Shell Mould Castings
Shell moulding forms a thin, resin-bonded sand shell over a heated metal pattern, giving castings with better accuracy and surface finish than green-sand casting. It suits small to medium iron and steel parts in medium to high volumes.
What it is
Resin-coated sand is dropped onto a heated metal pattern; the resin cures into a rigid shell a few millimetres thick. Two shell halves are joined, metal is poured, and the thin shell breaks away easily.
The process gives consistent dimensions, fine detail and smooth surfaces, reducing machining compared with conventional sand casting.
Typical applications
- Crankshafts and camshafts
- Gear blanks and small housings
- Valve bodies and fittings
- Brake and hydraulic components
- Cores for complex castings
Suitable materials
- Grey and ductile iron
- Carbon and alloy steel
- Aluminium and copper alloys
Points to consider
- Metal patterns cost more than wooden patterns but last for long runs.
- Good choice between green sand and investment casting on accuracy and cost.
- Machining allowance is lower than green sand.
- Best for smaller parts in repeat volumes.
Frequently asked questions
What are the advantages of shell moulding?
Better accuracy and surface finish than green sand, thinner machining allowance and good repeatability for small to medium parts.
Is shell moulding expensive?
Pattern and resin costs are higher than green sand, but savings in machining and consistency make it economical at medium to high volume.
Which parts suit shell moulding?
Small to medium iron and steel parts such as gear blanks, crankshafts, valve bodies and hydraulic components.