Inventables Community Forum

Carvey X Axis mechanical problems

Hi all,

Happy new year :slight_smile: I love my Carvey, but I’m experiencing a new problem with it… I’ve already contacted support, but figured I’d post here as well to see if anyone else has experienced similar issues.

In the past few days I noticed what seemed like a bit of jittery movement in the X-axis, specifically while the gantry was moving left (-X). It wasn’t affecting my cuts at first, but it quickly got worse. Now when I try to run anything with X movement in it, the machine will sometimes get “stuck” for a moment, and make a shuddering/grinding noise before continuing. This results in the machine skipping and losing it’s X-position, messing up the cut. After it happens, the rest of the cut is off by a few millimeters in the X-axis. Initial observations:

  • The skipping/shuddering only seems to occur while the gantry is moving left (-X). Both +X and -X movements seem like they are not very smooth, -X is just much worse.
  • It can occur during any -X move, even when the machine is NOT under load ie. cutting something. It even happens when the machine is just returning to the Home/Park position.
  • I powered off the machine and unplugged it. Then I gently moved the gantry back and forth (-X/+X) by hand. It does not move very smoothly. I can push/pull it but it sometimes “catches” or binds up a bit while moving left & I have to push harder to move it. I’m assuming this is the same thing happening during the “skips”.
  • It makes a bit of a vague grinding/metal-on-metal noise while I move it from left to right - I wonder if one of the linear bearings that slide along the X rails might be damaged/broken?

At this point I decided to take off the back control box panel to check on the X motor/belt/pulley system. Observations:

  • I did not see any obvious debris or damage to the X belt, pulley wheel, or gear on the stepper motor that might cause issues.
  • The belt seems to be under good tension, I plucked the bottom belt and it vibrated like a guitar string
  • The belt teeth maybe look a little worn, but not badly enough to cause issues
  • I was able to manually spin the pulley wheel to move the gantry - again, it didn’t feel smooth, but the belt didn’t seem to be the culprit.
  • I ran the machine with the back panel off and observed the problem again. I couldn’t tell if the belt teeth slipped or not, but if so, it seems like a symptom (of sticking in the rest of the gantry), not the cause.

That’s all I’ve done so far. I am thinking about taking the spindle and shroud off to see if it reveals anything else. I currently have two theories, do either of these sound likely?

  1. One of the linear bearings could be broken, so the gantry doesn’t slide smoothly (leading theory).
  2. It’s possible the gears inside the stepper motor are broken/grinding? I would have to remove the X belt to know whether the sticking is coming from the motor or the gantry itself.

I’m not sure how to test or remove the linear bearings to see if they’re the problem… Has anyone else had issues with them? Thanks in advance for any help!

-Dan

Does it slide smoothly by hand, powered off?

If so, it sounds like you may have a bad connection on the X-axis stepper. Check the wiring and connectors.

No - I can move it by hand, but it does not slide smoothly, it sticks/binds a bit and produces a bit of metal-on-metal sound. Seems like a mechanical issue :-/

That does sound mechanical.
The Carvey was not designed to be easily disassembled. I had the XZ carriage completely disassembled about a year ago and I don’t want to do it again.
If you end up disassembling or support sends you any information, please share updates for those of us that might have to go down that road.
Good luck!

Hey Dan did you ever get this issue resolved by any chance? jus asking because my carvey is having the exact same issue, I replaced the stepper motor, but it didn’t seem to help either. any help or updates would be much appreciated.

Hi Alen - not yet, though I’m working on troubleshooting it with the support team. If you haven’t contacted them yet, drop them an email, they’ve been helpful. But I’ll keep posting updates here too as I have them.

Unfortunately, while trying to remove the spindle to access the linear bearings, I snapped off the tip of my hex key in the top bolt of the spindle mount! The hex wrench I was using had a bit of a ball end which probably made it more susceptible to breaking. And apparently my torquing it caused the bolt head or the key to deform a bit because it’s stuck in there. I tried using a magnet, and also tried a using a dab of hot glue & toothpick to pull it out, but no luck yet… So now I’m troubleshooting two problems… I’m hoping I can just remove the spindle/mount together & not have to deal with that problem right now.

I am still leaning towards a linear bearing being the primary cause of my issue - I’ve been trying to listen carefully as I move the carriage, and it seems like the top left bearing makes a slight grinding/ticking/gritty sound not present in the others. Do you hear anything like that on yours?

I have another theory which could be a contributing factor: while moving the carriage, there seems to be more force required/friction present as it gets closer to the left side, and I hear a bit of a creaking/squeaking plastic sound that seems to be coming from the black plastic drag chain holding the X-axis cables in the back. It’s possible that excessive friction in the drag chain could be contributing to my issues. The left side/worst friction does seem to coincide with the time when the drag chain is under the most compressive force/has the most opportunity to bind.

Will post again if I make any more progress… Interested to hear if either of those symptoms line up with your experience too @AlenWStubbs

I am going to say something that will make you say: “does he think I’m stupid?”.
Make sure the two x-rails are lubricated. I can say this because I am stupid. I was experiencing terrible x axis problems. worried about all sorts of solutions, including taking off the back cover and rooting around there. Finally felt the rails and realized they were as dry as a bone. a little gun oil and all was well in the kingdom.