[Iain_M]

I spent days browsing through this forum looking at pictures of other people's builds, and reading up on what to do and not to do. Since my machine has been up and running reliably for a few months now figured it was time to put up some of my own pictures that may or may not be useful to other people.

General specs are ~96" of X travel, ~27" Y and 8" Z, less cutter length. X axis is belt driven, Y and Z are ballscrews. All three driven with 200W Yaskawa servos. Spindle is a 1.5kW watercooled ebay special. This was my first attempt at a project like this. Lots of help from this forum, and a friend who built a plasma table a few years ago.

Started with a frame to support the linear rails. 2 x 2 x .120 HSS legs and 3x2x.375 angle for the rails. Started drilling the first of many, many, many holes with my ancient little Craftsman drill press/makeshift 'mag' drill. Surprisingly the thing is still kicking, although the bearings sound just about shot.

[Iain_M]

Gantry is 4" aluminum channel capped with 1/2 aluminum plate. Uprights are 1/2" steel with motor tabs welded to the top. Thought the drill was going to die drilling those counterbores, but it survived. Finish at the bottom wasn't great on some of them, but who cares. Also mounted the rails for the y-axis. Drawings of them showed them pre-drilled for mounting, which wasn't the case, but only a minor issue. Same for the x and z rails.

[Iain_M]

Photos will start to get a bit out of order here, most of the steps for the z-axis. This is one area I want to redo completely. Too much slop in the bearings mounted the way they are with the amount of travel I have. Servo mount is now a piece of angle that is actually straight and aligned (after snapping the first coupler off the first time I tried to move it). At some point I'd like to upgrade the rails/bearings and mount them differently, but its working ok for now. Took about a billion pictures of the assembly steps to put the z-axis together, since it seemed like I was putting it together and taking it apart daily, and the order of operations was important. I did it wrong more than a few times only to realize it all had to come apart again to attach that one bit I forgot about.

[Iain_M]

Most of the y-axis and gantry setup

[Iain_M]

Belt drive, for the x-axis, cheesy belt holders and tensioner setup. Aside from some burning on a friend's plasma, and a bit of welding, this whole machine was made with hand tools, an undersized drill press and a cordless drill that packed it in right at the end after ~1000 drilled and tapped holes.

[Iain_M]

Most money I ever spent at once on Ebay, let alone on used stuff from the other side of the globe. All worked out flawlessly, and even though there was a fairly steep learning curve I'm glad I did servos over steppers. I'm using about 1/50th of the features these servo drives have, and these are fairly out of date by today's standards. Ultimately wasn't much more than a stepper based system would have been, and they have more jam than I'll ever use.

[Iain_M]

At this point most of the mechanical parts were done, and I started realizing how much I had underestimated the scope of the electrical details. I spent a long time planning out the mechanical bits, 3d models, proper drawings for most stuff, etc etc. Not so much for the wires. Once I got over the initial shock of 'I'm supposed to know what all this stuff connects to?!?' it actually wasn't too bad. Of the 30 or so wires on the servo drives, only about 10 are needed, and 4 of those are for encoders. One big order, and then a dozen or so small orders later I had most of what I needed in one place from Automation direct.

[Iain_M]

Closer it got to being 'done', the less interest I had in taking pictures of everything. For the most part it was finished here. I'll try to take some pictures this weekend of what it looks like now. If I can dig it out from under a pile of its own mess.

[Iain_M]

More or less what it looks like today. Still haven't gotten around to finishing the door for the panel. Started working on a vacuum table the other day. Sure nice to have someone else drilling holes for a change.

[wizard]

This is a nice build to say the least, kinda slipped past my notice. In fact I would have missed it but I've been so sick the last couple of days that cruising CNCZone is about the limits of my abilities right now. So what do you call this machine - the Jolly Green Giant? Nice colors by the way, it beats rust and black any day.

About this design the 96 x 27" travels seem a bit odd, do you have a specific use in mind to the long travel on X and the skinny Y?

[Iain_M]

Ha, I just call it the green machine. Wanted it to stand out immediately when the neighbors come over to complain about noise.

Mainly wanted to be able to handle full length sheet goods and didn't have room for a full 4x8. I'm making skis and boat parts mostly, so long skinny stuff. Wanted 24" of y travel but sized things up for the space I had available and it ended up at about 27" of travel. Could get a bit more out of it if I tried, but half a sheet is good enough for what I'm doing now.

Pic attached from last night. Finally plumbed the dust collection so that it works all the way to both ends of the x-axis travel. Filled three 5gal pails in about 45 minutes milling this mold down to size. Still have to take some pictures of the planetary gearbox on the x-axis. Resolution was a little coarse with just the belt drive. It worked before, but the servos didn't have enough torque for precision movements. Reduced the drive 5:1 and now it has all kinds of power and still rapids at 1200ipm, limited by the clock speed. Could adjust it up but don't see a reason to bother. The whole machine will skate around the room as it is, and I think the servos are only running at about half max speed.

[kevin swan]

Iain Nice build. How do You like the belt drive.I love the paint job

[Iain_M]

Thanks man. I love the belt drive. Very easy to set up, and it runs quiet. All the perks of a rack and pinion without the tensioning/backlash issues. Plus it let me package the drive motors nice and tidy which was an issue since I have a tiny garage and the footprint was important. The ballscrews are nice on the shorter runs, but an 8' long ballscrew was out of my budget. I see about .001-.002" backlash approaching a position from opposite sides, but the belts aren't as tight as they could be, and I've done pretty much nothing to try to dial that out. Just like a rack and pinion the inertia of the gantry will feed right back to the motors so you either need some beefy drives that can handle that, limit the speed/accel, or decouple it a bit which is a lot of what the planetary gearbox I added does. Don't recall the exact #s but I think its around 15:1 reduction between the motor and gantry now. Can still push the gantry out of the way with the power off which is handy, but it stops on a dime when needed.