Moulding

Moulding

Injection Moulding

Injection Moulding Gif

or

Injection Moulding Gif

Remember to add ejector pins to the mould

Uses any thermosoftening plastic, usually ABS

More information


Extrusion

extrusion Gif

Uses any thermosoftening plastic, usually ABS

 

 

Advantages of injection moulding/extrusion: Both can be automated, no surface finish required, can create complex shapes

Disadvantages: High initial cost, limited to just thermosoftening plastics


Blow Moulding

Blow moulding Blow moulding Blow moulding Blow moulding

The plastics normally used in this process are: polythene, PVC (thermosoftening/thermoplastics)

Advantages: Automated process, quick, very low cost

Disadvantages: Can only create thin & hollow products, can only use


Vacuum Forming

Vacuum forming

The plastic sheet is removed from the vacuum former. The sheet has the shape of the former pressed into its surface.

Vacuum forming

The excess plastic is trimmed

Vacuum forming

Compression Moulding

Compression Moulding

1) A preformed slug (compressed plastic powder) is placed in the lower die/bottom mould.

2) The mould is heated so that the plastic becomes soft and malleable

3) The upper die/half of the mould is closed down onto the lower die/bottom mould, pressing the slug into the shape of the mould

4) The plastic goes into the shape and any excess plastic comes out the side of the pattern. The upper mould is moved up again and the product is removed

5) The excess plastic is trimmed off. Uses thermosetting plastics that soften when heated and cannot be reshaped

Common thermosetting plastics used are: Urea Formaldehyde, PP (Polypropylene), Melamine formaldehyde


GRP Moulding

GRP Moulding

Advantages: GRP has a high strength to weight ratio, process doesn't require expensive equipment, easy to do, doesn't require skilled worker, doesn't require further surface finishing

Disadvantages: Takes a long time to cure/harden, material (fibreglass) is expensive, requires trimming, not recyclable, expensive


Carbon Fibre

Carbon fibre is woven into a textile material. Epoxy resin is added and allowed to cure.

Carbon fibre can be made into a shape using a similar process to GRP

The woven carbon fibre is placed on top of the mould and epoxy resin is applied

More layers can be added if needed

Can cure naturally or be baked in an oven at 170 degrees celsius. This makes it much harder and stronger

Advantages: It is much stronger than GRP. Doesn't require further surface finishing

Disadvantages: It is more expensive than GRP. It also isn't recyclable, requires trimming in most cases