Lost Foam or evaporative-pattern casting is an innovative development in metal casting technology. The method was introduced at CFL in 1991.
The Process uses aluminium die tooling to produce expanded polystyrene patterns or forms. The final form is approx 97% Air / 3% Polstyrene. Forms are then glued into Clusters and eventually compacted into containers with Un-Bonded silica sand. Under casting the molten metal vaporises the form taking the shape of the original polystyrene pattern.
This process is advantageous for relatively complex shapes or castings that would normally require coring. It is also very dimensionally accurate, maintains a good surface finish, requires no draft and has no parting or join lines. As a result there is no flash and so very little fettling is required.
A variety of metals can be cast using evaporative pattern casting including;
Grey & SG Ductlile Iron, Ni Hards & Resists, High Chromium Irons, Non Ferrous metals such as aluminium & copper based alloys.
EPC – The main benefits
- Machining and fettling operations can be eliminated or significantly reduced
- Distinctive, high definition surface finish
- Long Tool Life
- Environmentally advantageous process
- Consistently close tolerance, “cast to size” or “near net shape” castings
- Unlimited design freedom & design for assembly:
- No need for coring
- Eliminates parting joint lines
- Permits minimal taper and undercuts
- Key ways, bolt holes, blind holes and inserts can be accommodated “as Cast”