shaping techniques

Question 1

features of milling machines

Answer 1

• removes material one thin layer at a time
• machines can be set to a particular cutting speed and depth
• can be used to make a surface absolutely flat and can produce a very accurate finish

Question 2

features of Lathes

Answer 2

• come in two types ; wood lathes and engineers lathes
• used to ‘turn’ materials

Question 3

features of 3D printing

Answer 3

• additive
• works by printing layers of molten plastic, power or wax until the full 3D shape has been formed
• can design your ideas on screen using various softwares packages

Question 4

what does press forming involve

Answer 4

• involves pressing metal sheets between two moulds with a large amount of force
• the metal sheets to be pressed are often annealed, as it makes them more malleable

Question 5

how does press forming work

Answer 5

1. a sheet of metal is placed between two moulds (a punch and a die)
2. a hydraulic press moves the punch down and a large force is applied to the metal sheet
3. this pushes the sheet of metal into the die, producing the required shape

Question 6

what does casting involve

Answer 6

• molten material being poured into a hollow mould
• material is then left to cook and solidify before being separated from the mould

Question 7

features of die casting

Answer 7

• used to mould metals and thermoforming plastics

Question 8

outline the process of die casting

Answer 8

• material is melted and poured into a mould that’s the shape of the product
• it’s then allowed to cool. once it’s solidified, it can be removed from the mould
• some plastic resins can be cold poured into moulds and garden through a chemical reaction
• when the products removed, it may need to be trimmed to remove any excess material

Question 9

ways materials can be bent

Answer 9

• sheet metal folder - to shape sheet metals such as aluminium and tin
• laminating - to bend wood
• line bending - ideal for use with acrylic

Question 10

outline the process of vacuum forming

Answer 10

• a mould is put onto the vacuum bed
• thermoforming plastics are clamped above the vacuum bed and heated until they go soft
• the vacuum bed is lifted close to the heated plastic
• air is sucked out from under the plastic. the air pressure from outside the mould then forces the plastic onto the mould
• the moulded plastic is cooled and the vacuum bed lowered
• the cold plastic is rigid and holds its new shape

Question 11

what does blow moulding involve

Answer 11

• a tube of softened plastic is inserted into a solid mould
• air is then injected which forces the plastic to expand to the shape of the mould
• this methods often used to produce bottles and containers

Question 12

features of injection moulding

Answer 12

• similar to casting, but the molten material is forced into a closed mould under pressure
• these moulds are often made from tool steel, and the plastic is often melted using built in heaters
• can be used to make things like plastic buckets and watering cans

Question 13

features of extrusion

Answer 13

• similar to injection moulding
• used for thermoforming plastics and some metals
• material is melted and forced under pressure through a die
• produces long and continuous strips
• used for products such as plastic covered wire, plastic and aluminium window frames

Question 14

features of drape forming

Answer 14

• sheet of thermoforming plastic is heated till it softens
• soften sheets takes the shape of the mould that it’s placed in
• once it’s cooled it will stay that shape

Question 15

examples of glues (adhesives)

Answer 15

• polyvinyl acetate (PVA) - used w wood, paper and card, dries slowly
• glue guns - good for modelling, used on woods and fabrics
• solvent cement - used on plastics, needs to be clamped while it sets
• epoxy resin and superglue - used on most materials but expensive

Question 16

features of soldering

Answer 16

• low temperature process
• involves melting solder onto components to be joined
• uses a soldering iron

Question 17

features of brazing

Answer 17

• high temp process
• stronger than soldering
• blow torch or gas brazing torch used

Question 18

features of welding

Answer 18

• strongest method of joining metal
• very high temp from a gas, torch, or electric arc welder, used to melt the edges of the joint

Question 19

what is solder made from

Answer 19

tin and other metals