The main differences between lost foam casting and investment casting are the process, characteristics and application scope.
Process
Lost foam casting: Use a foam model, and the model will gasify and disappear during pouring. The main processes include making patterns, hanging paint, dry sand molding, pouring and sand removal.
Investment casting: Use wax molds to make shell molds, and pour after dewaxing. The main processes include wax mold manufacturing, wax mold assembly, shell manufacturing (dewaxing), sand filling pouring and sand removal.
| Comparison items | Lost foam casting | Investment casting |
| Model material | Foam (lightweight, easy to process) | Wax (high precision, fusible) |
| Casting material | Dry sand (no binder, good air permeability) | Ceramic shell (multi-layer refractory material) |
| Surface accuracy | Higher (Ra 6.3~12.5 μm) | Very high (Ra 1.6~6.3 μm) |
| Dimensional accuracy | Higher (CT8~10 level) | Very high (CT4~6 level) |
| Minimum wall thickness | Usually ≥2mm | Up to 0.5mm |
| Applicable metal | Cast iron, cast steel, aluminum alloy, etc. | High melting point alloys (stainless steel, titanium alloy, high temperature alloy) |
| Suitable part size | Small to large (up to several tons) | Small to medium (generally <50kg) |
| Production cycle | Shorter (no need for complex shell) | Long (shell production time-consuming) |
| Mold cost | Short (foam model is easy to process) | High (wax model + multi-layer shell) |
| Environmental protection | Foam gasification may produce gas pollution | Wax can be recycled, but ceramic shell processing is complicated |
Features
Lost foam casting:
Advantages: No need for parting/mold removal, simplified process; suitable for large-scale production, low cost; rough surface.
Disadvantages: Foam combustion may produce gas defects; suitable for medium and large complex castings.
Investment casting:
Advantages: High precision, smooth surface, suitable for high-precision complex parts; can cast thin-walled parts.
Disadvantages: Complex process, long cycle, poor applicability for small batches.
Application scope
Lost foam casting: Suitable for mass production of automobile engine cylinder blocks, machine tool parts, valve housings, etc.
Investment casting: suitable for high-precision and complex parts such as aerospace turbine blades, medical equipment, and jewelry.
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