Designed for Vertical X-axis competition.
PCB manufacture needs to be easier for reprap; countless numbers of printed parts can be made, but I see electronics as a real bottleneck. Just like 3D printing, the more accessible it is, the better the take up. To this end, I have started designing a milling carriage for the Vertical X-axis standard.
The idea is that the normal x-carriage can be unclipped from the x-axis, leaving LM8UU bearings on the linear rods, then this one can be clipped on to mill PCBs or other small parts.
Basic reprap PCB milling page here: http://reprap.org/wiki/PCB_Milling
Linear mounts are 70mm apart, as per the standard http://reprap.org/wiki/Vertical_X_Axis_Standard.
The LM8UU Linear bearing mounts were taken from Josef PrÅ¯Å¡a/Greg Frost's X-end holders, which I think have the best grip on the bearings: http://github.com/prusajr/PrusaMendel. I guess my idea is that it could be swapped, not that you'd be doing it every day. I have found Greg's other design http://www.thingiverse.com/thing:9871 doesn't have as strong a hold, and is more difficult to print reliably (lots of small towers).
Spindle layout is based on David Carr's Mantis 9 Low Cost Spindle v2.0 http://makeyourbot.org/low-cost-spindle-2-0.
The carriage will incorporate the belt doubling system from Madkite http://www.thingiverse.com/thing:8852 that Emmanuel is building into the Vertical X-axis he has designed http://reprap.org/wiki/X-carriage-struder and http://www.thingiverse.com/thing:10711
More details to follow on vitamins required, once I work them out!
It's not ready to be printed yet. STLs generated by the .scad file need fixing (I used Netfabb Basic edition). Spacing needs to be refined, but it's a start. There are no belt mounts at present.
I see the main problems using a reprap for milling as:
- Using belts to drive something that should really be driven by leadscrews - Madkite's belt doubling technique I hope will improve the belt situation
- Wobble in the drill - David Carr's spindle design should eliminate problems at the motor/spindle that others have seen using various Dremel-style drills
- Wobble in a X-axis - hopefully the change to a vertical X-axis should mean this is much more tightly constrained
- Wobble in the frame - The larger problem is the X-axis pushing left and right. I'm designing a simple cross-brace to triangulate this area with threaded rod. It's not ideal for 3D printing as it will interfere with the build area, but will not get in the way of milling, and will be easily removed to convert back to printing.
Any observations, comments and/or suggestions gratefully received!
- Don't print
- Don't fit motor and spindle
- Don't try and mill PCBs
- But if you do, tell me what you did!