Injection Moulding (thermoplastics)

Question 1

Define injection moulding

Answer 1

Injection moulding forces soft heated plastic into a split mould to make any shape

Question 2

Is injection moulding capable of producing complex products and/or at high volumes?

Answer 2

Injection products: complex or high volume

Question 3

List some examples of products produced by this method

Answer 3

CDs, DVDs, packaging, containers, toys, bottle caps, chairs, gears, plastic cutlery, Lego bricks, buttons, toothbrushes, medical devices, car bumpers, switches

Question 4

What thermoplastics are used in the manufacturing process?

Answer 4

ABS, PVC, PE, PS, HIPS, PC, PP

Question 5

Explain the process of injection moulding in 5 steps

Answer 5

1. Thermoplastic pellets are loaded into the hopper.
2. The screw turns and compresses the pellets into soft plastic.
3. Heaters soften the plastic further.
4. The entire screw moves forward like a piston and injects the f=soft plastic into the cooled mould.
5. The two halves (dies) of the split mould are opened, and the moulded part is ejected.

Question 6

What must be labelled on a diagram for injection moulding? (14)

Answer 6

loading hopper, screw, molten plastic, split mould, finished product, die 1, die 2, heaters, pellets being compressed, granular thermoplastic, motor, lead screw, hydraulic system,