Plastics Processes: Sheet Moulding Compund (SMC)

Description of the compression moulding process used to mould Sheet Moulding Compound (SMC)

Materials used for compression moulding are either in the form of a dough-like substance or in sheet form.

Both forms are composed of resin, chopped glass fibres, a catalyst and a release agent.

Sheet Moulding Compound (SMC) is in the form of a plastic sheet that has not been cured, i.e. finally hardened. 

Shaping of SMC is achieved by using a compression moulding machine consisting of a "plug" and "yoke".

To mould the plastic into shape, a sheet of Sheet Moulding Compound (SMC) material is placed between the heated plug and yoke of a compression moulding machine. 

As the plug is lowered into the yoke, it squashes the SMC and forces it to take up the shape of the space between the plug and yoke. 

Heat from the compression moulding machine cures and hardens the plastic. When the SMC has cured and hardened sufficiently, the plastic moulded product is ejected from the mould.

Click on the link to view an animation of the compression moulding process using Dough Moulding Compound (DMC).

Learn about Plastics

Multimedia Design and Technology Education uses animations and supporting technology notes to teach about plastics and plastics processes.

Animations describe plastics processes in probably the most clear way possible, making plastics processes easy to understand, learn and remember.

All the plastics processing technology notes and animations can be found in the plastics section of our Key Stage 3 Design and technology software and in the Plastics Notes and Animations software package.

Click on a link below to view animations of plastics processes.

• Line Bending
• Expanded Polystyrene
• Injection Moulding
• Extrusion Blow Moulding
• Blown Film
• GRP
• Resin Transfer
• Pultrusion Process
• Moulding DMC

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Together, the KS3 Design and Technology and our original KS4 Design and Resistant Materials Technology software make a very useful and economical D&T teaching and learning package, giving students and teachers D&T information, exercises and tests.

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