JPH0622804B2 - Method and device for low temperature heating and rolling of ceramics - Google Patents

Description

[Field of Industrial Application] The present invention relates to a rokuro molding method for ceramic clay, particularly a rotary trowel rolling molding method, and an apparatus used therefor.

[Prior Art] In the rotary trowel type rolling forming method as a typical example of the rokuro rolling method, in most cases, a metal material is used as a trowel material,
By heating this, a steam film is generated between the kneaded material and the iron which are contact-rolled, which prevents the kneaded material from adhering to the kneading material and keeps the contact between the kneaded material and the kneading material smooth (hereinafter referred to as heating iron It is called the Law, Japanese Patent Publication No. 30-6281). That is, according to the conventional rotary iron rolling forming method, a rotary iron (roller) carved from an iron or aluminum material is heated at a high temperature (about 100 ° C.) by a gas burner or an electric heater to form the iron and the forming clay during forming. Roll forming is performed while forming a film of water vapor between them.

[Problems to be Solved by the Invention] In the conventional method, the surface temperature of the trowel material is usually 95 ° C to 105 ° C.
If it is lower than this, the clay will adhere to the iron,
If it is higher than this, cracks occur on the back surface of the molded product. Therefore, it is necessary to always maintain the above-mentioned constant temperature, but there is a drawback that the work of always maintaining the constant temperature requires skill and the work environment becomes poor due to heat radiation. Furthermore, if the trowel is kept in a high temperature heating state, heat is transferred to the mounting member (for example, lever or rod) of the trowel, and the effect of thermal expansion due to the heating of each mounting member appears, and the position between the mold and the trowel is changed. It will be out of order, and an error will occur in the rotating shaft between the die and the iron. As a result, a change in the thickness of the molded product is unavoidable, which causes a problem that the precision of the shape of the molded product is deteriorated. Or, if the proportion of clay in the kneaded clay is not within a certain range (about 20% by weight or more), there are drawbacks such as cracking and adhesion problems, and stable molding cannot be performed. It was difficult to call it a roll forming method with good properties.

The present invention aims to overcome the drawbacks of the prior art methods described above.

[Means for Solving Problems] The rotary trowel-type rolling forming method of the present invention uses 50 to 6 roll forming irons.
A gas is ejected from the outside of the trowel surface between the trowel surface heated to 0 ° C. and the clay to form a thin gas film at the interface between the trowel surface and the clay, which is then roll-formed. To do.

Further, the rotary trowel-type heatable rolling forming apparatus of the present invention is a rolling forming trowel, and the trowel surface by ejecting gas from the outside of the trowel surface between the trowel surface of the rolling forming trowel and the kneaded clay. The gas supply means for forming a gas film at the interface with the kneaded clay and the trowel surface are 50 to 60.
It is characterized by having a heating means for heating to ℃.

[Preferable Embodiments] Embodiments will be described below with reference to the drawings.

In the present invention, when the iron 1 rolls the kneaded clay 3, a gas (preferably dry) is blown from the outside into the gap between the two by using preferably a cylindrical or fan-shaped nozzle 2, preferably along the rotation direction of the rokuro. It is convenient to use dry air as the gas,
It is not limited to this and generally an inert gas can be used.

As described above, the trowel surface is 95
It was necessary to heat to ~ 105 ° C, but in the method of the present invention, a gas film is formed at the interface between the iron and the kneaded clay, so it is 50
High-quality molding is possible by heating at a low temperature of -60 ° C.

Although the gas spray pressure varies depending on the shape and size of the molded product, it is usually about 0.1 to 0.5 kgf / cm ² , and is not necessarily 1 kgf.
No high gas pressure above / cm ² is required. According to the experiment, the amount of dry air supplied is 8 ″ when the trowel temperature is 60 ° C.
Approximately 30 / min is required for the plate, and at 50 ° C, it is 35 for 8 "plate
/ Minute is required.

For heating the trowel, the methods used for conventional heating trowels such as burners and electric heating can be applied.
Since the temperature is as low as 0 to 60 °, there is no danger of cracking of the molded product due to overheating, and strict temperature control is not required.

The gas is, for example, the contact portion 8 between the iron and the clay as shown in FIG.
If it is sprayed toward the surface, a gas film is likely to be formed at the interface.

Next, the trowel forced rotary rolling method will be described. An ordinary rotary rolling rokuro molding machine is provided with a gas supply nozzle 2 as shown in FIG. 1, and the space between the kneaded material and the molding surface of the trowel 1 heated to 50 to 60 ° C. In addition, while the compressed air is supplied from the outside, the trowel 1 is rotated by an independent trowel drive device through the shaft 6 to perform roll forming. At this time, an air film is formed at the interface between the iron and the kneaded clay by the supplied air, so that the molded product having a smooth surface can be obtained without the kneaded clay adhering to the iron. The wheel is composed of a die receiver (head) 5 fixed to the upper end of a die rotating shaft 7. A die 4 is mounted on the die receiver 5 and is driven and rotated via a shaft 7. The kneaded clay 3 is formed into a predetermined shape by the rolling and forming action of the iron 1.

In the roll forming of the present invention, the rotation of the trowel is generally in the same direction as the rotation of the rotary wheel (die) and a suitable peripheral speed difference is provided to obtain the rolling effect. Depending on the conditions such as kneaded clay, the trowel can be independently driven and rotated, driven to be rotated with respect to the wheel, or stationary, and is characterized in that the device or the mode of use is very wide. Therefore, it can be used for roll forming of ceramic materials in various fields. The trowel is not limited to a plate, but can be used for rotary rolling of cups and balls. Further, it can be applied to both the inner trowel type and the outer trowel type forming method.

In the present invention, the term "porcelain" is used in a broad sense, and it can be applied to the rolling and molding of other ceramic green compacts including whiteware.

Example As shown in FIG. 1, a plate was manufactured as follows using a rotary trowel type roll forming apparatus provided with an air blowing device 2 between the trowel surface of the rotary trowel 1 and the kneaded clay 3.

The rotary iron 1 is heated to 50 to 55 ° C. with a heating tool to remove water 21
~ 26% by weight of various kneaded clay (5 to 50% by weight of clay for imparting composition plasticity, kaolin, quartz, and feldspar mixed in a predetermined amount), and the size after firing has a diameter of 6 to 1
A 0.5 inch dish having a main part thickness of 4 to 5 mm was roll-formed. The rotation speed of the wheel was 320 to 360 rpm, the rotation speed of the iron was 300 to 340 rpm (in the same direction), and the ventilation was performed at an air pressure of 1.5 kgf / cm ² . As a result, a molded product of excellent quality was obtained in comparison with the conventional high temperature heating trowel, and showed good quality even after firing.

According to the experiment, a smooth surface equivalent to or better than a heating iron can be obtained in an 8-inch dish with an air flow rate of 15 / min or more.

By the way, if the same rolling forming is performed by the conventional high temperature heating trowel method (95 to 105 ° C: gas burner heating) using the same trowel and die, it is good if the water content is not kept at 21 ± 0.5 wt%. Could not be molded properly.

Comparative Experiment Results In the present invention, heating was carried out under the same conditions as those of the examples, and for the comparative example, the temperature and the rotation speed of the iron and the rotational speed according to JP-A-56-7581 were described without heating the iron. A comparison test with a method of blowing air (70 to 100 ° C.) was performed on the same dish as that of the example of the present application, and the yield and the production capacity (speed) were examined. The results are shown in the table below.

[Effects of the Invention] According to the present invention, the temperature of the iron is 4 times higher than that of the conventional heating iron method.
Since it can be lowered by 0 to 50 ° C, it is 1 to 5 than usual.
It is possible to use a kneaded clay having a water content of about wt%, and as a result, it is possible to reduce the load on the molding machine and the clay kneader. Note that the kneaded clay having the same water content as that of the conventional one can be used, and it can be applied to both the inner iron type and the outer iron type.

The features of the present invention are summarized as follows.

1) The heating temperature of the iron is low, so it is possible to save energy and improve the working environment.

2) Since the kneaded clay with a high water content can be molded, the molding machine,
You can increase the ability of the clay extruder.

3) Missing parts and cracks caused by overheating.

Further, as compared with the conventional heated air blowing method, a remarkable productivity innovation is achieved in which the yield is improved by about 30% in relative ratio and the manufacturing capacity per unit time is also increased by about 30%.

[Brief description of drawings]

FIG. 1 is a schematic view of a rotary trowel type rolling forming apparatus of the present invention. Further, FIG. 2 is a schematic view illustrating the blowing direction of gas. 1 ... Iron, 2 ... Gas supply nozzle, 3 ... Kneaded clay (molded product), 4 ... Mold, 5 ... Mold receiver, 6 ... Iron rotating shaft, 7 ... Mold rotating shaft, 8 ... The contact area between the iron and the clay.

Claims (2)

[Claims] 1. A potter's wheel rolling method, in which a gas is jetted from the outside of the trowel surface between the trowel surface heated to 50 to 60.degree. A rokuro rolling method for ceramics, which is characterized in that a thin gas film is always formed at the interface with soil. 2. A roll-forming trowel that can be heated, and a gas film is ejected from the outside of the trowel surface between the trowel surface and the clay of the roll-forming trowel to form a gas film at the interface between the trowel surface and the clay. A rotary trowel-type rolling and forming apparatus for ceramics kneaded clay, which has a gas supply means for forming a mortar and a heating means for heating the trowel surface to 50 to 60 ° C.