JPS602164B2 - Rapid molding and drying method for ceramics - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides an improved method for manufacturing ceramics, in particular a method for rapidly molding ceramics using a potter's wheel rotating shaft. Regarding drying method.

Conventional ceramic manufacturing technology involves filling a plaster mold with pottery on a rotating potter's wheel, shaping it from above using a rotating molding tool, and
Using the water absorbing properties of gypsum, water is removed from the contact surface with the molded product, and the molded product is heated together with the mold using the heating device described below to release the molded product from the raw material water content of approximately 22 to 24%, with a moisture content of approximately 1.
It is dried to 3-14%, taken out and further dried in another device.

Previously, plaster molds that had absorbed water were dried in the sun, but now they are continuously dried in the same equipment in a cycle to prepare them for the next use. Wakishi here refers to the raw material that can be used for direct molding, which is made by kneading potter's clay in a shiren machine. The apparatus for these conventional drying methods, in which the molded product held in the plaster mold is heated together after molding, will be described below with reference to FIG. 1 of the accompanying drawings. 1. In the Proctor drying method (a), 1 includes a drying chamber maintained at a room temperature of 40 to 70 oo, 2 a rotating roll that transfers an endless chain 3, and 4 a molded product suspended from the chain 3 at appropriate intervals. If the molded item is a coffee tray, there are 70 fences in 2 rows of shelves (1 plaster mold in total).
4) is used.

5 is the position where the molded product is loaded into the fence 4 together with the mold, 6 is the position where the molded product is released from the mold, the space between 6 and 5 is an empty mold drying section, and the arrow indicates the direction of travel of the chain.

The time required from charging the molded product to releasing it from the mold in this drying chamber is approximately 2
It's time. 2. At the mouth of the jet drying method, 11 is a rotating roll that guides the endless chain 12, 13 is a fence for storing plaster molds containing molded products that are suspended from the chain 12 at appropriate intervals, and each shelf has two rows of fences. Approximately five kawara boxes (all plaster molds are made of ION solid wood) are used.

1 4 is a hot air duct, 15 is a jet outlet, 16 is a position where the molded product is placed in a bag on the shelf 13 together with the mold, 17 is a position where the molded product is released from the mold, the arrow is the running direction of the chain, 1
The period between 7 and 13 indicates the period of air drying. The hot air temperature from the hot air duct is 6-0, and the drying time is about 1 hour. Modern jet dry molding plants require about 4 molds and a drying time of about 20 minutes. 3. In the model diagram of drying method C using high frequency (ultra short waves), 101 is a drying chamber;
2,103 is an ultrahigh frequency oscillator, 104 is an air blowing window, 1
05 indicates the position where the molded product is charged together with the mold, 106 indicates the template position, and the arrow indicates the running direction.

This apparatus requires 3 to 4 molds and a drying time of 15 to 20 minutes. The three types of drying methods explained above have their own drawbacks, and the main ones are as follows: [1] Proctor drying requires a long drying time, so the number of molds increases.

{2-Drying If the room temperature is raised, the green part of the product will dry out earlier, causing green breakage. Regarding jut drying, {1-If the core of the jet nozzle goes out of order, cuts will occur, so a nozzle suitable for the product is required. '2' Hot air temperature and blowout amount give very subtle effects. '3' Equipment costs and fuel costs are high. {1} Equipment costs for ultrashort wave drying are high. '2) Consumes a lot of power. '3} Equipment maintenance costs are high. (4) It is necessary to rotate the mold for uniform irradiation.
To summarize the disadvantages of the drying method, the main ones are that it is necessary to have a large number of plaster molds, usually 40 to 12, in order to carry out continuous work with one molding machine, and the cost of drying equipment is enormous. In addition, it takes a long time to dry the molded product and the plaster mold until it can be released from the mold, and it involves operational difficulties such as edge breakage. It is therefore an object of the present invention to eliminate the above-mentioned drawbacks, to eliminate the need for drying of the mold,
Continuous molding and drying work can be performed with a small number of molds,
The object of the present invention is to provide a method that can significantly shorten molding drying time. The purpose of these is to heat a molding mold with a large heat capacity and excellent heat conductivity, mold the raw historical earth on the mold,
This is achieved by the rapid method for molding and drying ceramics of the present invention, which is characterized by drying the heated molded product by blowing air on it. To explain the present invention in more detail, the present invention does not use a conventional plaster mold, but instead uses a molding mold that has a large heat capacity and extremely high heat conductivity.

The heat capacity is increased by preheating this mold to a certain high temperature, filling it with Butashi material made by kneading china clay, and shaping it with a molding coin while rotating it on a potter's wheel. Heat is gradually conducted from the large mold with excellent heat conductivity to the molded product via the contact surface on the lower side, and water vapor begins to be generated, so air is blown from the upper side to accelerate drying. The mold used in the method of the present invention can be made of metal because it can withstand high temperatures and has excellent thermal conductivity; however, it is not limited to metal, and any material having the above-mentioned properties can be used. That's fine.

Copper is preferable as a metal due to its heat conductivity and value, but
It may also be made of stainless steel. Ordinary iron can also be used. Since the mold has a large heat capacity, it is desirable that the ratio of the overall capacity to the molded part be large. The temperature at which the mold should be preheated is preferably higher for faster drying effects, but rapid heating of the material at the contact surface, rapid generation of water vapor, and drying are undesirable, so the upper limit of the initial mold surface preheating temperature is is about 130qo
, the lower limit seems to be about 50oo. However, the drying speed is a problem that slightly affects the drying finish of the molded product, and in reality, there may be cases where the molded product is heated to a temperature outside this limit. Comparing the conventional method using a plaster mold and the method using the heated mold of the present invention, the former method first molds at room temperature, so during molding, moisture in the molded product decreases due to the hygroscopicity of the plaster. Moisture is absorbed by the plaster through the contact surfaces. When the molding is completed, the molded product is transferred together with the mold to the above-mentioned heating drying device, and the molded product is also dried by heating from the surface, and is dehydrated from the top and bottom to reach a moisture content that can be used as a template. In the latter method, molding is carried out in a heated mold, so the heat of the mold is conducted to the molded product during molding, and drying begins earlier, and the mold is sufficient to reduce the moisture content of the molded product by about 10%. Since it has a large heat capacity, drying can be completed quickly, and there is no need to dry the mold after it is released, so there is no need to prepare a large number of molds as in the former case. The drying time of the latter is also significantly shorter than that of the former. In addition, in the former case, drying occurs through the contact surface, so the contact surface dries and adheres, making it difficult to release from the mold, whereas in the latter case, the contact surface is slightly saturated with water vapor and remains. There is also the advantage that the mold is easy to make. In addition, in the case of plaster molds, the strength of the mold is not very strong, so the moisture content of pork soil used can only be around 22%, and if the moisture content is lower than this (for example, around 20%), the plaster mold will be destroyed. However, in the case of molds, there is no risk of breakage, so the moisture content of the mold can be lowered to a level that does not affect the work, which is advantageous in shortening the drying time. Furthermore, when using a plaster mold, the green part is often dried first, which is called drying, and in that case, the green part shrinks first, which causes tearing. Ta.

In the present invention, since drying occurs from the inside of the molded product, there is no need to worry about cutting the twill as in the case of high-frequency drying, and the above-mentioned ultrashort wave concessional drying, which was conventionally carried out with large equipment and expense, can be avoided. Jet drying is no longer necessary, resulting in significant savings in fuel and electricity. As described above, by implementing the present invention, the drying time is greatly shortened, the number of external equipment required for molding is small, and the maintenance cost is also incomparably economical, achieving a truly labor-saving and energy-saving method. It can be said that it does. Products that can be molded on a potter's wheel using the method of the present invention are usually plates, wells, bowls,
Tea cups, etc. Figure 2 of the accompanying drawings is an explanatory side view including a partial cross section of the molding potter's wheel shaft used in the present invention, and in this figure, 201 is a mold for molding, 202 is a molded object, and 203 is for fixing the mold. A dowel, 204 is a dowel rotating shaft, 205 is an eel for molding, and 206 is an eel rotating rattan.

Next, examples of the present invention will be shown. Example surface temperature, weight 8.57k heated to 120-130℃
Attach the iron mold No. 9 to the dowel shown in Fig. 2, fill the mold with 14 pieces of gauntlet material with a moisture content of 22%, and shape it with a molding tool while rotating the potter's wheel spindle to form the molded product. Air was blown onto the top surface to remove water vapor, and when the moisture content reached approximately 13%, the mold was released to create a coffee saucer.

The time required from molding to mold release was about 3 minutes. The weight ratio, which was replaced by the volume ratio, was about 5 stitches ago.

[Brief explanation of the drawing]

Fig. 1 is an explanatory drawing of the conventional ceramic drying method, A shows the Proctor drying method, C shows the jet drying method, C shows the equipment used for the drying method using high frequency, and Fig. 2 shows the equipment used in the method of the present invention. It is an explanatory side view including a partial sectional view of the molding potter's wheel shaft. In this figure, 201 is an iron mold for molding, and 202 is a molded product (
coffee saucer), 203 is a dowel for fixing the mold, 204
205 is a dowel rotation axis, 205 is a molding mirror, and 206 is a mirror rotation axis. Figure 1 Figure 2

Claims (1)

[Scope of Claims] 1. A molding die with a large heat capacity made of a metal selected from copper, an alloy mainly composed of copper, iron, and stainless steel is heated in advance, and the heated die is heated in advance. Attach it to the potter's wheel shaft, mold the raw material embryo soil on the mold and heat it from the inside,
A method for rapidly molding and drying ceramics that can be molded on a potter's wheel, which is characterized by removing emitted water vapor. 2. The method according to claim 1, wherein the mold is preheated at a temperature of 50° to 130°C. 3. The method according to claim 1, wherein the potter's wheel moldable ceramics include any one of a plate, a bowl, a teacup, and a teacup.