Lost Wax Process Versus Foamcast

Lost Wax Process Versus foamcast® Lost Foam Metal Casting Technology.

Property	Lost Wax Process	foamcast® Metal Casting Technology
Composition of Pattern	Microcrystalline Wax	Expanded Polystyrene (EPS)
Density of Material used for pattern	Density of Microcrystalline Wax Patterns - 795 kgs./m³, resulting in heavy delicate patterns.	Density of Expanded Polystyrene Patterns - 42 kgs./m³ sufficient for strong, sturdy, dimensionally accurate and light patterns.
Maximum Size of Cast Part	Approx. 200-300mm	No limitation of size for cast part as EPS Pattern can be molded in sections and finally assembled to form a single pattern.
Maximum Weight of Cast Part	Well Below 125 kgs.	No limitation of weight of cast part.
Rejection of Shell during process	The ceramic shell has a tendency to crack during the autoclave process due to the expansion of Wax	The ceramic shell does not crack during the burn-off process as EPS does not expand but evaporates/melts.
Pre-Heating of Ceramic Shell	Required	No required, pouring is possible at room temperature of ceramic shell.
Methoding	Difficult and has limitations in addition to the problem of riser backfilling.	Flexible, risers are simply glued on the pattern to suit the methoding. Furthermore the feeding ability of riser is improved with the use of exothermic sleeves.
Ceramic Shell Thickness	Approx. 10-15mm	Approx. 5-10mm depending on the size of component.
Pattern/Casting Prototyping	Difficult	Easily possible as EPS foam can be machined and assembled to form patterns
Effect of atmospheric heat on patterns	Possibility of Wax pattern to warp or bend.	No effect on EPS pattern once cooled in the molding tool.

For a comparion of foamcast® - lost foam casting process with Green Sand Process please click here

Note: Non-proprietary terms that have been used to describe similar processes include: cavityless casting, evaporative foam casting, foam vaporization casting, lost pattern casting, the castral process, expanded polystyrene molding, EPC, Evaporative Pattern Casting, LFT, Lost Foam Technology, Expendable Pattern Casting, lostfoam, shellfoamcast, etc.