Investment materials refractory die and casting

Question 1

4 types of investment materials

Answer 1

dental plaster or stone
gypsum bonded
silica bonded
phosphate bonded

Question 2

what is dental plaster moulds used for

Answer 2

acrylic dentures

Question 3

what is gypsum bonded moulds used for

Answer 3

gold casting alloys

Question 4

what are silica bonded moulds used for

Answer 4

base metal casting alloys

Question 5

principal components of investment materials

Answer 5

binder
refractory material usually silica

Question 6

casting faults

Answer 6

finning and bubbling
incomplete casting
porosity in casting
over/ under sized casting

Question 7

what is refractory die used for?

Answer 7

CoCr frameworks
porcelain crowns

Question 8

what forms the refractory die?

Answer 8

phosphate bonded investments
refractory material usually silica

Question 9

melting temp?

Answer 9

> 1000 degrees

Question 10

3 mechanisms of investment expansion?

Answer 10

thermal
setting expansion of the binder
hygroscopic

Question 11

what is used for casting a melting alloy?

Answer 11

furnace

Question 12

what is used for forcing alloy into mould?

Answer 12

vacuum