Calculating The Quantities, Cost And Size (plastics)

Question 1

Quantity

Answer 1

The amount of material required to make a product

Question 2

Cost

Answer 2

Fixed costs- the cost of making tools and fitting them into a machine
Variable costs - the costs is making parts, including raw materials, about and energy

Question 3

Sizes

Answer 3

All polymers that are moulded by heat will shrink as the moulding cools. The finished size of the product must be kept within tolerance.

Question 4

How to predict shrinkage

Answer 4

Type of polymer
Thickness of walls
Mould temperatures
Pressure used on the moulding

Question 5

Tolerances and minimising waste

Answer 5

• designing the parts accurately
• minimising material by judging the correct wall thickness
• reducing the cycle time by designing moulds that allow parts to cool rapidly and be ejected
• reusing waste material by feeding excess material back into the moulding machines