Shell Mould Casting-
If the mould is made like a shell called as shell mould casting.In this article,all the important points are discussed and underlined which can be helpful to you in any examination.Shell means thin mould or Hollow mould.The material used for mould is a Phenolic resin (Thermosetting Plastic) has the viscosity of (Dynamic Viscosity equal to 1500 to 2000 Centipoise).
- Dip the pattern into phenolic resin for 1 to 2 minutes.
- Take the pattern out.
- Keep it in a furnace at 250 degrees to 300 degree centigrade for 1 to 2 minutes.
- Take out the pattern from furnace
- Remove the top layer of phenolic resin.
- As it is the phenolic resin will have higher brittleness but to increase the strength and reduce the Brittleness,the sand particles are to be added to the phenolic resin.
Shell Mould Casting-Features,Ceramic Slurry,Applications,Advantages&Disadvantages:
In Shell mouldcasting,if ceramic slurry is used as a mould material in place of phenolic resin it is called as ceramic moulding operation.
Features of Shell mould casting:
- Because of lower thickness of the mould, weight of the world is less.hence handling will be easier.
- Because the time taken for producing a mould is less,the production rate is high.
- Because the activities used for mould making are standard activities,the process can be mechanized are automated.
- As there is the lower porosity property of phenolic resin mould,the escape of air or gases can be passed easily through Risers.
- This method is used for producing symmetrical and circular shape of castings only.
Applications of Shell Mould Casting:
It is used for producing cylinders and cylinder heads of
- IC engines
- Gear blanks
- bevel gears etc.
Advantages of Shell Mould Casting:
- Thin and complex sections undergo casting very easily.
- High dimension,accuracy and good surface finish is one of the advantage of shell mould casting.
- No further machining required.
- It can be operate by an semi skilled operator.
- Easily automated.
Disadvantages of Shell Mould Casting:
- For larger casting components,Special metal pattern required and which makes it expensive.
- Shell moulds are less permeable compare to green sand mould.
- Size and weight limitation.
- It is not suitable for small batch production.
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