Lost foam casting was invented in the early fifties by Canadian sculptor Armand Vaillancourt. Public recognition of the benefits of SMD by General Motors in the mid-1980s when it announced its new car line, Saturn, SMD would be used for production of all engine blocks, cylinder heads, crankshafts, differential carriers, and referrals.
The process is advantageous solutions for the complex castings regularly require cores. It is also dimensionally accurate, maintains excellent surface finish, requires no draft, and no parting lines so no flash made. The sand can un-band ofbe much simpler to maintain than green sand and resin bonded sand systems. Lost foam is generally more economical than investment casting because it involves fewer steps. Risers not usually required because of the nature of the process; because the molten metal vaporizes the first metal foam into the mold cools faster than the rest, leaving the natural directional solidification. Foam is easy to manipulate, carve and glue, because of their unique properties. The flexibility of SMD often allows for consolidation of parts into one central part; Other forming processes would require the production of one or more parts to put together. The two main drawbacks that pattern can be high costs for low volume applications and patterns easily damaged or distorted due to low strength.If die used to create the patterns that large initial cost.
Popular cast metal include cast irons, aluminum alloys, steels and nickel alloys; often stainless steels and cast copper alloys as well. The size ranges from 0.5 kg (£ 1.1) a few tons (tonnes). The minimum wall thickness of 2.5 mm (0.098 in) and there is no upper limit. Typical surface finishes are 2.5 to 25 m (100-1000 μin) tolerance is ± 0.005 mm linear RMS.Typical / mm (0.005 in / in).