The position of castings in casting during pouring affects the quality of precision castings, the precision of size and the difficulty of molding process.
Selection principle of pouring position:
1. Precision castings of the important processing surface or the main processing surface facing down or located on the side: pouring, metal liquid gas, slag and cast sand particles will float, may make the upper part of the castings appear stomata, slag, sand eyes and other defects, and the bottom of the casting defects, the organization is more dense. A. The pouring position of the machine bed should be facing down the rail to ensure the quality of the important working surface.
Its circumference surface quality requirements are high, the use of vertical pouring scheme, can make the circumference surface on the side, to ensure uniform quality and consistency.
2. Precision casting large plane facing down or tilt pouring: because the hot metal liquid during pouring has a strong thermal radiation on the upper part of the casting, causing the top sand type expansion arch or even cracking, so that the large plane appears sand clamping, sand eyes and other defects.
Large plane facing down or the use of tilt pouring method can avoid large plane production casting defects.
3. Thin walls of precision castings face down, side or tilt: in order to prevent cold separation of the thin-walled parts of the castings, do not pour defects, the larger wall should be placed in the lower part of the castings, or put it in the side wall or tilt position.
4. Most of the thickness of the precision castings should be placed at the top or on the side of the fractal surface the main purpose is to facilitate the placement of the riser in the thick place for shrinkage.
