JPH0234294B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a breathable durable mold, and more specifically, the present invention relates to a breathable durable mold, and more specifically, the mold is held at least on the side so that it can be easily attached to a table base of a plastic molding device, slip casting device, etc. This invention relates to a breathable and durable mold with a mold holding material formed by integrally fusing materials.

(Prior Art) The inventors of the present application first used metal powder and ceramic powder as aggregate, mixed it with a caking agent containing a component that evaporates or burns out, or further added and mixed reinforcing fibers in the form of a slurry. A composite fired body is obtained by pouring and molding a sample using a model or actual object, drying the molded body, and firing it in an oxidizing atmosphere. We are proposing a breathable and durable type with a porous structure that has a dense hardened layer. (Japanese Patent Application No. 59-23856 (Japanese Unexamined Patent Publication No. 60-166405)) However, this breathable and durable type is made of hard material, making it difficult to drill holes to attach it to the base of the molding device, and it is difficult to drill holes using a carbide drill. The hole must be drilled carefully over a long period of time,
Additionally, there were problems such as cracks occurring during the drilling process, making it difficult to attach to a breathable and durable base.

(Object of the Invention) The present invention was made in view of these problems, and an object of the present invention is to provide a breathable durable mold with a mold holding material that can be easily attached to the stand base of a molding device. That is.

(Structure of the Invention) The present invention consists of a composite fired body of metal powder and ceramic powder, and the composite fired body has countless pores throughout and has metal oxides dispersed in at least the outer peripheral part including the mold surface. The first invention is a breathable and durable type with a mold retaining material, which is characterized by having a dense hardened layer and having mold retaining materials integrally fused to the sides, and which is made of metal powder and ceramic powder. The composite fired body has countless pores throughout and has a dense hardened layer in which metal oxide is dispersed at least on the outer periphery including the mold surface, and has a dense hardened layer on the side and bottom surfaces. A second breathable durable mold with a mold retaining material is provided, characterized in that the mold retaining material is integrally fused and the mold retaining material on the side and/or bottom side is provided with a through hole that communicates with the outside from the surface of the composite fired body. This is an invention of the invention.

(Example) Hereinafter, an example of the present invention will be described based on the accompanying drawings.

As shown in Fig. 1, reference numeral 1 is a porous breathable durable mold.This breathable durable mold 1 is made of metal powder and ceramic powder, and has a dense hardened layer 2 on the outer periphery including the mold surface.
It also has a backing layer 3 made of an unfired mixed structure inside the hardened layer 2.

The hardened layer 2 consists of a bonding structure of metal oxide particles dispersed in ceramic powder and fired ceramic particles. Although the formation mechanism of this hardened layer 2 is not necessarily clear, it is generally considered to be the result of oxidation of metal powder and diffusion bonding at the interface with ceramic particles.

In this hardened layer 2, the binder is evaporated or burned away during the drying process and the firing process in an oxidizing atmosphere, resulting in fine particles (about 5 to 10 μm).
These fine pores form a porous yet dense and smooth surface. On the other hand, the backing layer 3 located inside the hardened layer 2
It consists of a mixed structure of metal powder and ceramic powder that have not been sufficiently fired, and pores are formed at the interface of the metal powder or ceramic powder due to evaporation or burning of the binder.
The pores of this backing layer 3 communicate with the pores of the hardened layer 2, so that the breathable durable type 1 has a porous ventilation structure as a whole.

Such a porous breathable durable type 1 is produced by mixing and kneading aggregate and a binder to obtain a slurry sample, pouring and molding the slurry sample, and drying or primary firing the molded body. It is obtained by a step and a step of firing the product through this step under oxidizing atmosphere conditions.

First, the process of obtaining a slurry sample involves thoroughly mixing and stirring metal powder and ceramic powder or steel fibers, and then adding a binder containing components that evaporate during the curing process, such as silica sol such as ethyl silicate or colloidal silica. and thoroughly mix and stir. Next, the slurry sample is solidified and molded into a desired shape to obtain a molded body. This is done, for example, by setting a model or actual object inside a mold, pouring the slurry sample into the mold, and leaving it for the required time. adding vibrations to promote the filling,
Squeezing is also effective.

Specifically, as the "metal powder", iron powder such as cast iron powder, electrolytic powder, pure iron powder, etc., and non-ferrous metal powder such as nickel powder, copper powder, etc. are used. Among these, cast iron powder has the advantage of promoting pore formation by burning free carbon during firing.

Ceramic powders include those that have a small deformation rate at high temperatures and are easily bonded to metal powders, such as neutral types such as mullite, calcined alumina, activated alumina, fused alumina, chromite, sillimanite, etc. Acidic materials such as silica, zirconium, and fused zircon are generally suitable, but basic materials such as magnesia and talc may also be used.

Furthermore, as the "steel fiber", stainless steel fibers are generally suitable. This is because stainless steel fibers do not disappear during the firing process, so they have a high reinforcing effect on both the hardened layer and the backing layer. Even if other steel fibers such as free-cutting steel are used, the reinforcing effect of the backing layer can be obtained, and the advantages of preventing cracks and preventing ceramic powder from falling off can also be obtained. Suitable steel fibers are ones that have high strength and a large surface area, such as those produced by a chatter vibration cutting method.

The mixing ratio of the metal powder, ceramic powder, and binder is preferably approximately (1-5):(1-5):1 by weight. Here, the lower limit of the mixing ratio of metal powder, ceramic powder, and binder is specified because it is necessary to obtain the minimum usable mold strength.

The upper limit was specified because too much aggregate would reduce the coating ability of the binder from the viewpoint of moldability, resulting in a decrease in strength and deterioration of the stability of the mold surface.

Next, after removing the molded body obtained in the previous step from the mold, natural drying and/or primary firing is performed,
Further, the molded body is subjected to secondary firing under oxidizing atmosphere conditions. The oxidizing atmosphere may be air or may be so-called oxygen-enriched air in consideration of oxygen supply. Firing conditions vary depending on the blending ratio of aggregates and binders, mold dimensions, target porosity, and production aspects, but in general, a firing temperature of 400 to 1500°C and a firing time of 1 hour or more are appropriate. However, the temperature and time are not limited to these, and as the firing time becomes longer, the hardened layer will grow and increase in size. Therefore, if you want to make the hardened layer thicker, you just need to lengthen the firing time, and if you want to make it thinner, you can shorten the firing time. In this secondary firing step in an oxidizing atmosphere, firing of the ceramic powder and oxidation sintering of the metal powder dispersed in the molded body proceed, and a dense hardened layer 2 is gradually generated from the surface toward the inside. At the same time, the volatile components of the binder remaining in the molded body are burned off to promote porous formation, and upon completion of the secondary firing, a porous breathable durable mold 1 as shown in Fig. 1 is formed. is obtained.

Next, as shown in FIG. 2, this breathable durable mold 1 is supported in a formwork 6 via the hollow cylinder 4 and the cylinder with screw holes 5, and a mold is placed on the upper surface of the breathable durable mold 1. A frame 7 is placed so as to surround the center part of the surface.

Subsequently, a molten metal such as zinc, alloy, aluminum alloy, etc. is poured into the space formed by the breathable durable mold 1, the mold 6, and the frame 7 as the frame material 8, and is solidified. After solidification of the molten metal, the mold 6 and the frame 7 are removed, and the peripheral surface of the solidified frame material 8 is processed to a predetermined size to form a mold holder 9 of a predetermined shape as shown in FIG. When attaching the breathable durable mold 1 integrally held by the mold holding material 9 to the stand base of a molding device (not shown), the screw hole 5a of the threaded cylinder 5 is inserted into the stand base. Install by screwing in the bolt inserted from the side.

In the above embodiment, the breathable durable mold 1 was supported in the formwork 6 through the hollow cylinder 4 and the cylinder with screw holes 5, and the frame material 8 was poured up to the side and bottom surfaces. The durable and breathable mold 1 may be placed directly on the bottom of the mold 6 and the frame material 8 may be poured only onto the sides of the durable and breathable mold 1. In this case, the hollow cylinder 4
Although the through hole 4a is eliminated, the entire back surface of the breathable durable type 1 is now open to the outside air.

Further, the through holes 4a and the screw holes 5a may not be formed using the cylinder body 4 and the cylinder body 5 with screw holes, but may be bored during processing of the solidified frame material 8.

Furthermore, there are cases where it is not necessary to provide the screw hole 5a, and in this case, the breathable durable mold 1 may be held on the table base via the mold holding material 9 using a lock cylinder or the like.

(Effects of the Invention) As is clear from the above description, the present invention does not require direct drilling of holes in the breathable durable mold, making the drilling process easy and without causing cracks during drilling. In addition, it is easy to attach to a breathable and durable table base, and the finishing dimensions are accurate, resulting in improved mold accuracy, and the effect of contributing to this type of industry is significant.

[Brief explanation of drawings]

1 to 3 are process sectional views showing an embodiment of the present invention. 1: Breathable durable type, 2: Hardened layer, 9: Mold holding material.

Claims (1)

[Scope of Claims] 1. Comprised of a composite fired body of metal powder and ceramic powder, the composite fired body has countless pores throughout and has metal oxides dispersed in at least the outer peripheral part including the mold surface. A breathable and durable type with a mold retaining material, which has a dense hardened layer and a mold retaining material integrally fused to the side surface. 2 Comprising a composite fired body of metal powder and ceramic powder, the composite fired body has countless pores throughout and has a dense hardened layer in which metal oxides are dispersed at least on the outer periphery including the mold surface. , a mold retaining material is integrally fused to the side surface and the bottom surface, and the mold retaining material on the side surface and/or the bottom surface is provided with a through hole that communicates with the outside from the surface of the composite fired body. Durable type.