- Thickness: Varies (Tested 1/8" - 3/4")
- Speed: 30-60ipm
- Bit: single or double flute 1/8" end mill (with center point for drilling!)
- Depth Pass: 1/16" @50-60ipm or 1/8" @30-40ipm
- Spindle Speed: generic dremel turned up to 11
- [Wikipedia Link]
Info: When milling UHMW you want "chips" to come off the bit. If you find that you are instead getting "threads" of material you need to either increase your speed or increase your depth (preferably not both). You will notice a difference depending on the direction your mill is going. If you get a lot of "chatter" (bit seems to hop) while milling uphill (where bit is turning into the material) you'll want to slow your job down slightly.
There is a heat issue with all plastics, the idea is to remove as much material in one rotation of the spindle as possible then move on. If you dwell in one place too long your bit will heat up and the material will heat up, leading to distortion, bad smells, and dull bits.
There's a really good page on spindles and milling here: http://www.cncathome.com/spindles.html
plastic that can easily be found in your local supermarket as a white cutting board but are also available in other color. Only limitation is they only come in about 1/4"(6mm) thickness. Thicker material is available online.
(I have in mind to make rubber stamps, e.g. for a mini production run of home-made Christmas cards...)
I cut this as a test first cut before moving onto heavier materials. I used a conical shape cutter that came with my rotary tool. It's coated with some sort of rough particles. The edges of the cuts are rather messy, which would be tricky to clean up (e.g. with sandpaper), especially in areas where little "islands" have been cut (inside the "a" and "e") as there's not much left below to hold them in place.