Manufacturing processes (polymer)

Question 1

Wastage (only for sheets of polymer)

Answer 1

Chinagraph pencil to mark out line and use file
Coping saws. Fret saws. Band saws
Laser cut- acrylic
Holes drilled - portable driller / pedestal drill

Question 2

Additive

Answer 2

Adhesive - solvent cement (it dissolves surface of polymer so they can mix/combine with another part)

Heat- melt two edges together

Question 3

Deforming and reforming

Answer 3

Line bending - for simple bends

Moulding - vacuum forming

Question 4

Vacuum forming, Moulding (deforming and reforming method)

Answer 4

Vacuum forming used to mould thin thermoplastic polymer sheet over mould
Mould and sheet placed in heater
Atmospheric pressure pushes heated thermoplastic polymer sheet over mould, air is sucked out
Moulded sheet produced

Question 5

Large scale processes

Answer 5

Injection moulding- complex 3D shapes
Compression moulding- simple 3D shapes thermoset
Extrusion- tubes or sections 
Blow moulding- hollow products
Vacuum forming - open

Question 6

Injection moulding process

4 compelx shapes 3d

Answer 6

• Thermopolymer granules in hopper drop into machine
• motor spins archimedean screw
• rotating screw forces granules trhoguh heared section
• heats up thermopolymer to liquid as it is moved
• liquid forced into mould by screw
• pressure maintained on mould until it cools down
• open mould and finished product taken out

Question 7

Extrusion process- tubes or section

Answer 7

• thermopolymer granules in hopper drop onto screw
• motor turns screw
• pushes granules through heated section
• granules melt into liquid and its forced through a die (die shape determines tube shape) in a continuous stream
• Forming a long tube shape/section
• Is cooled and forms solid shape

Question 8

Blow moulding process - hllw shape

Answer 8

• polymer granules in hopper
• motor turns screw thread, feeds granules through heated section
• granules melt into liquid
• granules ftoces into mould
• air forced into mould which forces the polymer to the sides of mould, giving a hollow shape
• cooled and removed

Question 9

Compression moulding - simple 3d shape

Answer 9

Thermoset polymers
Mould heated
Slug (piece of polymer placed into mould and watms up)
Hydraulic press moves down when polymer is hot enough
Polymer compressed into mould shape
Final product removed

Question 10

What is a draft edge in vacuum forming

Answer 10

Is a tapered angle/slant on a former

So the product is easy to remove from the mould after it is formed and cooled

Question 11

Nesting

Answer 11

Laying it out so every part of the material is used as much as possible for the shapes being cut, theres little waste, to save money

Question 12

Line bending

Answer 12

Acrylic sheets and other thermoplastics
It is fold/bent on a strip heater
When plastic becomes flexible it is placed in a jig and a square section is then pressed against the plastic to hold it in position as it cools

Question 13

Polymer finishes

Answer 13

Wet and dry paper-used to remove any marks from polymer
Vinyl- vinyl cutrers used to cut sheets of vinyl for signs on products. Cutter moves along vector paths.
Painting
Spray painting- abrade surface with wire wool, clean with water and detergent, spray with primer paint and finish witb top coat (spray can for small, spray gun attached to compressor for large)
Polish- file edge, wet and dry peper, polishing machine/ rotating mop
Laser cutter etching - pattern cut into surface

Question 14

Rotational moulding

Answer 14

Uses mould that is rotated continuously, containing heated thermoplastic powder
Alternative to injection moulding or blow moulding
-mould split apart and thermoplastic poured in
-heat applied while mould is rotated
-plastic is thrown outwards to inner surface of mould
-on cooling the mould is opened up and product ejected