Moulding, Forming And Joining Processes For Polymers

Question 1

Injection moulding

Answer 1

Polymer is melted down and injected into a mould via the archemedies screw and hydronic ram.

For metals this is called high pressure die casting

Question 2

Blow moulding

Answer 2

This is the processes where the polymer is inserted into the machines as a PARISON (hollow polymer tube. Air is then pumped in with the assurance of heat to expand the polymer to shape of the mould.

Question 3

Rotational moulding

Answer 3

This process the polymer is inserted into the mould as a semi liquid slug.
The mould is the closed and the mould is heated and spun in all directions to clover all walls. This spinning is repeated whilst mould cools.

Question 4

Thermoforming/ Vacuum forming

Answer 4

Material is heated just above softening point and then held securely between two mould halves with a vacuum applied at the same time to gain all required detail.

Question 5

Extrusion

Answer 5

Extrusion is when polymers are heated and forced through a die via a rotating screw to create a uniform cross sectional shape

Question 6

Calendaring

Answer 6

The pre mixed polymer will be heated slightly and passed through many rollers to stretch the material until it reaches the desired thickness

Question 7

Line Bending

Answer 7

A heat strip is used to heat the polymer in a specific point which is the bent over jig

Question 8

Compression moulding

Answer 8

A slug of material (polymer or metal) is placed into the bottom half of the mould. The top half is the clamped tightly to squeeze the material all around the mould and them removed.