1.4 Metal redistribution and casting

Question 1

What are the 5 types of metal redistribution and casting

Answer 1

Sand casting, Investment casting, gravity die casting, high pressure die casting, low temperature pewter casting

Question 2

What is the volume of production of sand casting

Answer 2

One off and batch production

Question 3

What metal casting process could create cast clamps, vices, benches, drain covers and post boxes

Answer 3

sand casting

Question 3

Is the surface finish with sand casting good?

Answer 3

No due to the sand texture

Question 4

What are the steps for sand casting

Answer 4

1. Half of a pattern is placed on a board inside one half of a moulding box(drag) which is turned upside down. The drag is carefully filled and packed with sand and the top is smoothed off
2. The drag is turned over and the second half of the moulding box(cope) is fitted. The second half of the pattern is aligned with the first half and tapered wooden sprue pins are placed either side of the pattern
3. Sand is carefully filled and packed around the pins and pattern. A pouring basin is cut into the sand
4. The sprue pins are carefully removed to leave “runner” and “riser” channels and the cope is lifted from the drag so the pattern can be removed. Channels are then cut into the sand to join the runner and risers to the casting cavity, before the cope is released
5. Sand is porous to allow gases to escape but sometimes vent holes are also created.
6. Molten metal is carefully poured into the pouring basin from where it flows down the runner filling the casting cavity and exiting up the riser channels and any vents
7. When cool the casting is removed from the sand and the excess metal is cut off and the casting is machined

Question 5

What metal casting process could create engine components

Answer 5

gravity die casting

Question 6

What metal casting process could create jewellery, hip replacements joints, propellers

Answer 6

investment casting

Question 7

What metal casting process could create figurines, toy cars, pencil sharpeners and engine housings

Answer 7

high pressure die casting

Question 8

What metal casting process could create decorative components

Answer 8

low temperature pewter casting

Question 9

What metals are gravity die casting used on

Answer 9

Non ferrous metals e.g. aluminium or zinc based alloys

Question 10

What are the steps for investment casting

Answer 10

1. A wax pattern is made
2. When several items are to be cast a wax “tree” is produced with a sprue and runners
3. The wax tree is dipped in a ceramic slurry
4. The wax tree is coated in sand
5. The wax is melted out of the ceramic mould
6. Molten metal is poured into a preheated mould
7. The mould is allowed to cool
8. The castings are broken out of the ceramic mould and the sprue and runners are cut away

Question 11

What is the volume of production of investment casting

Answer 11

Batch production

Question 12

What is the volume of production of gravity die casting

Answer 12

Very large batch and mass production

Question 13

What is the process of gravity die casting

Answer 13

Non ferrous metals e.g. aluminium or zinc based alloys, are poured into 2 part tool steel dies/moulds.

Question 14

What is the volume of prodcution of high pressure die casting

Answer 14

Mass production

Question 15

What is the process in high pressure die casting

Answer 15

Non ferrous alloys are injected into complex tool steel dies/moulds

Question 16

What metals are use high pressure die casting used on

Answer 16

Non ferrous alloys

Question 17

What metals are used in cold high pressure die casting and hot

Answer 17

Cold - zinc alloys, hot - aluminium alloys

Question 18

What is the process of tow temp pewter casting

Answer 18

A tin alloy(pewter), with a low melting point, is cast into a MDF mould.

Question 19

What is the volume of production of low temperature pewter casting

Answer 19

One-off or batch production