Lost Wax Versus foamcast Lost Foam Metal Casting Technology
|Lost Wax Process
|Foamcast Lost Foam Metal Casting Technology
|Composition of Pattern
|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
|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
|No required, pouring is possible at room temperature of ceramic shell.
|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. 5-10mm depending on the size of component.
|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.