Casting Process & Alloy Comparisons

Process Comparison Process Precision Sand Castings Rubber Plaster Molding Investment (Lost Wax) Castings Permanent Mold "Graphite" Permanent Mold Die Casting V-Process Castings Typical Size Range oz. - 100 lbs. oz. - 30 lbs. oz. - 20 lbs. oz. - 100 lbs. oz. - 10 lbs. oz. - 30 lbs. Up to 150 lbs. Tolerances ±.020" to 10", then add ±.001"/", thereafter. Add minimum of .010 " across the parting line and for cored features. ±.010" to 8", then add ±.001"/", thereafter. Add minimum of .005" across the parting line and for cored features. ±.003" to 1/4" ±.004" to 1/2" ±.005" to 3", then add ±.003"/". ±.015"/" to 1", then add ±.002"/". Add ±.010" to .030" across the parting line. ±.005" Add ±.002" across the parting line. ±.002"/" Add ±.015" across the parting line. ±.02" to 6", then add ±.002"/" Add ±.02" across the parting line. Flatness Within .015" (geometry dependent) Within .010" (geometry dependent) Within .015" (geometry dependent)         Surface Finish 120-175 RMS, except on cored areas. 63-125 RMS 63-125 RMS 150-300 RMS 25 RMS or better 32-63 RMS 125-150 RMS Minimum Draft Required 1/2° to 3° 1/2° to 2° None 2° to 4° 1° to 2° 1° to 3° None Minimum Wall Section Typical: .140"-.187" Minimum: .080" (geometry dependent) Typical: .100" -.187" Minimum: .040" (geometry dependent) .060" .187" .100" .030" to .060" .125" Typical Quantities All <2,000 <1,000 >500 500-1500 >2,500 All Typical Tooling Price (N.R.E.) $800 - 4K $3K - 15K $3K - 10K $5K - 15K $1.5K - 5.5K $5K - 250K $3K - 6K Nominal Lead Times Samples: 1 - 4 wks. Production: 1 - 5 wks. after approval. Samples: 2 - 4 wks. Production: 1 - 5 wks. after approval. Samples: 2 - 4 wks. Production: 5 - 12 wks. after approval. Samples: 8 - 20 wks. Production: 10 - 12 wks. after approval. Samples: 3 - 6 wks. Production: 2 - 4 wks. after approval. Lifetime use. Samples: 12 - 26 wks. Production: 8 - 14 wks. after approval. Samples: 2 - 6 wks. Production: 2 - 6 wks. after approval.

The following table illustrates properties of cast and wrought alloys.

Alloy Comparison Alloy Heat Treatment* Tensile Strength (ksi) Ultimate Tensile Strength (ksi)Yield Elongation in 2 inches (%) Typical Brinell Hardness (500 kgf load, (10-mm ball)) A356.2 F 19 - 3.0 40-70 A356.2 T51 23 16 - 45-75 A356.2 T6 30 20 3.0 55-90 A356.2 T7 31 29 3.0 60-90 A319 T6 31 20 1.5 65-95 535 (Almag) F 35 18 8.0 60-90 Zinc-ZA8 F 38 28 1.5 85-90 Zinc-ZA12 F 42 30 2 105-125 6061 (Wrought) T6 45 40 12.0 95 A380 (Die Cast) F 47 23 3.5 80

*Heat Treatment of Aluminum Castings F As Cast - Castings are cooled naturally from the mold in room temperature air with no further heat-treatment. T-51 Aging Treatment - Castings that are artificially aged by heating metal to 400F for 7-9 hours. T-6 Solution Heat-treated and Artificially Aged - Castings are Solution Heat-treated by heating metal to 1000F for 4-12 hours and quenched in water at 150-212F. T-7 Solution Heat-treated and Stabilized - Castings are stabilized to carry them beyond the point of maximum hardness, providing control of growth or residual stress, or both.