In accordance with European standards, molding is divided into three main groups: A, B, C. These groups indicate the water content in the ceramic mass and the method of its molding. According to EN 14411.
Molding A is a plastic molding method.
A plastic clay mass with a moisture content of 15-25% is formed by squeezing out timber. Molding is carried out using a vacuum belt press using the extrusion method. The ceramic mass is compressed by the screw of a belt press and pressed through a replaceable mouthpiece attached to the end of the output cylindrical part of the press, passing through which a plastic clay bar takes the shape of a corresponding ceramic product, that is, the shape of a tile with a given thickness and width. A cutting device (thin wire), the operation of which is synchronized with the speed of movement of the clay bar, cuts the molded bar emerging from the mouthpiece of the press into pieces along the length of the tile, called a semi-finished product. The molded slabs come out of the press in doubles. After firing they are separated. Tiles produced by this method are called extruded and have a significant thickness of up to 30 mm.
Molding B – dry pressing, the so-called hard method.
Dry molded (pressed) tiles consist of a thoroughly mixed dispersed mass and are formed in a press under high pressure. The disadvantage of this method is that its metal consumption is almost 3 times higher than that of plastic (the number of technological operations increases, and, accordingly, the amount of production equipment used). Its advantage is that the duration of the production cycle is reduced by almost 2 times, the products have a more regular shape and more accurate dimensions. It is divided into semi-dry and dry methods. Semi-dry method .
Tiles using this method are formed from a mixture with a moisture content of 8-12%. Dry method . Press powder with this method is prepared with a moisture content of 2-6%. In this way, tiles with a compacted shard are produced: gres (stone-ceramic tiles) and porcelain stoneware.
Molding C is a slip method in which products are made from a multicomponent mass consisting of heterogeneous and difficult to sinter clays and additives. Products are cast from ceramic mass with a water content of up to 40%. This is the most ancient technology for molding ceramic tiles, but it is not widely used. Used for the manufacture of non-standard ceramic elements.