Comparing Materials

How can I compare materials?

The cost of materials is another important design consideration. Accurate comparisons require looking beyond the cost per pound or cost per cubic inch to fully analyze the advantages and disadvantages of each competing process. For instance, the relatively greater strength of metals generally allows thinner walls and sections and consequently requires fewer cubic inches of material than plastics for a given application.

Effective Design Load example illustrations to help show how design and engineering can affect final production.

The following chart provides information on materials and their specific gravity and weight in pounds per cubic inch as an aid in material comparison.

Comparison of Metals

MATERIALS SPECIFIC GRAVITY LBS./CU. IN.
Metals
Magnesium AZ-91D-ingot 1.81 0.0653
Aluminum SAE-306

(380-1% Zinc)-ingot

2.77 0.100
Aluminum SAE-309 (360)-ingot 2.64 0.0953
Zinc SAE-903 (‘Zamak’ 3)-ingot 6.6 0.238
Brass-Yellow (#403)-ingot 8.5 0.307
Brass-85/5/5/5 (#115)-ingot 8.75 0.316
Steel-CR Alloy-strip 7.85 0.283
Steel-Dwg. Qual.-sheet 7.85 0.283
Steel-Stainless 304-bar 7.92 0.286
Iron-Pig, basic-pig 7.1 0.256
Plastics
Polyester (thermoplastic) 1.31 0.0473
Polystyrene–General Purpose 1.06 0.0383
Polypropylene Resin 0.905 0.0327
Polyvinyl Chloride (rigid) 1.20-1.37 0.0433-0.0494
Styrene Acrylonitrile (Copolymer) 1.07 0.0386
ABS Resins 1.04-1.06 0.0375-0.0383
Modified Acrylic Resin-Rubber 1.12-1.18 0.0404-0.0426
Cellulose Acetate Butyrate 1.19 0.0430
Modified Polyphenylene Oxide 1.06-1.10 0.0383-0.0397
Polycarbonate Resin 1.20 0.0433
Polysulfane 1.24 0.0448

Comparison of Materials

MATERIALS SPECIFIC GRAVITY LBS./CU. IN.
Polystyrene
20% Reinforced 1.20 0.0432
30% Reinforced 1.28 0.0462
Polypropylene
20% 1.04 0.0375
30% 1.13 0.0407
Styrene Acrylonitrile
20% 1.22 0.0440
30% 1.31 0.0472
ABS
20% 1.21-1.23 0.0439
30% 1.28 0.0462
Polyester (thermoplastic)
30% 1.52 0.0549
Polyphenylene Oxide (modified)
20% 1.21
30% 1.27 0.0458
Polycarbonate
20% 1.34 0.0484
30% 1.43 0.0516
Polysulfane
20% 1.38 0.0498
30% 1.45 0.0523