Process Comparasion Chart

Process Description Metals Size Range Tolerances Tooling Costs  (1 Most-5 Least) Part price (1 Most-5 Least) Design Freedom (1-5) Surface Finish Draft Requirments Normal Minimum Section Thickness Ordering Quantities
Die Casting Molten metal is injected, under high pressure, into hardened steel dies which are often water or oil cooled. Dies are opened and castings are ejected. Aluminum, Zinc, Magnesium, Lead and limited Brass Usually under 2 feet square. Some foundries capable of larger sizes. Al and Mg ± .002”/in. Zinc ± .0015”/in. Brass ± .007”/in. Add ± .001” to ± .016” across parting line 1 5 4 32-63 RMS Al & Mg: 1° to 3° Zinc: ½° to 2° Brass: 2° to 5° Al: .03” Small parts .06” Medium parts Mg:  .03” Small parts .045” Medium parts Zinc: .025” Small parts .040” Medium parts Usually 2,500 and up.
Sand Casting Tempered sand is compacked onto wood or metal pattern halves, removed from pattern, assembled with or without cores to form a sand mold. Metal is poured into resultant cavities in the sand mold. Various core materials can be used. Molds are then broken apart to remove castings. Use of specialized binders and coatings in the sand mold can improve tolerances and surface finish. Most castable materials Limitation mainly foundry capabilities. From ounces to many tons Non-Ferrous: ± 1/32” to 6” Add ± .003” for each aditional inch. Ferrous : ± 1/32” to 3”, ± 3/64” from 3” to 6”. Aluminum: 4 Iron: 2 Wood: 5 3-4 2 Non-ferrous: 150-350 RMS Ferrous: 300-700 RMS 1° to 5° Cores: 1° to 1 1/2° Non-ferrous: 1/8” to ¼” Gray Iron: 1/8” D.I. & Steel: 3/16” All quantities
Investment Casting Wax is injected into aluminum dies to create wax replicas. Multiple "waxes" are then sprued to a runner system, dipped in layers of slurry which dries into a shell. The wax is then baked out, and metal poured in resultant cavity. Molds broken to remove castings. Most castable materials Fraction of an ounce to 150 lbs. ± .003” to ¼” ± .004” to ½” ± .005” per in. to 3” ± .003” for each additional inch. 3 1 1 63-125 RMS None .030” Small Areas .060” Larger Areas 100 and up
Permanent Mold Molten metal is gravity poured into steel or cast iron molds that have been coated with ceramic mold wash. Cores can be metal, sand, or shell. Molds open and castings ejected. Low Pressure Permanent Mold injects aluminum using up to 15 p.s.i. instead of gravity. Aluminum, Magnesium, Zinc, some Brass, Bronze, H.C. Copper, Lead, and Gray Iron. Limitation mainly foundry capabilities. Aluminum up to 400 lbs. Copper base alloys up to 100 lbs                    Ferrous: 60 lbs. 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. 2 Non-Ferrous 3-4 Ferrous 4 Non-Ferrous 3 Ferrous 5 Aluminum: 150-250 RMS Copper Base: 125-200 RMS Ferrous: 200-350 RMS Non-Ferrous: Outside: 2° Min. (3° desirable) Inside: 2° Min. (4° desirable) Ferrous: Outide: 1°, Inside: 5° Non-Ferrous: .100″ for small areas, up to 3/16″ or more for large areas. Ferrous:  3/16” Small Areas, ¼” Normal Copper Base: .060" Minimum One Day’s Run: (100-1,000, depending on size).
Plaster Mold A plaster slurry is poured onto pattern halves and allowed to set. Then the mold is removed from the pattern, baked, assembled, and metal is poured into resultant cavity. Molds are broken to remove castings Aluminum, Magnesium, Zinc, Limited Copper Base. Up to 500 square inch area. Copper Base much smaller. One side of parting line ± .005” up to 2”. Over 2” add ± .002”/in. Across parting line add ± .010”. 4 1 2 63-125 RMS External: 0° to ½ ° Internal: ½° to 2° .070” Usually low. Often used to prototype for other casting processes. Average: 50-250 pieces.
Miniature Zinc Die Casting Molten zinc is injected under high pressure into specialized hardenned steel die cavities creating net shape, flash free parts. Zinc alloys #3, #5, #7, and ZA8 Minuscule to 4 x 4 x 1 in. (10.16 x 10.16 x 2.54 cm) Miniature die casting has virtually no lower size limits Weighing up to .75lbs ±.0015 in across linear dimensions. 3 5 3-4 32-63 RMS 0.5° .020" 50,000/year
Sintered Powdered Metal Powdered metal is blended with binders. It is compacted by a mechanical press in a die to create a net shape "green" part. The green part is sintered in a furnace, chemically bonding the powdered metal together. Most ferrous and non-ferrous alloys Determined by surace area perpendicular to press, press tonnage, and required density. See Tables on Powdered Metal Page 3 5 4 32.5-138 RMS 0.060" 1000s and Up
MIM - Metal Injection Molding Very fine metal powders are mixed with a binder and injected into molds to create a "green" part. The binder is dissolved through various processes, leaving a fraile and porous "brown" part. The brown parts are sintered in a furnace at a temperature close to the melting point of the metals, binding the remaining alloy particles into a near net shape, high density part. Primarily ferrous alloys, limited copper base.​ titanium .0005 lbs. to .22 lbs. ±3% ( .003″/in.) 3 3 2 45 RMS 1/4° .015″ (Small Areas) Usually 10,000 and up
Forgings Metal is heated to a temperature whereas it becomes malleable and facilitates deformation. The heated metal is subjected to compressive forces, causing it to deform and take the shape of the dies. This can involve hammering, pressing, or rolling, depending on the specific forging method. After the metal has been shaped, it is allowed to cool gradually, often in a controlled environment like a furnace. Aluminum, Steel, Stainless Steel, Brass, Copper, Magnesium from parts whose largest dimension is less than 1 inch, to parts weighing more than 450,000 lbs Conventional Forging: ±0.030in Precision Near Net Forging: ±.015in 4 2 4 64.3 - 1000 RMS  AL: 0° to 2° Copper Al (Brass): 0° to 3° Steel: 5° to 7° Stainless Steel: 5° to 8° 0.4" All quantities. Higher volumes for closed die forgings.