@@ -37,15 +37,29 @@ Make sure to change 'type' to .step, and check the 'save to my computer' box. No
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@@ -37,15 +37,29 @@ Make sure to change 'type' to .step, and check the 'save to my computer' box. No
# Material Choice
# Material Choice
- bring over notes on material choice
I've made a little table of different materials we can use. Typically, I stick with Aluminium (on a waterjet) or Acrylic (on a laser). Alternately, Delrin or HDPE can be machined, Delrin is medium-ok to lasercut, and I haven't tried (but am curious about) composites like FR4 and FR1. Probably more towards FR1: glass is a PITA to machine.
- acrylic, cool, but req' move to heat-set everwhere: cannot tap cannot heat-ineret (very well)
In the fullness of time, and with infinite fab, I figure gantry components (especially elements which see bearing contact) should be made from steels, water or laser-cut.
| Material | Young's Modulus (GPA) | Specific Young's | Cost for 6mm x 24x24" | Machinability |
| --- | ---: | ---: | --- |
| ABS | 2 | ? | 52 | Not Dimensionally Stable, but OK to Machine |
| Nylon 6 | 3 | 2.5 | 130 | Painful |
| HDPE | 1 | ? | 23 | Easy |
| Acetal (Delrin) | 2.8 | ? | 89 | Breezy, also lasers, and non-cracking |
Torsion ain't easy, as they say. In a break from a bonafide software extravaganza, I've been walking through this design for a decent beam from flat stock, to back on RCT Gantry types.
Torsion ain't easy, as they say. In a break from a bonafide software extravaganza, I've been walking through this design for a decent beam from flat stock, to back on RCT Gantry types.
The beam design is straightforward, but I've also been occupied with joinery. A big driver here is the desire to make machines with laser cutters and acrylic, to really lower the threshold for fab-your-own-machine-ing. To that end, joints in acrylic that don't cause cracking has been the order.
The beam design is straightforward, but I've also been occupied with joinery. A big driver here is the desire to make machines with laser cutters and acrylic, to really lower the threshold for fab-your-own-machine-ing. To that end, joints in acrylic that don't cause cracking has been the order.
Typically, laser cut acrylic members are joined a-la this classic machinescrew-and-captured-nut joint:
Typically, laser cut acrylic members are joined a-la this classic machinescrew-and-captured-nut joint:
