Well, I set out on a multi-hour adventure to try to tie up some loose ends and get the CNC in a state where I could start to cut some parts. What actually happened is a whole lot of nothing. I managed to take a picture of myself working on the machine:
A human sized rabbit or a very tiny hurdle.
Anyways, my first goal was to get AutoCAD and CamBam up and running on my laptop. AutoCAD took forever to download and even longer to install. Let it go for some hours while I did other things and still wasn’t finished. Ended up rebooting the computer (Yay, Windows!) and restarting the install. Success. Alright, now I have a software “toolchain” completed – AutoCAD to design, CamBam to convert CAD into GCode, Universal G-Code Sender to send the NC file to GRBL. Next up, I attempted to calibrate the machine.
In a previous post, I mentioned this calibration tutorial. It’s pretty good and describes what you need to do in an easy-to-understand way. I started with my “Y” axis. (ie: The longer one.) My problem, though, is how to make precise measurements across 700mm of travel! My plan? Drill holes every 140mm and put dowels in the holes. Then, take a digital caliper and add up the distances between dowels (don’t forget to include dowel diameter!). I got the idea from this blog post. I had a some problems with this method, though. First, I didn’t have any dowels that fit into the 1/4″ holes I drilled with the router bit. Me so genius. So I decided to use some 1/4″ bolts I had lying around. This is a pretty bad idea, because the threads of the bolts make it hard to measure accurately. On top of it, they didn’t even fit snugly into the hole, so they wobbled around. I decided to forge on and see what would come of it. I told the machine to go 700mm, and from my completely BS calculations, I determined it actually went 703.06mm. I recalculated my steps/mm number and put it into GRBL. Time to test!
I didn’t want to drill a bunch of holes and use the calipers again, and I shouldn’t have to really, if my calibration is correct. If told to go 700mm, this time the machine should go 700mm (instead of like 701.181 or something), which I can easily measure with a normal ruler/yardstick. Problem is, I didn’t have one of those either. More genius points awarded. I did find a “sewing tape measure” which did have a centimeter scale on it. I hacked up a pen and put it into the DW660, drew a line, moved the machine +700 in the Y-Axis and drew another line. Then I used the sewing tape to measure. Wow, completely off! Totally worse! Alright, forget this for now, it’s getting late. I reset the steps/mm to the theoretical value and tried to get CamBam to cut a part.
Earlier in the week I drew up some parts to hold limit switches. The part attaches to the motor mount plate and has an adjustable slide so you can change when the switch will hit something and trigger:
I think it looks like a duck, but I could also be a moron that doesn’t know what a duck looks like.
So I got this part into CamBam and then goofed with it for 20-30 minutes before I realized I had no clue what I was doing in CamBam and was entirely too tired to actually figure it out properly. At this point, it was about 1AM, so I threw my hands up in the air (appropriately, like I just didn’t care) and shut down CamBam. I ended up cutting some squares in 1/8″ thick acrylic with an 1/8″ end mill by manually jogging the machine around via Universal G-Code Sender. The cuts were OK – kinda rough edges, which probably means I did not use an appropriate feed rate!
Things accomplished: Z-Axis wired up and correct steps/mm setting calculated.
Things not accomplished: Everything else.
To do: Actually calibrate the machine. Get acquainted with CamBam. Research good cutting settings to use for acrylic. Figure out clamping mechanism. Wire up limit switches. Clean up all wiring. Whew.