Expendable pattern casting process is also called as lost foam casting process, which is adapted to cast steel, cast iron, cast aluminum and other metal castings, and large, medium and small castings of different structures and a variety of materials.
Characters of EPC
Expendable pattern casting process uses dry sand to mold and duplicate the prototype. The geometry of castings is of high precision, and there is no flash, burrs, cold shut, and the surface finish is close to the precision casting. The metal castings cast by expendable pattern casting equipment have stable internal structure and the blisters, air space, shrinkage and other casting defects are ruled out. This process makes full use of the idea of environmental protection, and the entire production process does no damage to the environment.
Expendable pattern casting is a new precise forming process of almost non-margin. This process does not need to take the mold, it has no parting and no sand core, thus the castings have no flash, burrs and taper angle, and the size error caused by core portfolio is also reduced, which can significantly reduce the machining costs, and compared with the traditional sand casting methods, the machining room can be reduced by 40 % to 50%.
Shortcomings of EPC
Like other casting process, expendable pattern casting also has its shortcomings and limitations, not all metal castings are suitable for expendable pattern casting (EPC) process, specific analysis should be carried out. Whether to adopt this technology is mainly based on the following factors.
1. Casting volume
The greater the volume is, the more substantial economic benefits will be.
2. Casting materials
The applicability of casting material is roughly in the following order (from good to bad): Grey iron - non-ferrous alloy - ordinary carbon steel - ductile iron - low carbon steel and alloy steel; With necessary preparations, the technical experiments and debugging cycle will not be too long.
3. Casting size
We should mainly consider the use scope of the equipment (such as tap sets, sand boxes).
4. Casting structure
The structure of metal castings is more complex, the more it can reflect the superiority of EPC technology and its economic benefits. For the structure of a narrow cavity channel and sandwich case, a pre-experiment is required before the use of EPC, and then it can be put into production.