Shaping

Question 1

basic steps of casting

Answer 1

1 - mould prepared
2 - raw material liquified
3 - liquid material poured into mould
4 - material allowed to harden
5 - cast part is removed from mould

Question 2

name of mould type that is broken up to remove the cast part

Answer 2

frangible mould

Question 3

name of mould type that is re-used to cast multiple parts

Answer 3

permanent mould

Question 4

advantages of sand casting

Answer 4

sand easily compacted into shape around pattern
sand tolerant of high temp (>1700 degC)
sand can be mixed with additives to improve moulding
sand is cheap and largely re-usable

Question 5

what allows die casting to achieve thinner castings than sand casting?

Answer 5

molten metal can be forced into the cavity under pressure which allows faster filling

Question 6

steps to investment / lost wax casting

Answer 6

wax patterns assembled on a ‘tree’
tree gets coated in ceramic slurry
coated tree is fired to harden the ceramic and melt away the wax
ceramic mould filled with molten metal
mould broken away after metal solidifies

Question 7

what is the parting plane?

Answer 7

plane along which mould is split to remove pattern or part

Question 8

which faces need to be drafted to facilitate removal from mould?

Answer 8

faces perpendicular to the parting plane

Question 9

the name of that little thingy that supports a core but is made of thin pieces of the casting material, you know?

Answer 9

chaplets

Question 10

features to avoid when designing a cast part

Answer 10

sharp corners and angles
thin features
large changes in area

Question 11

favorable features when designing cast parts

Answer 11

fillet radii of corners
draft angles
uniform thickness when possible

Question 12

it is better to fill a mould at the (thickest/thinnest) regions and from the (bottom/top) of the cavity

Answer 12

thickest ; bottom

Question 13

where should you add risers to your mould?

Answer 13

at gates or vents