Spindle Disaster - Crisis Averted

Hello all,

I was about to start my most ambitious project yet when I experienced a failure while doing some prep work. My wasteboard was rather nasty so I put in my trusty surfacing bit to clean it up a bit. It made it about 80% through the job when the spindle simply stopped. I stopped the job immediately, went to jog mode, and tried manually turning the spindle on/off. Unfortunately, I cannot get the spindle motor to turn on anymore. Carbide motion does not indicate an error, and all axis work as expected. Any ideas?

Thank you in advance for your assistance.
Dalton

Two: Bad board (driver) 75% sure this is the error, Bad motor (25%).

Contact Carbide3d Support.

First, I suggest you contact support, Jorge will sort you out in no time.

In the meantime, check to see if the wires going to your spindle motor are good. I have recently had several of mine fail.

In a separate note, what surfacing bit are you using?

Just sent the note off to support. The electrical connections are all in check, I am assuming Richard is correct in saying the driver has gone out. I have a few laying around in my workshop, but unfortunately lent my hex keys out to a friend so getting into the electronics is a no go for now.

I have been using a simple mortising bit from Amana tool.

https://www.amazon.com/Amana-Tool-45560-Mortising-Cleaning/dp/B000P4O9CG/ref=sr_1_8?ie=UTF8&qid=1479664698&sr=8-8&keywords=surfacing+bit

That’s awesome, I hadn’t realized the nomad could power one of those. What settings do you use for it? How long does it take to surface the bed?

Ummm, maybe it doesn’t

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@dmckee55
Your board is bad.

Don’t use that bit.

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@ApolloCrowe

Why not use this bit? The feed/speed used does not bog the spindle or axis motors.

It’s never been recommended to use a 3/4" bit in the Nomad. The board failed due to the bit you used.

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Well fun. Is there a list of recommended bits that I should point my attention to, or is the machine limited to using only bits supplied by Carbide 3D?

I have used 1/8" bits from multiple manufacturers without any issues on my Nomad classic. 1/4" bits work, but only on softer materials. I think anything larger will potentially cause problems. I recall someone using a fly cutter from micromark, but only on wax and plastic, I think. There have been threads about people upgrading to more powerful spindles, not sure if that would help, though.

I guess I overestimated the strength of the machine. I knew the larger bit would be harder to use but thought a machine that could cut 6061 could remove .005" of MDF with a big bit. Guess I will just have to wait to get a replacement board and look into upgrading at least the driver boards if not just all of the electronics.

I’ve been looking into the same thing. I know other GRBL based machines run .8KW VFD spindles. Is there something unique about the Nomad electronics that would prevent interfacing a different driver? I know physically it wouldn’t fit, but is this possible to have Nomad software and hardware control it?

It does not appear so. I will know more soon but the control board (probably an atMega328 board similar to an UNO) likely just sends the driver a pwm signal. Good news is that most motor drivers will be compatible with this.

I initially bought the Nomad, over the competition, based on the idea of not tinkering with it. That being said I think I have reached the point where my ECET degree has talked me into up scaling all of the electronics. The hardest part being the lack of room for the 800w spindle I would like to have.

In theory, yes, you could replace the spindle driver board with something else. Then you need to change out the spindle drive motor too. There’s a PWM output that goes to the spindle board to set speed (GRBL outputs a PWM signal to control speed - superpid can work using that pwm output from the main board, for example, and that’s how you would do it on a shapeoko). That said…not much you can actually mount on the nomad z-axis. There is a slightly more powerful motor (+20W) available that you can refit in there without too much hassle…but it doesn’t really make anything better, I wouldn’t recommend the hassle. Done it, not that exciting. Nomad spindle motor....upgrade?
So, practically speaking, you’re kind of stuck unless you can find/build a motor/mount assembly.

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@mikep

I appreciated your article, good read. More power, of significant gain, would certainly be a task, but robustness of the drivers could likely be upgraded (PPTC’s, TVS diodes, fuses, over-temp shutoff, etc. ). Have you looked into this during your endeavors? Curious if anyone has tried any of these since I saw a couple posts discussing board failure.

For every board failure I’ve seen here on the forum, Carbide’s been on top of it with a replacement.

Did look a little at it but I know they’ve done a newer board since the v4.3 I have. I have heard that it has more IC’s on it, but I haven’t seen one myself. I’m guessing it has a separate driver per phase on the new one. I didn’t think it was worth messing with until I had a real problem. I’ve stalled the spindle a few times, which has put the driver into overload (I think…it’s either that or the phase detectors are out of whack with the software), but you can recover from it by removing all the power from the board and restarting things. When I looked at the spindle driver vs. the new motor, it’s well within spec. I would take a better part without much argument, but there isn’t anything pin compatible, so it would take building a new board…that I just really wasn’t up to doing.

Another one to look at is the lack of snubber diodes on the servo drivers. That one in particular I don’t quite understand, and sort of bothers me. In the demo board for that driver there are optional snubbers, but they aren’t in the reference schematic in the data sheet at all. In every one of the “open” boards with that chip I can find they don’t include the snubbers. For the 20 cents it would add to the board, would probably make it a lot more robust. I’ve asked around, and can’t seem to find a reasonable answer to why they aren’t there on any of the open boards (I’ve heard a few “because they aren’t on the schematic” answers, and a few “I don’t know, it seems to work fine without them”) The bigger the servo, the bigger problem it would be I think. I hardly do anything electromechanical for my day job, so I’m sure there are plenty of others out there with better area knowledge on this.

If you come up with something, would like to see how it goes.

@dmckee55 @mikep My original spindle was stalling, so I did that 78 watt upgrade. Later I found out about the driver board issues. They sent me a new board and a heavier brass pulley. It is a lot stronger than what I had, but it’s still limited. The company Wantai making those BLDC’s use the same driver for much stronger Nema 23 steppers. I would think that could work if one of appropriate rpm’s could be found and you were willing to redesign enclosure. Also, over on CNCzone people are using small RC airplane motors. They are claiming 1HP or more can be achieved. They’re not designed to run for very long though. 15 minutes or so. A guy at the hobby shop thinks it could work with proper cooling. Othermill and EVO One are using something like this. Othermill uses TinyG though which I think might be better control wise as it’s 4 axis. Another idea I had was mounting a VFD outside and using a flex shaft mounted to the stock pulley.

@Jerrylee @mikep @ApolloCrowe

Well I received the replacement control board today. Was very impressed with how quickly Carbide3D was able to take care of me. Took maybe 15 minutes to do the swap and I was up and going. Thank you gentlemen!

I had also been intrigued seeing the RC plane motors being used on other machines such as the othermill. The very high RPM range of these motors should be quite nice for PCB milling and engraving work, but as you mentioned they are not really designed for very long milling times. I plan to spend some time in the coming month or so developing a game plan, but I think I am going to try out a setup with TinyG2 running on a Arduino Due with some GeckoDrive stepper motor drivers and a much beefier brushless motor driver for giggles. I am more opt to play around with the firmware and software portions of the machine when I know everything that is in the black box. Sort of want to play around with probing routines to get a better zero on PCB blanks.

That being said I will be moving this conversation to a new, relevant, thread in the coming month or so. Thank you all again.

List of links on D.I.Y. spindles: http://www.shapeoko.com/wiki/index.php/Spindle_Options#D.I.Y.

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