Materials
The “ashby chart” relates density and stiffness:
Ben of CBA shows how lattices and metamaterials can expand this space here and here
See also these Univ. of Cambridge list of charts.
I’ve put this table together for practical use:
| Material | Young’s Modulus (GPA) | Density (kg/m^3) | Cost for 6mm x 24x24” | Machinability |
|---|---|---|---|---|
| HDPE | 1 | 960 | 23 | Easy |
| PLA | 1.8 | 1240 | ($30 / kg) | 3DP |
| ABS | 2 | 1050 | 52 | Not Dimensionally Stable, but OK to Machine |
| Acetal (Delrin) | 2.8 | 1300 | 89 | Breezy, also lasers, and non-cracking |
| Nylon 6 | 3 | 1100 | 130 | Painful |
| Cast Acrylic | 3.3 | 1100 | 46 | Breezy, esp. w/ Lasers |
| FR1/CE (Canvas / Phenolic) | 6 | ~1850 | 81 | TBD, probably WJ Pain and Ease on SB |
| FR4/G10 (Fiberglass) | 22 | ~1850 | 98 | Painful on a WJ, Slightly Easier on a Shopbot |
| 6061 ALU | 69 | 2710 | 87 | Breezy with WJ, Painful on Shopbot |
| Steel | 200 | 7860 | ~ 200 | Yes |