gold frame 4. Then, a plastic material 2" of the same quality as the first plastic material 2 is poured over this. After the plastic material 2" has solidified, the original mold 3 is taken out.
A space is formed in which the ceramic powder is filled.

Figure 4 shows the state after the prototype mold 3 is taken out, where 5 is a space for filling ceramic powder;
This indicates a molding space, ie, a mold, surrounded by a plastic material that forms the shape of the article to be molded and has the same shape and dimensions as the original mold 3. The shorter the distance between the plastic material surrounding the space and the mold, the better the molding. This leads to an improvement in the surface condition of the substrate afterwards, but in normal cases, about 5 states are appropriate.

As shown in FIG. 5, a ceramic powder 7 is vibrated into the mold 5 made of a 2.2° plastic material prepared in this manner, and the opening is covered with a plate 8 made of the same plastic material. Then, heated and molten plastic material 22 is poured in to seal it.

Next, the metal frame 1 is removed, and as shown in FIG. 6, the entire mold 6 is wrapped with rubber 9 and hydrostatically pressed, thereby making it possible to obtain a highly accurate molded product that has been subjected to hydrostatic pressure three-dimensionally. .

When pressurizing, it is necessary for the plastic mold to be easily plastically deformed without breaking, so the molding is performed at a temperature equal to or higher than the glass transition temperature (Tg) of the plastic material layer.

This glass transition temperature (Tg) means the temperature at which the plasticizer has appropriate flexibility, and for example, in the case of PVC, it is about 79°C.

Finally, as shown in FIG. 7, the mold made of plasticized material taken out from the isostatic press is removed by heating and melting or using a solvent to form a ceramic powder molded body 10.
get.

〔Example〕

A U-shaped ceramic powder molded body having a radius of 50-1 at the curved portion was molded based on the above process.

After filling a paraffin wax mold with the above ceramic powder using paraffin wax as a plasticizer, the same mold was heated to 1400 kg/cs+2 at a temperature of about 30°C using Latinx rubber as a cover material as shown in Fig. 6. Press molded. As a result, the surface condition is improved (dimensional accuracy and shape are improved).
We were able to obtain a ceramic powder compact that was faithful to the shape of the mold.

[Integrated effect]

According to the present invention, a ceramic molded body having a complex shape and uniform density can be manufactured in a short time without using a special mold, and the metal frame used can be used repeatedly, so it is economical. It also has the advantage of being beneficial.

[Brief explanation of the drawing]

The attached drawings are diagrams for explaining the present invention in detail. Fig. 1 shows the mold, Figs. 2 to 5 show the process before pressure molding, and Fig. 6 shows the state in which the entire mold is covered with a rubber material during molding. 71! 1 is a diagram showing a ceramic powder molded body after molding obtained by the method of the present invention (7).

Claims (1)

[Claims] 1. Forming a plastic material layer having a molding space inside the metal frame,
A method for molding ceramic powder, characterized by filling the molding space with ceramic powder, completely closing the filled molding powder with a plastic layer, and then covering with a rubber material and subjecting it to isostatic pressure molding. 2. The glass transition temperature (Tg) of the plasticizer layer during isostatic pressing
) A method for molding ceramic powder according to claim 1, characterized in that the above steps are performed.