Production of CNC machine tool castings

Castings are mainly used as blanks for machine parts, and some precision castings can also be used directly as machine parts. Casting occupies a large proportion of mechanical products. For example, in tractors, the weight of castings accounts for about 50-70% of the weight of the whole machine, 40-70% in agricultural machinery, and 70-90% in machine tools and internal combustion engines. Among all kinds of castings, mechanical castings have the largest variety, the most complex shapes, and the largest amount, accounting for about 60% of the total casting output. Followed by ingot molds for metallurgy and pipelines for engineering.

　　 The quality of non-machined surface and appearance of castings has a considerable influence on the commercial properties of castings. They include:

　　 (1) Surface unevenness (box expansion, shrinkage and sand inclusion);

　　 (2) Surface or inner cavity cleanliness (sticky sand, sticky "paint layer");

　　 (3) Flatness deviation (unworked surface undulations);

　　 (4) Surface roughness;

(5) Contour definition (contour definition of structural units such as bosses and umbilicus, evaluated with the naked eye).