JPH03211008A - Slurry cast molding method - Google Patents

Abstract

PURPOSE:To shorten wall-forming time to a large extent and enhance efficiency of use of gypsum mold by heating a mold and slurry to be fed in in the molding of feeding slurry into a mold composed of gypsum or the like, forming walls on the inner face of the mold, and then opening the mold and releasing the wall-formed material. CONSTITUTION:A gypsum mold 1 is composed of a top force 2, a couple of lateral molds 3 and a bottom force 4 and which are engaged with together. First, slurry is injected and body is wall-formed in the mold inner surface, and the slurry in the gypsum mold 1 is discharged after the given time has passed. Further, after the given time has passed, the gypsum mold 1 is opened and a molded material is released. At that time, the gypsum mold 1 and slurry are heated respectively to shorten the wall-forming time. The temperature of said heat should in the range of 35-45 deg.C, particularly 38-42 deg.C is preferable. The reason why the wall-forming time is shortened by heting the gypsum mold and slurry is presumed that the viscosity of water contained in the slurry is lowered and that the speed to be absorbed into the gypsum mold is increased.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a slurry casting method, and particularly to a slurry casting method that can significantly shorten the time required for inking.

[Prior art] A slurry (a slurry made of powdered clay for molding) is injected into a molding space formed in a mold made of gypsum or the like, and unnecessary liquid in the slurry ( The slurry casting method, in which water (for example, water) is infiltrated into the mold, the remaining powdery clay is deposited on the inner surface of the mold, and then the mold is separated and the deposited material is taken out, is used for various hygienic purposes. Today, it is widely used as a method for manufacturing pottery and the like.

[Problems to be Solved by the Invention] In the above method, inking is performed exclusively by water absorption of the plaster mold, and there is a problem in that the inking process takes a long time.

[Means for Solving the Problems] The slurry casting method of the present invention involves supplying slurry into a mold made of gypsum or the like to form a deposit on the inner surface of the mold, and then opening the mold and depositing the slurry. A slurry casting method for releasing meat from a mold is characterized by heating a mold and the slurry supplied into the mold.

[Function] When the temperature of the slurry increases by heating the slurry and the mold, the viscosity of the water contained therein decreases, so the rate of absorption of water into the mold increases. For this reason,
Fleshing time is shortened.

By the way, in order to give the casting slurry good ink receptivity,
It has added thixotropy (rice and wheat properties). This is a measure of the change in viscosity of the slurry over time.

Before casting, the slurry is subjected to external forces such as moderate stirring, and its viscosity is low, but it is cast into the mold and remains in the mold until it is drained. Therefore, the viscosity of the slurry has increased compared to the initial stage.

As a substitute value for this change in viscosity of the slurry, the viscosity of the slurry is continuously measured from 0 to 5 minutes using a B-type viscometer, and the difference in viscosity between 5 minutes and 1 minute is called the viscosity.

Rice and wheat properties are greatly affected by slurry temperature, and the degree of influence differs depending on the slurry formulation.

In the examples described later, as shown in FIG. 2, the change in rice-like properties of the slurry was relatively mild in the 40±2°C range, so this 40±2°C was adopted as a temperature range that was easy to use in the actual process. (Depending on the type of slurry, there were cases where the temperature change in rice and wheat properties became smaller at temperatures above 50°C.) The rice and wheat properties of casting slurry vary depending on the type of product, type of slurry, and molding method. There is an optimal value.

For ordinary Western-style toilet bowls, a range of 250±20 cP is appropriate for ordinary casting. Aiming for this area, deflocculant is added to adjust the slurry.

If the rice and wheat quality is too low, the following problems will occur.

0 Decrease in ink receptivity ■Deterioration in plasticity ■Deterioration in the uniformity of molded body strength due to poor fluidity of the slurry On the other hand, if the stickiness is too high, ■Poor mud removal ■Into the molded body Inclusion of air bubbles; ■ Casting speed becomes slow, casting streaks become large and breakage is likely to occur; ■ Defects such as soft demolded products occur.

As shown in Figure 3, when the slurry is heated, the rice and wheat quality is 500±10
Approximately 0 cP is an appropriate range. This is a higher area than normal, but the following points are different compared to normal.

■ Since the time for sludge formation is shortened by heating, the flow during mud removal does not become large even if the grain quality is high. For this reason,
No mud drainage problems.

■ Due to heating, the movement speed of water from inside the base material after mud removal is high, and the molded product tends to become hard.

Therefore, the demolded product does not become soft.

■ Although it has a high quality of rice and wheat, it has good fluidity during casting, so there are few air bubbles mixed in.

[Examples] Examples of the present invention will be described in detail below with reference to the drawings. Although this example relates to a drainage casting method for producing a Western-style toilet, the present invention is not limited to the following example, and can be applied to molding various types of ceramics other than Western-style toilets. It can also be applied to casting methods other than mud casting methods.

FIG. 1 is a sectional view showing a plaster mold 1 used in the slurry casting method of the present invention. This plaster mold 1 is divided into an upper mold 2, a pair of horizontal molds 3 and a lower mold 4, the upper mold 2 covers the upper end surface of the horizontal mold 3, and the lower mold 4 fits into the horizontal mold 3 from below. .

In slurry casting, first, slurry is poured into a mold, and clay is deposited on the inner surface of the mold. After a predetermined period of time has elapsed, the slurry in the plaster mold 1 is discharged. After a further predetermined time has elapsed,
Open the plaster mold 1 and take out the molded product.

In this slurry casting method, by heating the plaster mold 1 and the slurry respectively, it was possible to significantly shorten the inking time. It was recommended that the heating temperature be 35 to 45°C, particularly preferably about 38 to 42°C.

The reason why heating the plaster mold and slurry shortens the inking time is thought to be because this heating lowers the viscosity of the water contained in the slurry, increasing the rate at which it is absorbed into the plaster mold. Ru. (In the case of normal pure water, the viscosity at 20℃ is 1
cP, but it decreases to about 0.28 cP at 100°C. ) Specific examples and comparative examples will be described below.

Example 1 A Western-style toilet bowl was molded by slurry casting using the plaster mold shown in FIG. The concentration of clay components in the slurry is approximately 1250g/J! It is. When the temperature of the slurry and plaster mold was set to 40±2° C., 60 minutes was sufficient for the inking time.

Comparative Example 1 A Western-style toilet bowl was molded in the same manner as in Example 1, except that the temperature of the slurry and plaster mold was set to room temperature (30° C.). The inking time in this case was 100 minutes.

[Effects] As is clear from the above examples, according to the present invention, the time required for inking can be significantly shortened. Also, for this reason,
It can also increase the efficiency of using plaster molds.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of the plaster mold, and FIGS. 2 and 3 are temperature characteristic diagrams of the viscosity of the slurry. 1...Gypsum mold, 2...Upper mold, 3...Horizontal type, 4
...lower mold. Listening experience (OCL)

Claims (1)

[Claims] (1) In a slurry casting method in which a slurry is supplied into a mold to form an inked object on the inner surface of the mold, the mold is opened and the inked object is released from the mold. A slurry casting method characterized by heating the slurry supplied inside.