[Knas]

Hello, i'm looking to build or buy a CNC machine but i'm not sure what's out there so i'm looking for suggestions.

Basically i'm looking to cut paper, plexi glass & soft metals with precision down to 0.1mm, the workable area needs to be at least 24" x 12". This would be primarily for 2d parts but i would like to have the option of doing some smaller 3d parts too.

I'm technically inclined and have no problems putting together a kit, i do not however want to make the parts myself but would like to find a place where i can buy everything and simply put it together. My budget for this is about $1500, any suggestions much appreciated.

Thanks

Karl

[awerby]

Paper? I suppose you could fit your machine with a drag knife, but most people who want to cut paper (and thin acrylic) use laser cutters. But I don't know where you'd get one of those in kit form.

Cutting metals (even "soft" ones) is an entirely different problem. You need a lot more rigidity than for cutting plastic and wood. Most people who want to do that start with a manual mill and retro-fit it to CNC, rather than attempting to build one from scratch. Routers, which are used for wood and plastics, can be a lot lighter, and are commonly built from components or kits. Which of these things do you want to do most? I don't see you building a machine that will do it all for the amount of money you're willing to spend.

Andrew Werby
www.computersculpture.com

[Knas]

hmm.. i actually have a pretty OK drill press, maybe retrofitting that with a milling table & cnc conversion is a much better idea in that case? Although adding the Z-drive to my drill press seems like it could be a serious PITA, it also won't do variable speed (which i'm not sure is necessary but i assume it could be). I couldn't find a terrible lot of information about this, it also seems that maybe my size requirement of 24" x 12" is a problem.

In regards to that; if using a CNC with a smaller cutting area, is it feasible to just reclamp larger items in another position to be able to cut larger pieces?

If i'd have to go with something that could only cut plexi i guess that's okay, i could also go up in budget slightly. There seems to be a whole lot of options out there, but that kinda just makes it more confusing to me.

Karl

[embraced]

You do not want to use a drill press for a spindle. They are not designed for lateral forces, and subjecting it to them will result in either ruining the bearings, causing the morse taper to fall out, or ruining the whole machine.

[awerby]

Not to mention having the Jacobs chuck embed itself in your face.

Variable speed is convenient, but hardly necessary.

While it's possible to re-fixture a part and cut other areas of it, that should be a last resort, since it's difficult to maintain registration.

I'd say find a kit that appeals to you and build it; the size you're talking about shouldn't be a problem. But cutting acrylic with a router is a bit touchy; the stuff tends to melt onto the cutters and break them, and it stinks while you're cutting it. If you can afford to step up to polycarbonate, it works a lot better.

Andrew Werby
www.computersculpture.com

[Knas]

Hmm okay so if i was okay with going with lower speeds, i could potentially cut aluminum (like 1/8") - right? Right now i'm looking at then Zenbot 2424 and the Fireball X90. The X90 is a little too small for my needs but shouldn't i be able to reclamp the material in another position and sort of "start over"? I realize the precision will be dependent on my clamping skills, but i assume that with training it shouldn't be that hard, no? I was also looking at the Bluechick, but read that perhaps the construction of that one isn't really sturdy enough for what i want to do.. Any thoughts on this? I'm def. upping my budget to at least $2k

[awerby]

Hmm okay so if i was okay with going with lower speeds, i could potentially cut aluminum (like 1/8") - right?

[That really depends on the machine you get, but it's more about rigidity and runout than about speeds.]

Right now i'm looking at then Zenbot 2424 and the Fireball X90. The X90 is a little too small for my needs but shouldn't i be able to reclamp the material in another position and sort of "start over"?

[That's possible, I suppose, but it's not easy, especially if you want accurate results.]

I realize the precision will be dependent on my clamping skills, but i assume that with training it shouldn't be that hard, no?

[You not only have to have good "clamping skills", but you'd need to break up your CAM programs into multiple parts with multiple zero points, and somehow get one to take up where the other left off. Who's going to train you to do that?]

I was also looking at the Bluechick, but read that perhaps the construction of that one isn't really sturdy enough for what i want to do.. Any thoughts on this? I'm def. upping my budget to at least $2k

[That will get you closer. Most of these machines you're looking at can cut wood or plastics, but aluminum is iffy at best. Here's a recent thread from someone here who's trying to cut aluminum on a Zenbot: http://www.cnczone.com/forums/genera...1_my_life.html ]

Andrew Werby
www.computersculpture.com

[Knas]

So.. are there any low-budget options out there that can do limited work in aluminum? I realize that i posted this in the "open source" forum, but really i don't care whether it's a kit or a ready unit, i just want to get started with something and don't want to sink a ton of money into something that's not going to fit my needs in the end. Perhaps there's something out there that one can upgrade after a while?

Also i was checking out zenbots website and they had a bunch of images of people doing cnc work in aluminum, granted that doesn't necessarily mean anything...