Material Processes Flashcards
1
Q
Process of Injection moulding
A
- Plastic granules are fed into the hopper.
- The screw in the chamber below the hopper sends the granules forward.
- Heated jackets around the screw mel the polymer.
- The screw winds back and the hydraulic ram
- The mould is closed and sealed as the ra, forces the melted plastic into the mould.
- The plastic is allowed to cool and the halves of the mould release.
- The screw is released off.
2
Q
Process of Vaccum Forming
A
- The mould is placed into the former.
- A sheet of thermoplastic such as HIPS is clamped over the mould.
- The plastic is slowly heated to become soft.
- The former is raised as air is sucked out, drawing the plastic over the former to take its shape.
- The edges must be trimmed and finished.
3
Q
What process will blow moulding contain
A
Water bottles (unrecyclable ones you get from Tesco)
4
Q
What polymer process uses line bending
A
Anything that is formed into a shape.
5
Q
What polymer process contains extrusion
A
Something that is long (pause)
6
Q
What are the commercial processes for timbers
A
- Routing: use a router
- Turning: using a lathe
7
Q
Routing process
A
- The cutting blade on a router will spin at a high speed.
- Material is removed as the user moves the router over or through the timber, which is held securely
- A centre lathe on the other hand, holds the timber securely and spins this at high speed
- The cutting tool is controlled by the user and is moved into the timber to remove material
8
Q
Turning process
A
- A lathe works by spinning a piece of timber at speed.
- While the timber is turning, a wood-turning tool is pushed into the timber to change its shape.
- Some timber can be held in place by compressing it from end to end.
- This would allow a spindle or cylinder to be shaped.
- Another way to hold the timber is to screw it to a faceolate - the timber spins on the lathe, and this would allow a bowl to be turned.
9
Q
Three main methods of shaping metal
A
- Turning
- Milling
- Casting
10
Q
Process of turning
A
- Metal can be turned in a lathe, which can be hand operated or controlled via a computer on a CNC lathe.
- A lathe spins the work at high speed as a cutting tool is introduced to the metal to produce round and cylindrical shapes.
- Round pieces of metal are held in a lathe using a three-jaw chuck, and metal that is not round is held by a four-jaw chuck
11
Q
Process of milling
A
- Metal can be shaped using a milling machine - a tool to smooth surfaces or edges and for cutting grooves and profiles.
- Milling machines can work either horizontally or vertically - both machines can perform the same tasks; the main difference is the direction the cutting tool is held.
12
Q
Process of sand casting
A
- Former is made, usually by hand and is placed in the ‘green’ sand which is packed tightly around the former before it is removed
- Repeated on the other part of the mould
- Two holes are made in the sand, one for molten metal to be poured and the other for metal to come up and out the other side
- Once they are both ready, parting powder is applied to the sand and the two moulds are placed together, one on top of the other
- The molten metal is poured into the runner until it comes up to the riser when the cavity sand is full of metal.
13
Q
Extrusion process
A
- Granular plastic is held in a hopper
- It is moved by Archimedean screw along a heated tube, called the heating chamber
- Once the poly,er has been melted it is pushed through a die mould, which will form the shape of extrusion
- Because there is no hydraulic rammin the process, molten plastic can be fed through the die continuously
