A tragic saga with a sweet and happy ending … OH, and a new vacuum mount

Let me tell you the story of a saga, two-months in the making. See, the CNC mill has not been working properly, at all! The z-axis was the main culprit. It would be engraving nicely, and suddenly, it would stall and lose 1/8 to 1/2 inches and completely destroy the piece I was working on. I’ve been trying to troubleshoot this from the computer to the machine! Why oh why was this happening to me? I used to have plenty of time to get presents done for the holidays!

Well, yesterday was the last straw for me. I was near ready to give up. Nothing was working with troubleshooting and I was out of time! So, what did I do? I started from the ground up, and learned a few things.

I stripped all of the wiring from the machine, since the last piece I hadn’t tested was in my wiring. When I started the build of the CNC, I thought it would be great to have a portable control box, in the event I built another machine. That way, I would only have one driver to worry about. So, I built the box and a six foot cable to hook up to the machine. Little did I know how much trouble this simple setup had caused me over the past few months.

I removed the driver from the box and affixed it to the back of the mill. I then rewired from the driver direct to the motors, using no coupling devices — just solder and heat shrink. Once this was done, I fired up the machine. DAMN, there was a short in the z-axis somewhere and smoke began to pour from the driver board. Lucky for me, I had a slew of spare-parts and rebuilt the board, fixed the wiring and turned it back on. NO SMOKE! This is certainly a good sign. But, I could not hear the motors. Was the driver dead?

Off went the mill. I decided to rebuild the control computer with XP in standard PC mode, as this is how it was recommended on the Mach3 website. Driver testing showed system as excellent, and there were very few spikes in the reading. WOW, the machine has never shown this before. Parallel ports plugged in; mill turned on; still, silence. Crap, what could possibly be wrong? The motors gave off a lot of hissing and humming noises before. Time to test a jog. IT MOVED! The machine was working great!

The z-axis was still losing steps in testing. This discouraged me, because 7 hours had been wasted. Previously I was running the zed at 1/8 steps. I had flipped it to no microstepping when things were getting at their worst. So, I decided to try it at 1/2 step mode. BAM! All problems solved. Now, I can create, instead of fix. What a happy ending, and I didn’t have to give the machine to my buddy Chugs.

So, what did I learn? Too much resistance and stepper motors, combined with a cheapo Chinese driver is a bad thing. There was simply too much resistance for the power being sent to the motors. This was causing noise, stuttering in the motors, and all manner of irritations. Lesson learned! And it was a good lesson, as all of my previous mistakes will be avoided in the X-CNC:Gen.2 build next year.

Ok, on to the new vacuum mount. I built a new mount that gave more room between the suck-redistributor and the piece that was being worked on. The first few pictures are from the first design. BAD DESIGN! There was not enough room in the suck zone. But, it was a good proof of concept, none-the-less. So, I redesigned, cutout, and rebuilt. New vac/IR mount is working great. Too bad I didn’t have enough time to put that new can of paint on it. Perhaps, that will come later.

New Z-Axis

Having been quite disappointed in the rigidity of my plunges, and with a lack of success on projects since the Acrylic Debacle of ’11, I got torqued-off yesterday and rebuilt my z-axis. Why you ask? For one, all hard plunges into soft wood would cause the entire z-axis section of the gantry to deflect outward, by as much as 1/32″. This is BAD. So, I decided to tear it apart and start over. My goal was to move the lead screw as close to the z-axis as possible. Before, it was several inches behind the main gantry. This lack of proximity, I gathered, was causing part of the problem, by applying too much torque to an otherwise less-than-rigid design.

I cut out new parts, moved the lead nut lower, and now the lead screw is MUCH closer to the z-axis. Plunges are now nice and straight down, without the prior deflection. This has made cutting much better, imho. The only problem now is, the lead nut is at the bottom of the y-gantry. AH OH, I can’t move the router as high as I used to. Oh well, I have enough cutting room for now, so I guess, I’ll make due, until X-CNC:Gen.2 is in the making.

Blue Lake

Blue Lake is a thermal lake located south of Wendover, Nevada on the Nevada-Utah border. The lake is around 75 degrees year round and is a popular spot for winter diving. Bring your bug spray during the summer months. There are a ton of bugs.
Fees: Free