[XYZ_dude]

Guys im not new to cnc but im not a pro,

i have been fiddling with my small 12x24 machine for the past year and i now need a larger machine but a decent quality one! someone told me to stay away from ball screw setups but i need some help to direct me to some good sellers, or machines. i want a solid machine and no real backlash problem that will give me headaches.

either complete turn key setups or i can use my current gecko drive to run one

i need at least 24x24 and have just a tad over $2k to spend,

any help appreciated! i have been on allot of pages and checking resources from the site and its just overwhelming what i find.

thanks guys!


what do you guys think of this setup?

http://www.cnczone.com/forums/produc...ter_frame.html


i will be milling wood and aluminum g10 and acrylic but nothing over 1" height, so all i need is 3"-4" z axis.

[awerby]

That machine you pointed to (I looked at the pictures on page one, but didn't read all 100+ pages of that thread) has unsupported round rails that will have a hard enough time making an accurate cut in wood - the cutting forces will cause it to bounce around a lot. I don't think it would do a very good job at milling aluminum. For that, even the best, most rigid wood routers have a difficult time holding tolerances; something like that kit really isn't designed for it.

Shop around and find some good square-section linear rails with ball-bearing trucks that you can screw down to something fairly massive and very flat. That will give you your best shot at the rigidity needed to handle aluminum. If you really can't tolerate backlash, screws are the way to go. You can get precision-ground or precision-rolled ballscrews that are pre-loaded to reduce backlash, or use acme screws with spring-loaded anti-backlash nuts. Rack and pinion systems generally need a certain amount of slop in them in order to work, although I've heard of some that have dual pinions that are spring-loaded against each other to eliminate backlash. As I recall, though, they were pretty expensive.

Andrew Werby
ComputerSculpture.com — Home Page for Discount Hardware & Software

[XYZ_dude]

That machine you pointed to (I looked at the pictures on page one, but didn't read all 100+ pages of that thread) has unsupported round rails that will have a hard enough time making an accurate cut in wood - the cutting forces will cause it to bounce around a lot. I don't think it would do a very good job at milling aluminum. For that, even the best, most rigid wood routers have a difficult time holding tolerances; something like that kit really isn't designed for it.

Shop around and find some good square-section linear rails with ball-bearing trucks that you can screw down to something fairly massive and very flat. That will give you your best shot at the rigidity needed to handle aluminum. If you really can't tolerate backlash, screws are the way to go. You can get precision-ground or precision-rolled ballscrews that are pre-loaded to reduce backlash, or use acme screws with spring-loaded anti-backlash nuts. Rack and pinion systems generally need a certain amount of slop in them in order to work, although I've heard of some that have dual pinions that are spring-loaded against each other to eliminate backlash. As I recall, though, they were pretty expensive.

Andrew Werby
ComputerSculpture.com — Home Page for Discount Hardware & Software

i appreciate your response, i guess what im looking for then is someone to recommend a good machine within my budget and needs etc..

[DCobler]

I'm kind of in the same boat. I was looking at Vertical CNC Mills for my company, with a cutting area similar to yours. Unfortunately the simplest of CNC machines go for 7,500-12,500, and at this price you're usually missing out on big features, accuracy, and productivity. With your price range I feel your only chance may be to find a do-it-yourself kit or guide, or perhaps you can get lucky and find a used machine close to your location.