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 |