|
PROCESS
DEFINED
:
|
| Casting
made by pouring metal under a gravity head
into molds made of gypsum with strengthening & setting agents added. |
|
MATERIALS
: |
| any
nonferrous material having a melting point
of less than 2000°f, except magnesium in
large sizes. |
|
RATE
OF PRODUCTION
: |
| low,
not a high production process. |
|
SIZE
& WEIGHT OF PARTS
: |
| relatively
small. |
|
STRENGTH
OF PARTS
: |
| equal
to sand castings. |
|
WALL
THICKNESS
: |
| not
as thin as lead, tin or zinc die castings,
but sometimes equal to die castings of
aluminum magnesium & brass |
|
COMPLEX
ITY
: |
| usually
not so complex as die castings or permanent
mold castings. |
|
|
|
|
|
PRECISION
INVESTMENT CASTING |
|
|
|
PROCESS
DEFINED
:
|
| Casting made by pouring metal into refractory or ceramic molds formed around wax patterns.
patterns are removed by melting in the
process of firing of the refractory. |
|
MATERIALS
: |
| iron, zinc, magnesium, copper alloys &
especially high alloy steels. |
|
RATE
OF PRODUCTION
: |
| usually
lowest of all process |
|
SIZE
& WEIGHT OF PARTS
: |
| small parts only. max weight of part about 10LB r
up to 20LB special techniques. section size
usually limited to 7in. or less. |
|
STRENGTH
OF PARTS
: |
| equal
to or better than permanent mold castings. |
|
WALL
THICKNESS
: |
| 0.040in.
min. 1/16in. prescribed min. tolerance on
walls no less than 0.005in. min. |
|
COMPLEX
ITY
: |
| intricate
shapes not readily made by machining forging or sand casting can be produced. |
|
OTHER
CHARACTERISTICS
: |
| min. thickness f trailing edge equal t 0.015in.
min & preferably 0.025in. inserts not
practical. |
|
|
