Common casting methods for precision casting
The more commonly used in precision casting is investment casting, also known as lost wax casting: use appropriate investment material (such as paraffin) to make investment patterns; repeat the application of refractory coatings and refractory sand on the investment pattern, harden the shell and Dry; melt the internal melting mold to obtain a cavity; roast the mold shell to obtain sufficient strength and burn away the remaining investment material; cast the required metal materials; solidify and cool, and clear the sand after dehulling, Thus, a high-precision finished product is obtained. According to product needs or heat treatment and cold processing and surface treatment. For example, sand casting, mass-production factories should create conditions to adopt technologically advanced modeling and core making methods. The production line of the old-fashioned shock or pressure molding machine is not high in productivity, the labor intensity of workers is high, the noise is high, and it is not suitable for mass production. It Lost wax casting should be gradually transformed. For small castings, horizontal parting or vertical parting can be used without box high pressure molding machine production line, solid molding production efficiency is high, and the floor area is also small; for middle pieces, various boxed high pressure molding machine production lines, gas Punching the molding line to meet the requirements of fast and high-precision molding production lines. The core making method can be selected: cold core box, hot core box, shell core and other efficient core making methods.
Medium-sized large-scale castings can be considered using resin self-hardening sand modeling and core making.
For heavy-duty castings produced in small batches, manual modeling is still an important method. Manual modeling can be flexible to meet various complex requirements, and does not require many process equipment. Water glass sand mold, VRH method water glass sand mold, organic ester water glass self-hardening sand mold, clay dry mold, resin self-hardening sand mold, and cement sand mold can be applied. For heavy-duty castings produced in a single piece, the Heat Resistant Steel Casting pit modeling method has low cost and put into production fast. Multi-box modeling and split-box modeling are more suitable for mass-produced or long-term production of shaped products. Although molds, sand boxes, etc. have high initial investment, they can be compensated by saving modeling man-hours and improving product quality.
Low-pressure casting, die-casting, centrifugal casting and other casting methods are only suitable for mass production due to the expensive equipment and molds.