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SAND CASTING |
PERMANENT MOLD CASTING |
DIE CASTING |
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Description
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Tempered sand is packed onto wood or metal
pattern halves, removed from pattern,
assembled with or without cores, and metal is
poured into resultant cavities. Various core
materials can be used. Molds broken to remove
castings. Specialized Binders now in use can
improve tolerances and surface finish.
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Molten metal is gravity poured into cast iron
molds, coated with ceramic mold wash. Cores
can be metal, sand, sand shell or other.
Molds open and castings ejected. New L.P.P.M.
method pressure-pours with up to 15 psi.
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Molten metal is injected, under pressure, into
hardened steel dies, often water cooled. Dies
open and castings ejected.
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Metals
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Most all castable metals.
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Aluminum, Zinc, some Brass, Bronze, Lead, and
Gray Iron.
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Aluminum, Zinc, Magnesium and limited Brass.
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Size Range
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Limitation mainly foundry capabilities.
Ounces to many tons.
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Limitation mainly foundry capabilities.
Aluminum and copper base: ounces to 100 lbs.
Ferrous: 60 lbs. max.
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Not normally over 2 feet square. Some
foundries capable of larger sizes.
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Tolerances
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Non-Ferrous: +/- 1/32" to 6". Add +/- .003*
for each additional inch. Ferrous: +/- 1/32"
to 3" +/- 3/64" from 3" to 6". Across parting
line add +/- .020" to +/- .090" depending on
size (Assumes Metal Patterns).
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Aluminum: Basic +/- .015. Add +/- .002"/in.
If across parting line add +/- .010" to +/-
.030" depending on size. Copper Base: Similar
to investment. Iron +/- .03" Basic.
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Al
and Mg +/- .002"/in.
Zinc +/- .0015"/in.
Brass +/- .005"/in.
Add +/- .001" to +/- .015" across parting line
depending on size.
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+
Tooling Cost
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Wood: 5
Aluminum: 4
Iron: 2
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2
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1
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+
Part Price
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3-4 |
Non-Ferrous: 3-4
Ferrous: 4
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5
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+
Design Freedom
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2
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Non-Ferrous: 3
Ferrous: 5
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4
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Minimum Draft Requirements
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1°
to 5°
Cores: 1° to 1-1/2°
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Non-Ferrous:
Outside: 2°
Min. (3° desirable)
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Al
& Mg: 1° to 3°
Zinc: 1/2° to 2°
Brass: 2° to 5°
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++ Normal Minimum Section Thickness
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Non-ferrous: 1/8" to 1/4"
Ferrous: 1/4" to 3/8" |
Aluminum: .100" for small areas, up to 3/16"
or more for large areas.
Copper Base: .060"
Ferrous: 3/16" for small areas, 1/4" normal.
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Al: .03" small parts, .06" medium parts
Mg: .03 Small parts
Zinc: .025" Small parts
.040" medium parts
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Ordering Quantities
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All quantities |
Minimum One Day's run: (100-1000), depending
on size
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Usually 2,500 and up
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+++ Normal Lead Time
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Samples: 2-10 weeks
Production: 2-4 weeks A.S.A.
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Samples: 8-20 weeks
Production: 4-8 weeks A.S.A.
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Samples: 12-22 weeks
Production: 8-10 weeks A.S.A.
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+ 1 =
Most 5 = Least
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