Manufacturing processes

Question 1

What are the signs which show which manufacturing process was used to make a product?

Answer 1

Injection moulding - Witness marks from ejector pins
Blow moulding - There will be a seam where the two halves come together
Vacuum forming - The product must be removable from a mould so there mustn’t be any undercuts
Rotational moulding - The product must be hollow
Extrusion - A prism is made so if it is cut the same shape will show throughout it
Compression moulding - Thermosets are used
Calendaring - Makes a very thin film
Line bending - The product will be bent at a straight
line

Question 2

What is the process of injection moulding?

Answer 2

1) Granular thermoplastic flows down a hopper
2) The plastic is then moved by an Archimedean screw along a heating chamber
3) Once the granules melt it is pushed into a mould by a hydraulic ram powered by a motor
4) Once enough plastic has been injected into the mould, the mould is cooled to harden the plastic
5) The mould is then opened and the product is removed via ejector pins

Question 3

What is the process of extrusion?

Answer 3

1) Granular plastic is held in a hopper
2) It is moved by an Archimedean screw along a heating chamber
3) Once the polymer is melted it is pushed through a die mould which forms the shape of the extrusion
4) As there is no hydraulic ram in this process, the molten plastic can be fed through the die continuously
(The die is the mould that the plastic goes through)

Question 4

What is the process of vacuum forming?

Answer 4

1) The HIPS is heated
2) Once hot, the solid former is pressed into the HIPS from a rising bed
3) The vacuum is turned on, removing all the air from around the former
4) The HIPS takes the form of the solid former