Shell Molding

All the metals we see today are a product of the different kinds of casting. Casting is a very tedious process. You need to consider a lot of conditions in order to create the product. Even what metal will be used will be specific to a certain product you want to achieve.

So what is casting?

Casting – a process in which liquid metal is poured into a mold with hollow cavity of the desired shape

Casting is subdivided into 2 main categories:

Expendable

Non-expendable

I will be focusing on Shell Molding Casting

Shell Molding also known as Shell Mold Casting, Shell Process, Croning Process.

It is an expendable mold casting process that uses a resin covered sand to form the mold that will be used in the process.

also known as “Croning process”, this casting technique was invented and patented by J. Croning during World War II (1947)

The main components of this process

Shell – in shell mold casting, the mold is a thin-walled shell created from a mixture of sand and a thermosetting resin. The solidification of sand and resin creates a shell-like structure that can able to withstand a specific amount of heat.

Resin – a solid or highly viscous substance of plant or synthetic origin which can be converted into polymers. This is important because this is one of the ingredients that make the sade glued to each other creating the shell.

Thermosetting – property of plastics to strengthen when heated. Together with the resin and sand, this creates the hard shell mold.

Characteristics of Shell Molding

Finer sand is used compared to sand casting particularly uses metal patterns to produce a smooth finished and particularly applicable for steel castings under 20 lbs (small to medium parts) typically around 10 to 20 mm thickness of the mold. In manufacturing, a reusable pattern allows for higher production rates, while the disposable molds enable complex designs.

The Shell Molding Process

Sample Products of Shell Molding

Thank you for reading!

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