Manipulating And Joining (plastics)

Question 1

Marking out

Answer 1

• chinagraph pencil
• a non permanent marker
• a permanent marker

Question 2

Wastage

Answer 2

• cutting
• milling and turning
• multi axis machines
• drilling

Question 3

Cutting

Answer 3

• scissors
• craft knives
• coping saw
• band saw
• scroll saw
• laser cutter

Question 4

Milling and turning

Answer 4

Can be used to cut slots and grooves in blocks of polymer

• the workpiece is fixed to a table that can move backwards and forewords, up and down
• CNC controlled milking machines can be use to cut more complex shapes
• centre lathes can be used o make round components
• CNC lathes can be used to cut more complex shapes

Question 5

Multi axis machines

Answer 5

• they can move in four or more ways in order to manufacture complex parts
• they ca; be considered a combination of a lathe and a milling machine

Question 6

Drilling

Answer 6

• polymers can be drilled
• drills for polymers Generally have a shallower cutting angle and the speed of the drill is reduced
• when drilling a polymer you should put bits of wood on top and on the underside of the polymer to prevent the work from moving and chipping

Question 7

Types of addition

Answer 7

• adhesion
• heat welding
• mechanical fixing

Question 8

Adhesion

Answer 8

• evo stik can be used to join two thin polymer sheets to other materials
• epoxy resin can be used to glue some polymers together once the surfaces have been roughened
• polystyrene cement is awe to join modelling kits such as Air fix kits
• tendon is a solvent based adhesive to join acrylic
• DCM is a thinner version of tendon
• double sided tape can be used as a semi permanent method of joining two polymers together

Question 9

Heat welding

Answer 9

The hot air welding tool heats up the material to be joined and feeds a thin wire polymer into the area to be joined

Question 10

Mechanical fixings

Answer 10

Polymers can be joined using a wide range of mechanical fixings for machine screws, bolts, self taping screws, rivets and clips

Question 11

Common methods of deforming and reforming polymers

Answer 11

• line bending
• drape forming
• press moulding
• vacuum forming

Question 12

Line bending

Answer 12

A process used to create simple bends in polymer sheets such as acrylic. This is created by heating a sheet material along a line with a strip heater until it softens. It is the. Folded and held in place until is cools and hardens.

Question 13

Drape forming

Answer 13

A process used to create a large curve or bend. This is created by heating a polymer sheet in an oven until it softens, then it is draped over a former and a piece of cloth is pulled tightly across it to hold it in shapes until the polymer has cooled.

Question 14

Press moulding

Answer 14

A process used to produce more complex shapes such as trays or dishes in thin polymer sheet. Press moulding uses two part formers called a yoke (the upper piece) and the plug (the bottom piece). The polymer sheet is heated in the oven until it softens then it’s placed over the plug and covered by the yoke. Both parts of the former are clamped until the polymer has cooled down.

Question 15

Vacuum forming

Answer 15

A process used to produce more complex large shapes, such as packaging and baths, from polymer sheets. Vacuum forming is done by clamping a polymer sheet in position and heated until it softens. Below the plastic sheet is a mould that is raised and the air between the mould and the plastic sheet is sucked out by a pump. Once the material has cooled, it is removed from the machine.