checkered wrote:Wow, kurtiejjj
Carlos and SZ, thanks for your effort, really inspiring stuff. I hadn't even thought I could build my own private CNC lab!
lots of plan kits floating about on the web.
for a simple wood and foam router, david steele's plans are actually quite good and were a lot of inspiration for my own design (or you can build them as read). see
http://solsylva.com/cnc/cnchome.html. these are all three axis machines. plenty of kits for the motors and the drives (see the links enclosed) though i've seen it done really cheaply with stepper motors sourced off some really inane sources (dead photocopiers etc).
these plans certainly aren't the only ones out there. but they're quite well written, very well explained and quite straightforward to build (they also suited my needs very well).
a three axis machine with limited z travel may mean you'll be joining a few CNC'd bits together to make large scale parts, but foam is really, really cheap. so is glue. if you want rigidity to take a mold off, machine into fibreboard, or undercut the foam part 5-25mm, spray it with a filler, and then machine that. you'll be able to coat and take a fibreglass/PVC mold very easily (many a kit/supercar has it's composite panels built... in a process nearly exactly like this).
cost rises exponentially with the hardness of what you're cutting into and the speed at which you want to cut it. if you want to cut steel at an industrial rate with mega accuracy you'll need a super rigid machine and big, strong motors. big, big money. but if you're cutting foam at home and you're not concerned about whether a job takes 10 mins or 50 to cut...
with a little ingenuity you can also turn such machines into a digitizer (e.g. to scan an existing part). time consuming but very, very accurate.
five axis machines to cut foam made by DIY efforts are not unheard of - there's one in australia that can cut foam blocks large enough to mold complete car panel sections in made for about $US1500 - but it takes some serious programming skill to write your own g-code generator.
if you want to work metal at home for small model work you're far off buying a lathe or mill to suit your needs, you'll have all the rigidity, lubrication, chucking etc needs right there even if it's second hand (so long as it's been looked after). remember, you can always convert a metalworking machine to CNC the homebrew way - it's not particularly expensive and the resulting accuracy/repeatability/speed with which you can make interesting stuff is quite amazing.
i would seriously consider building a small three axis machine to cut foam and wooden models in... your skill in designing parts will develop very quickly once you have a means of inexpensively prototyping what you've worked on.
