Nomad Y axis too far back causes hang/halt. (cause found)

(Wing Wong) #1

So I’m finding that using a CNC machine is very much like using a 3D printer, in that there are just so many things that can come together to create minor issues. -_-;

Recently, I’ve been finding that when I back up my Y axis all the way towards the back, the Nomad 883 Pro would just hang. Like, hard hang, then the front power button just stays on, etc. Not a happy situation. Had to pull the plug to get the machine to stop. Afterwards, it seems like the front button just stays on and doesn’t respond to button presses anymore, though the board is accessible via USB and can be jog’d, homed, etc.

Something like this happened to me before with a printer, so flipping the Nomad over(no small feat…) I noticed that the VERY beefy Y axis carriage(Thank you Carbide3d! VERY IMPRESSIVE!) was designed to back up as far as it can and accommodate the NEMA17 stepper in the back. But either due to one thing or another, the stepper wire leads came out on the side, where the rather accurately milled edges of the platform would cut into the leads, causing a short. --;;; I’m guessing this is causing the error state. 2 of the leads have had the plastic ground off in this manner. The leads are pretty tight, no slack. Ideally, I’d route them along the ceiling of the underside of the machine since this would clear the carriage and other bits, or route it hanging, so that it will miss the carriage. But due to lack of slack, this means a small but real chance of getting caught on the carriage. Another possibility is to flip the motor backwards so that the leads are against the back wall(ideal) and out of the way of everything. But this means taking apart the stepper motor and I’m not sure I want to do that. --;;

I’m thinking I’ll extend the leads and use some stiff plastic to route them in a sane manner away from the Y-axis carriage. (Did I mention… DANG THAT IS A BEEFY CARRIAGE!? sorry, in the home 3d printing world, the goal is a lighter carriage, so seeing so much aluminum is awe inspiring to me. lol!)

Some pics of the motor under my Nomad 883 Pro:

Above: I’ve unbolted the NEMA17 from the frame and from the carriage to get a sense of how much wiggle room I have. As you can see, the blue and green leads’ insulation has failed due to physical contact with the y-axis carriage. If only the leads were on the back side against the frame…

Above: Here it is put back in position with the Y-axis carriage gently slid back to illustrate the failure condition. -_-; Ouch! Wouldn’t want my finger there.

Above: Just from a higher angle. Based on the rubbings, the red wire is the next one to bite the dust. -_-;

Mainly posting this here for helping other folks who are trying to diagnose why when their Y-axis carriage goes all the way to the back, everything locks up. A short for the Y-axis stepper motor is one possibility. Since the frame is wired to ground, a connection to any of the stepper lines would result in a short to ground. I’m assuming the stepper drivers on the control board detects this and raises an error condition.

Solutions I’m going to attempt:

  1. Recover the edges or just resolder new leads to the motor(involves taking the motor apart) and add a few inches to the total length of the leads.
  2. Most likely with the lead exit facing down with a plastic shim/guide to lead it to the back wall towards the cable tie down anchor.

Will update once I’ve made some progress.

(Wing Wong) #2

Btw, @Carbide3d, THANK YOU THANK YOU for the following design elements you put into the Y-axis carriage!

  • Milled circular well inset into the back frame. Makes re-aligning the stepper motor on re-installation painless.
  • Using a beefy hunk of aluminum for the carriage and doing the motor body sized well to allow for movement… avoids motor “hump” sticking out the back of unit.

So far, loving on the mill. As others have noted, there are things here and there that could use tweaks(better tolerance for voltage dips/spikes like when a shopvac turned on nearby), but so far, much of what I’m needing to tinker with are just things that come with old age for hardware. It’s so interesting to look at the millings caught here and there and see what previous owners of this mill have milled. :slight_smile:

(Wing Wong) #3

So update: i ended up rotating the motor so that the wiring is facing down/away from the machine. I used kapton tape to separate each i dividual wire from one another.

Test milled a part after flipping it back right side up and it is happy.

(Rob Grzesek) #4

Sorry for the trouble- that motor got installed with the wrong orientation. I’m glad you got it fixed but if you’d like us to send you a backup motor as a spare in case those wires ever break, just shoot us a support email with a link to this thread.

On a side note, I’m glad you like the carriage. On the first machine we made it a little lighter so that shipping could be affordable. Over time (and a lot of negotiating with UPS and Fedex) we realized that the shipping weight wasn’t a killer so we added a lot of metal to the Nomad Pro.

One final bit of carriage trivia- that Y axis is made on a Mori DMU-50 so that we get the best alignment possible -

(Wing Wong) #5

@robgrz thanks, and I’ll take you up on your offer and send support an email with a link here.

Awesome CNC milling for the carriage. :slight_smile: