Hi again everyone! I've been away for a while, but wanted to come back and start a thread to document my new DIY project and get some input from you folks who have already done this sort of thing. I'll outline the basics here, and then update as necessary. Here's the general idea of what I want to achieve:
Phase 1: design and build metal-frame gear or worm-driven unit for desktop CNC routing applications - metal-frame for durability and ability to be scaled up to larger frame(s), and non-belt drive for precision and longevity.
Moving-spindle system instead of moving-table.
Software is pretty much open, of course expense is an issue. I don't want to have to learn to write GCode line by line, but I don't need it to be able to compute laser-carving in a bazillion axes (axises?), either. If I can generate the file in Corel or Adobe, feed it to the program, and have it cut my material within reasonable tolerances (within 1/32" is pretty loose, considering, but it'd be a starting point).
I've already found a chip/dust-evacuation system that suits my needs, so that part is covered.
Some of the sticking points include vaccum hold-down for sheet material (a ROOTS blower/pump is freakin' spendy), an oil-misting system for cutting sheet metal (we had one on our Multicam and it was awesome) - I could pay some kid to follow the spindle around with a spray-bottle of vegetable oil, but I'd rather figure out an automated dispenser/sprayer, material depth/height gauging (again, the Multicam had a block unit you'd set on the table, let the tool in the spindle make contact with the block to close a circut and tell the computer where the tabletop was, then repeat the process with the material set on the table).
Since I have access to oodles of scrap plex/lexan, I'm considering building a double-enclosure for the finished unit. This way, I can not only keep my work area clean and somewhat less noisy, but perhaps even setup an air-flow system that will keep whatever chip/dust gets away from the head evacuator from getting into gear teeth or worm drives.
Phase 2: Apply finished, de-bugged design to larger-scale table(s). Basically, I want to learn everything I can on the desktop unit and work out all the kinks I can on a smaller (2x2-4) before stepping up to something like a 4x8 or 8x10 unit (all sizes here are actual cutting space). Also, as my budget becomes more flexible, larger tables make more sense.
The desktop will be for learning and play, but the larger tables will be expected to at least cut letter faces and backs out of acrylic and sheet metal for sign applications.
I'd focus on buying a professional unit, but it would defeat the purpose of me knowing every single little nitpicking thing I can about how it's built, how to maintain it, and what I can expect it to do (at least as far as the hardware goes. As far as software goes, I don't mind paying a little extra to have the computer do most of that work for me). Also, like I said before, with DIY, my budget will allow for a multi-phase project such as this.
So - if I didn't already lose you in the above ramble, basically I need input in these specific areas:
Frame/Gantry: Metal-frame as opposed to MDF/wood/etc. I have access to plenty of steel angle, but I don't mind the cost of aluminum frame. I have access to a journeyman welder (steel/aluminum), but don't mind working with a clamped/screwed table (temporary) for a while until I have it all worked out and finalized for welding (freakin' permanent). Footprint is negotiable within reason, assume a 20x40' shop space for the bigger tables, 10x10 for the desktop.
Spindle/Head: I don't mind using a Rotozip or Dremel for the desktop unit, but will require something more robust for the larger tables. A Colombo is prohibitively expensive, but as long as it will perform within reason for the cost and I don't have to replace the dang thing every month.
Motors/controller: I'd rather skip any belt-driven system and move directly to gears or worm, unless someone has input on how a belt-drive would be better for my application than the other options. I don't know yet the pricing here locally to have gears and toothed rails precision-machined, so this is also something I'd like input on. It'd be nice if I don't have to mod the control unit too heavily to work with whatever motors I decide on.
Material hold-down: I'm considering an electro-magnet hold-down for at least the thinner gauges of sheet, but for thicker materials I'm willing to consider most anything that's practical and time-effective. I'd go totally vaccum-hold, but sadly, I've never found such an animal as a cheap ROOTS blower/pump.
Oil mister/sprayer: I got spoiled with this option when we had the Multicam, and noticed that we went through bits faster and messed up more material when we didn't use it. The mess isn't a huge deal, since the table will be cleaned thoroughly every day.
Software: If I can run it with Linux or Windows 2000 or XP, if it will process Adobe or Corel files to scale, if it will cut 2D and supports multi-pass cuts for thicker material - and I don't have to learn Gcode to use it or rob a bank to afford it, then I'll consider it.
Misc: Speed within reason, I don't know what kind of IPM I'm shooting for yet, but I'd like to be able to throw a sheet of plex or .060 aluminum or a couple inches of sign-foam and have it cut some letters or shapes out at least faster than I could cut it myself with a jigsaw. I can always find something to fill the lag time, but I'd rather not have to find busywork since the larger tables will eventually be expected to make money.
I'd rather not have to install three-phase power until or unless I absolutely have to, but it's negotiable.
See anything I missed? More to come as things happen.