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Lost foam casting

Forming process in which molten material is poured on a polystyrene detail surrounded by a ceramic shell is immersed in the sand.

Beskrivning
Illustration of Lost foam casting

The process

A full scale model of polystyrene foam is manufactured and provided with inlet, riser pipes, valves and other details required to melt effectively to fill the part. The model is coated by spraying a ceramic slurry [1], which then solidifies.

The coated pattern is placed in a mold [2], which is filled with sand to provide an external support.

Melt is then poured into the inlet pipe and burns polystyrene foam element while it fills the void that occurs [3].

After the melt is solidified, the sand is removed and then ceramic shell now encloses the finished part [4].

Finally the ceramic shell and excess solid details are removed to expose the finished part.

Lost foam casting
Advantages and disadvantages
In comparison with alternative methods
Customizable for complex shapes
High dimensional accuracy
Requires no draft angle
Have no dividing line
Risers are usually not needed due to nature of the process
Better solidification process
Cheaper than lost wax casting
Cost of patterns can be high for small series production
Patterns can be easily damaged and distorted
Pattern has low strength
Only materials with low melting temperature can be used in this process