Hi, all,
Well, after reading so many great build logs on this site, I thought I should probably start my own, in case I can spark some ideas in others. I came at the CNC build from a slightly different approach from most, I think - I'm a graphics programmer for video games, and lack many of the tools you might normally need for a project like this, so I mostly focused on writing my own software to control the machine and tried to find ready-made parts for as much of the build as I could.
I want to use my machine mostly for making costume props, so super-fine detail work wasn't as important to me as large sizes. Thus, my machine has a footprint of about 55" x 34" x 28", with a moving gantry to give me a cutting area of 45" x 28" x 12". I don't think I'd want to try it with a 12" bit, but even shorter bits will let me get deeper carvings because of the vertical travel.
To solve my lack of tools problem, I did a lot of shopping at
http://automation4less.com and
http://automation-overstock.com. It's hard to beat the 80/20 extrusion for ease of bolting together. I decided to go with the 15-lite series of extrusion, to try to keep the weight down a bit, and to match up with Ahren's
http://www.cncrouterparts.com parts - motor mounts and bearing blocks. I mated those with ACME screw connectors and anti-backlash leadnust from
http://dumpstercnc.com, 1/2" 10 turn screws from
http://www.mscdirect.com/, and bearings from
http://www.vxb.com/. To drive the whole thing, I went with a 3-axis 4030 425oz kit from
http://www.kelinginc.net/, which I added an additional motor and 4030 driver to so that I could have dual motors driving the gantry. All of this is riding on 30mm Hiwin rails from automation-overstock, which nicely can bolt through the top onto the 15 series aluminum. And they're thick enough that they will never move under the usage I envision for them. In fact, part of the reason I chose the sizes I did for my layout is because the numbers match up nicely between imperial and metric - 55" == 1397mm, for example.
After seeing some other posts on this forum, I set up the electronics in an old PC case, which seems to work out just fine, and looks better than a lot of other approaches I had access to.
The only really custom part I had to get made was a connector to get the leadnuts to attach to my 80/20. For this, I went down to a local shop called
http://www.tapplastics.com/, which does custom plastic cutting for a low fee. I was able to get all four of my nut/aluminum connectors made for $30 - for the vertical axis, I used 1" thick acrylic, and for the others I used 1/2".
At this point, my machine is mostly built - I need a better dremel mount (or I need to upgrade to a router, but that's a question for another day), and protection for my control wires. But it moves, even if it is a bit on the loud side to be using in an apartment. I've been hunting around for ideas on how to fix or at least hide the sound, and will probably be ordering some sound dampening foam in the next week or so.
This post is already getting on the long side, so I'll wrap it up with this - if someone like me, without access to a tool shop, or even much in the way of experience, can build a CNC machine, anyone can. I'll come back later to post pictures and details about the program I wrote to run the whole thing later, if people are interested.