Permanent Mold Castings
Molten metal is gravity poured into cast iron molds, or graphite molds coated with a ceramic mold wash. Cores can be metal, sand, sand shell, or other. Molds open and castings are ejected. The Low Pressure Permanent Mold method pressure-pours up to 15 p.s.i.
Aluminum, Zinc, some Brass, Bronze, H.C. Copper, Lead and Gray Iron.
Limitation mainly foundry capabilities. Aluminum and Copper base: ounces to 100 lbs. Ferrous: 60 lbs. max.
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.
Copper Base: 125-200RMS
Minimum Draft Requirements:
Outside: 2° Min (3° desirable)
Inside: 2° Min (4° desirable)
Ferrous: Outside: 1° Inside: 5°
Normal Minimum Section Thickness:
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.
Minimum one day's run: (100-1,000 depending on size).
Normal Lead Time:
Samples: 8-20 weeks.
4-8 weeks A.S.A.