Precision machining parts

How to determine the casting surface of precision machined parts

The position of the precision machined part in the mold during pouring affects the quality, dimensional accuracy, and difficulty of the molding process. Most of the thickness of the precision machined parts should be placed on the top, or on the side of the parting surface, the main purpose is to facilitate the placement of the riser in the thick part for feeding.

Selection principle of pouring position:

The important processing surface or the main processing surface of the precision casting is facing down or on the side: during pouring, the gas, slag in the molten metal and the sand in the mold will float up, which may cause pores, slag inclusions, sand holes, etc. on the upper part of the casting Defects, and under the possibility of defects in the lower part of the casting, the structure is denser.

The pouring position of the machine bed should have the guide rail face down to ensure the quality of this important working surface. The quality of the circumferential surface is relatively high, and the vertical casting scheme can be used to make the circumferential surface on the side to ensure uniform quality. The large plane of the precision machined parts is poured downward or inclined: due to the strong heat radiation of the hot molten metal to the upper part of the mold during pouring, the top surface of the sand mold will expand and arch or even crack, causing defects such as sand inclusions and sand holes on the large surface. . The large flat surface is facing down or the method of oblique pouring can avoid the large flat surface production casting defects.

The thin wall of the precision machined part is facing downwards, standing on the side or inclined: In order to prevent the thin wall part of the casting from producing cold barriers and failing to pour defects, the thin wall with a larger area should be placed on the lower part of the casting, or it should be placed on the side wall or inclined Location.