Z-Axis Motor "Failure"?

CNC Machines Shapeoko
1

I did a little looking through the forum and didn’t find my exact issue, but hopefully somebody has some ideas here.

System setup (no goofy modes, all stock except for Suckit):

  • SO3 XXL
  • Makita
  • Carbide Motion 4.0.409
  • Running C3D latest version of GRBL
  • Windows 7
  • CAM from Fusion360
  • Stock wasteboard with additional full size, one-piece 3/4" MDF secured on top, machine leveled with threaded inserts

I’ve not used my machine much in the last couple of months (other projects going on), but cut a couple of molds for some carbon fiber foils that I designed out of Corian yesterday and today. I’ve gotten good results with similar jobs in the past, so I’ve proven that the machine can do what I’m asking of it. I’m not running crazy feeds/speed, so I don’t think I’m working it hard, but I am using very very small step overs to get as good of a surface finish as possible (0.15 mm).

On initial setup, everything seemed fine, the Corian cut great, but suddenly near the end, the machine cut a deep groove along the x-axis. After one pass, it went back to normal. Didn’t understand what happened, so I went back to Fusion, checked the CAM (didn’t see the deep groove) and re-exported the gcode to make sure that it wasn’t the file.

When I setup to reaccomplish the job, I noticed that the Z-axis stepper sounded… “different” than normal. My X and Y sounded the same, but the Z was different and sort of “jittery”. It seemed to perform ok when I did a quick travel calibration check with calipers, so I just went with it. The second job came out great (see picture), so I figured the gcode was fine.

Since I was working with a piece of stock big enough for multiple jobs, I simply moved my Y by 95 mm, checked Z and started the third job. Near the end of this one, a similar thing happened, but in a different spot; it looks like the Z went too far down and it ran one or two passes at that depth. Suddenly though, it went back to normal and finished the job. Problem is, I have a long deep groove in what should be a very smooth surface.

All of the screws, V-wheels, belts, pulleys, etc. have been checked, nothing is loose or missing. I manually analyzed the gcode files in Excel, both files have the exact same minimum Z coordinates in them, so the first run wasn’t a problem with the code.

Do these stepper motors have potentiometers in them? It’s almost like the motor doesn’t move the correct distance b/c a pot had failed.

Sorry, polished white Corean is hard to take pictures of, lol. The shiny one is the second run after wet sanding a polish, the one with the groove is the third run. The first run looks similar, but with a wider groove in a different location.

Thanks for the help!!

20170918_000333
20170918_000333.jpg4032×3024 2.51 MB
20170918_000316
20170918_000316.jpg4032×3024 2.67 MB
20170917_193602
20170917_193602.jpg2138×2851 1.62 MB

1 Like
2

More likely it’s the electronics which have failed:

  • check the wiring — if possible w/ a multimeter
  • test the stepper driver by powering down and swapping the X and Z axis connections and then jogging each.

could be that a wiring fault has blown the stepper driver, so you may need two replacement parts.

3

No comment on the failure just a question about the mold…DLG tail feathers?

Dan

4

Yup, think you’re right Will; I unplugged both the X and Z and the now louder Z whine was gone. Swapped the motors and the Z sounded fine and worked smoothly; the X was now noisy and less smooth.

I’m running the 2.4d board, who do I need to call?

Thanks for the help!!

5

Dan, I can see the resemblance to DLG wings, but not quite what these are for. Ever seen a foiling catamaran?

Fast forward to ~1:00 in the video below.

Where are you in TX? I’m in San Antonio.

1 Like
6

support@carbide3d.com will either set you up w/ a new board (if you’re in warranty) or send you a purchase link for a replacement — if you would prefer some other sort of controller the community has a list of options here:

https://www.shapeoko.com/wiki/index.php/Parts#Microcontroller

(note that some of these are only appropriate for an SO1/2 and NEMA17 motors)

7

Thanks, will drop an email now!!

8

Amazing!!!

I lived on a ship for a little over a year in the military, but really know zero about boats (I was an aircraft mechanic). Those molds really look exactly like the tail feathers on a couple of my DLG’s (thinking they both would have similar design characteristics, just move through a different media?).

I’m in Haslet, which is pretty much the far northwest end of Fort Worth, just shy of Denton County.

Dan

9

I learn so many wonderful things from googling your comments, thanks Dan looks like great fun with the grandson in a couple more years…would a small battery powered prop to extend the flight time be too heavy or just remove the magic of the flight? Jude

10

That would be an entirely different animal. There are several different disciplines in RC gliding including power gliders like you speak of, as well as slope, DLG, and thermal with use of a winch or hi-start, etc., etc… I’ve flown nearly all of the different styles, but for me being a purest the completely non-powered type are my favorite. I haven’t flown in a couple years due to a REALLY bad shoulder injury/surgery, but I still have a few DLGs awaiting the day when I can do my discus launch again (hard to side arm anything when your biceps is detached and you’ve torn your labrum and rotator cuff…eeek!).

Dan

1 Like