Hi all,
I've been toying with the idea of building a CNC Mill. And with that, I must start with design! I've been lurking around the net on CNC Hobby projects and forums. Before I can model my design, I have some general questions about equipment that i think if answered would save me a lot of hassle and time.. perhaps even money.
Some basic info of what I am envisioning
Goal: 3 axis Steel and Aluminum milling machine. Repeatability the best I can get. Would be very happy with +/- .0012"
Budget: Undecided entirely. If I can reach good repeatability and power, a few thousand USD.
Work Envelope: 20" x 12" x 8" (X,Y,Z)
Motors: NEMA 34
MOTION CONTROL: Ebay ball screws, ebay HSR Linear Rails, 2 per axis, Z-Axis considering going with rod style ways to save money.
Spindle: Was looking at ebay spindles for a few hundred.
[B]Frame:/B] Custom machined steel frame design (bolt and assemble type design)
Table / Mounts: I may go with Aluminum for the table as a substrate and bolt a thinner (5/16") steel top to it for lessesning load on the X and Y axis motors. Aluminum mounts for different pieces where acceptable.
Control Gecko drive, not worried about electronics at the current time
With that said, here are my questions for the experts:
1.) With the HSR linear rails, I found that pricing for larger HSR rails gets pretty steep the wider you go. HSR25 has a major rail width of 23mm. Do you believe this is rigid enough (2), or would stepping up to a HSR 30/35 be worth the 50-100% increase in price?
2.) Assuming ebay parts and the best rigid design possible with this hardware, do you believe my repeatability is realistic with amazon/ebay ballscrews?
3.) What is the proper term for finding "accordion" chip guarding. I don't know how to word that. I am referring to the chip covers that stretch and contract with the table to cover the ways and screws.
Any other comments/tips on my design are welcomed. Thanks for reading.
Regards