Forming Techniques

Question 0

Advantages of blow moulding

Answer 0

Intricate shapes can be formed, can produce hollow shapes with thin walls to reduce weight and material costs. Ideal of mass production-low unit cost for each moulding

Question 1

Explain the blow moulding process

Answer 1

A hollow thermoplastic tube (to parison) is extruded between a split mould and clamped at both ends. Hot air is blown into the parison, which expands to take the shape of the mould, including any relief details, screw threads and undercut features.

Question 2

Disadvantages of blow moulding

Answer 2

High initial set up costs as mould expensive to develop and produce

Question 3

Polymers used on blow moulding

Answer 3

HDPE LDPE pet pp ps PVC

Question 4

Applications of blow moulding

Answer 4

Plastic bottles and controls of all sizes and shapes , fizzy stinks bottles and shampoo bottles

Question 5

Explain the injection moulding process

Answer 5

This process makes use of high cost mould that is injected with a liquid polymer made by heating thermoplastic granules. Once the polymer cools and solidifies the formed product is ejected.

Question 6

Advantages of injection moulding

Answer 6

Ideal for mass production - low unfit cost for each moulding for hight volumes. Precision moulding - high quality surface finish or texture can be added to the mould

Question 7

Disadvantages of injection moulding

Answer 7

Hight initial set up costs a mould expensive to develop and produce

Question 8

Polymers used on injection moulding

Answer 8

Nylon abs ps HDPE pp

Question 9

Applications of injection moulding

Answer 9

Casings for electronic products, containers for storage and packaging

Question 10

Explain vacuum forming

Answer 10

A thermoplastic sheet is clamped and heated, blown an stretched. Air is sucked out Of the vacuum machine to pull the softens sheet over a mould pushed up from below. Once the polymer has cooled it solidifies and cold air is blown between the mould and thermoplastic sheet to release the formed product.

Question 11

Advantages of vacuum forming

Answer 11

Ideal for batch production - inexpensive. Relatively easy to make moulds that can be modified.

Question 12

Disadvantages of vacuum forming

Answer 12

Moulds need to be accurate to prevent webbing from occur of. Large amounts of waste material produced

Question 13

Polymers used in vacuum forming

Answer 13

Acrylic hips PVC

Question 14

Application of vacuum forming

Answer 14

chocolate box trays, yogurt pots and blister packs etc