Just came across some info on home/shop CNC routers and was wondering if anyone here has experience with this equipment. I'm spending a lot of time hand tooling and carving models for casting these days and saw a commercial about a home sized CNC routes for about $1800. Seems like that would save a lot of time! Did a few googles and found there are a few models in this price range to be had.
Questions for anyone with experience using these:
How fine of detail can a typical *home model* actually handle? For example could it handle a full relief sculpt, similar in size and detail to coinage?
I saw some ads claiming they can do metals like aluminum with no lube or coolant, do they actually work? Ideally one could use this tool for a master mold in metal, plastic or hardened wax.
There seems to be plans available to build one of these yourself. Anyone here done that and if so can you share your experience as far as costs and results using your machine vs an off-the-shelf model?
Seems like a pretty useful tool, any info appreciated.
I recently helped one of my vendors set up a 100" x 50" ShopSabre router. This wasn't a "home shop" version, costing roughly $40K, all-up (includes phase converter, special 80Krpm router head, BIG stand, 20HP vacuum system, etc).
I did all the initial g-code models for him. The CAD system he had wouldn't optimize the vectors very well, and he was wasting tons of time per sheet, waiting for no-cut slews to places the cut lines could've led to if the optimizer had worked well. His system also generated in-line code for multiple identical pieces, making the code large, hard to read, and nearly impossible to hand-edit for small changes. Hand coding was actually superior, although I've been assured that a well-written CAD and G-code converter package would have worked far better.
Look at the step distance. Even the 'baby' homebuilts are often good to less than 0.005". In "sculpting" mode, 5-thou wouldn't be a visible deviation from the intended lines. The ShopSabre, IIRC, micro-steps to point-two thou. Though, I doubt you'd ever see or need that on 'normal' work. This isn't a milling machine for making articulating mechanical parts -- it's a router.
'Pends on the feed rate, type of tool, depth of cut.... I dunno about routing Al without a lubricant... seems like you'd get chips and "false edges" stuck to the bits. Other folks are better equipped to evaluate that. The router head Tony got is speed-controlled by the G-code, so you can accurately control the SFPM.
3-D sculpting might require - in addition to X-Y-Z feeds, two more axes of tilt on the head in order to efficiently handle "side cuts". These might be done by bit changes, instead... never tried.
There are lots of plans for machines of differing capability, speed, and accuracy. After seeing the ShobSabre at work, I got a bad case of tool envy, and am planning a smaller machine for my shop.
It's revolutionized Tony's shop. The quality and consistency of the many duplicate parts he was making before by jig and have gone up to where the parts look almost "molded" from wood.
[The one you saw an ad for was probably the Carvewright machine that Sears sells as the "CompuCut". It's an interesting machine, but seems limited by its proprietary software which doesn't use the G-code that most machines run (and most CAM programs generate) so you either have to do a "heightfield" from a graphic file (dark pixels go low, light ones go high) or use their canned 3d "clip art". It does have an optional touch-probe scanner function, but I don't know how well that works. Most CNC routers are more expensive, but have a more open architecture, so they interface better with third-party software.]
[That would be better done on a milling machine than a router. For highly-detailed things like the lettering on coins, you need a high-speed spindle with low runout, capable of handling very small tooling, and more rigidity than you'd expect from a router.]
[You should use some lube when cutting aluminum, or it sticks to the cutter. Plastic or wax is a better choice of materials for a router than metal.]
[I'll have to get back to you on that when my home-built machine is done, but it's based on my own plans and some parts I scrounged up, so I'm not sure if it's applicable to machines built from the plan sets you're talking about.]
[It could be, if you can work within its limitations.]
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