JPH04808B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a method for casting ceramic products, which enables the production of hollow ceramic products of complex shapes with high accuracy in wall thickness.

(Prior technology) The slip cast method, in which slurry is injected into a water-absorbing mold and discharged from the inside of the mold after a predetermined period of time, is commonly used to mold hollow ceramic products with complex shapes. The wall thickness was controlled by controlling the time from pouring to draining. For this reason, when performing mass production using a large number of molds, the water absorption may change due to differences in the usage history of each mold (gypsum mold), mold temperature, etc., and changes in slurry viscosity and temperature may also affect the wall thickness. At present, the wall thickness could only be controlled in millimeters because the wall thickness was not constant. Therefore, the application of this method has been limited to items that do not require accurate wall thickness control, such as novelty and sanitary ware.

Recently, however, research has been conducted on ceramic port liners for lining the inner surface of automobile engine exhaust ports, and the slip cast method is attracting attention as a forming method. Strict wall thickness control of 0.1 mm or less is required because it affects engine output, and it has been impossible to meet this requirement using conventional methods.

(Problems to be solved by the invention) The present invention solves these conventional problems,
This method was developed for the purpose of creating a casting method for ceramic products that can form hollow ceramic products with complex shapes such as ceramic port liners and ceramic manifolds with high wall thickness accuracy.

(Means for Solving the Problems) The present invention has a slurry pouring spout, whereas conventional molds generally have a funnel-like shape with a constricted mouth for pouring and removing mud. The slurry is supplied to the inside of the mold, which has a straight shape with no restrictions, so as to keep the liquid level constant, and the thickness of the wall deposited at the end of the mold is measured. It is characterized by removing sludge.

Next, the present invention will be explained in more detail with reference to the drawings. 1 is a mold made of a water-absorbing material such as gypsum or water-absorbing resin, and its slurry inlet 2 has a funnel-shaped opening above the constriction part in conventional molds of this type. On the contrary, it has a straight shape as shown in the figure. Reference numeral 3 denotes a slurry supply pipe provided as necessary, and slurry 4 is injected into the mold 1 through this pipe 3. The slurry 4 is rapidly injected to the vicinity of the upper end surface of the mold 1, but after that, as the water in the slurry 4 is absorbed from the water-absorbing inner surface of the mold 1, the liquid level tends to gradually decrease.
It is preferable to supplement this and supply slurry continuously so that the liquid level of slurry 4 is always kept constant. Here, it is preferable that a liquid level gauge is set in the pipe 3 so that the slurry liquid level is always kept constant. At the same time, the deposited thickness at the mold end of the slurry pouring port 2 is directly measured by a measuring means 5 such as an optical sensor or a gauge. The slurry 4 may be colored to facilitate measurement, and in some cases, the thickness of the coating may be observed with the naked eye while comparing with a reference piece. In this way, when the wall thickness of the slurry 4 at the end of the mold reaches a predetermined value, the supply of the slurry 4 is stopped, and the mold 1
By removing the excess slurry 4 inside, a hollow ceramic product with an accurate wall thickness can be obtained. The liquid level at which the deposited thickness is measured may be set a certain distance below the upper end surface of the mold, as shown in FIG. 2, by sealing the vicinity of the mold pouring hole with water-impermeable paint 6 or the like.

With this method, it is possible to keep the wall thickness to an error of 0.1 mm or less, and it is not affected by differences in water absorption performance due to differences in the usage history of each mold. It becomes possible to mass produce ceramic products.

(Effects of the Invention) As is clear from the above description, the present invention has made it possible to mold ceramic products with complicated shapes, such as ceramic port liners and ceramic manifolds, with high wall thickness accuracy using the slip cast method. It has the advantage of being suitable for mass production without being affected by changes in water absorption performance due to differences in the usage history of each mold or mold temperature. Therefore, the present invention greatly contributes to the development of industry as a casting method for ceramic products that eliminates the problems of the conventional method.

[Brief explanation of drawings]

Figure 1 is a sectional view explaining the process of the present invention, Figure 2
The figure is a sectional view showing a modification thereof. 1: Mold, 2: Slurry inlet, 4: Slurry.

Claims (1)

[Claims] 1. The slurry is supplied into a mold with a straight slurry inlet without a restriction so that the liquid level of the slurry is kept constant, and the thickness of the wall deposited at the end of the mold is measured, A casting method for ceramic products characterized by removing mud when a predetermined thickness is reached. 2. The method for casting a ceramic product according to claim 1, wherein the mold is a mold for molding a ceramic port liner.