Lost Wax Versus foamcast Lost Foam Metal Casting Technology
| Property | Lost Wax Process | Foamcast Lost Foam 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. |