Investment casting is more commonly used in precision casting, also known as lost wax casting: the appropriate investment material (such as paraffin) is used to make the investment; the process of dip refractory coating and refractory sand on the investment, hardening the shell and Dry; dissolve the internal mold to obtain the cavity; roast the shell to obtain sufficient strength, and burn off the residual mold material; cast the required metal materials; solidify and cool, clear the sand after shell removal, Thereby obtaining high-precision finished products. According to product needs or heat treatment and cold processing and surface treatment.
Mass production factories should create conditions to adopt technologically advanced modeling and core making methods. The production line of the old-style shock-type or shock-pressure molding machine is not high in productivity, the labor intensity of the workers is large, and the noise is large. It cannot adapt to the requirements of mass production and should be gradually reformed. For small castings, you can use a horizontal or vertical parting boxless high-pressure molding machine production line, the real molding production is high in efficiency, and the area is small; for middle parts, you can use a variety of boxed high-pressure molding machine production lines, gas The molding line is punched to meet the requirements of a fast and high-precision molding production line. The core making method can be selected: cold core box, hot core box, shell core and other efficient core making methods.
For medium-sized large-scale castings, resin self-hardening sand molding and core making can be considered.
For single-piece, small-batch production of heavy castings, manual molding is still an important method. Manual molding can adapt to various complex requirements and is relatively flexible, without requiring a lot of process equipment. Water glass sand type, VRH method water glass sand type, organic ester water glass self-hardening sand type, clay dry type, resin self-hardening sand type and cement sand type, etc .; for single-piece heavy castings, the pit molding method is low in cost and put into production fast. It is more appropriate to use multi-box molding and split-box molding for mass-produced or long-term stereotyped products. Although molds, sand boxes, etc. have begun to invest heavily, they can be compensated for saving molding time and improving product quality.
Low-pressure casting, die casting, centrifugal casting and other casting methods are only suitable for mass production because of the high cost of equipment and molds.