Vacuum forming plastics

Question 1

what is another name fro the pressing of heat-softened plastic sheet over a mould by means of atmospheric pressure?

Answer 1

VACUUM FORMING

Question 2

name something that is a commercial product that is vacuum formed.

Answer 2

Margarine containers

Question 3

Is it easy to make deep mouldings?

Answer 3

No but it’s useful for making several identical mouldings.

Question 4

name 3 things that all vacuum forming machines do

Answer 4

• enable a plastic sheet to be sealed temporarily on top of a vacuum chamber
• heat up the sheet
• cause a vacuum underneath the softened sheet to draw it down over a mould

Question 5

the plastic sheet (usually polystyrene) is clamped in a frame over the vacuum chamber. It rests on a ______ rubber sealing strip which is heat resistant.

Answer 5

SILICONE

Question 6

moulds are normally made of _____

Answer 6

wood

Question 7

what is an ideal material for making moulds?

Answer 7

MDF (medium density fibreboard)

Question 8

the vertical sides of your mould should be slightly angled so it can be easily withdrawn from the plastic sheet- this is called a ____ or ______

Answer 8

DRAFT

TAPER

Question 9

If your mould is too deep, excess plastic sheet will stick together at the corners. This problem is called…

Answer 9

WEBBING

Question 10

The surfaces of your mould must be smoothed with fine _________

Answer 10

glasspaper

Question 11

you should also do something to the base of the mould so that pockets of air are not trapped when he sheet forms

Answer 11

drill small holes in the base