So I’m suddenly having an issue with a stuttering yaxis that suddenly started while doing very gentle cuts… It is very obvious from the loud sound it makes (vibrating loudly). I’m guessing it became an issue over time and crossed some threshold. I’ve made sure the vwheels are all properly tightened, and it seems like an electrical/electronic issue (but is consistent no matter where it is on located on the axis). Sometimes it even jolts in the wrong direction(very briefly)
Any suggestions for how to fix this or if it may be a different issue than a potential continuity issue in the cable? My next step seems like fixing the cable, which I haven’t done, should I use a larger/specific gauge ?
Any input would be greatly appreciated, thanks ya’ll
18 or 20 gauge 4 conductor shielded security cable should work well — just buy a length sufficient that the connectors can be moved out of the drag chains.
Before you start yanking cables double check that your stepper motor set screws are on at least on flat. You can put a black mark across the stepper pulley and the shaft. Then jog back and forth to see if the wittiness mark stays in place. The SO3 seems to have solid wiring. So just double check the pulley and/or belt before starting on electrical.
Another check is to power off the Shapeoko and slowly move the gantry back and forth to see if you have any rough spots. Move slowly or the stepper motors make a field and will sound like a slipping belt.
Okay here are some updates. It seems to be an issue with the motor itself?
When I remove the motor to see how it behaves when I jog a single step (repeatedly in the same direction) it goes back and forth… this behavior is worse at smaller steps, going ‘fast’ in one direction mostly looks okay (except shuddering at the beginning). Here is some video of me jogging it in the SAME direction repeatedly
P.s. I can turn the pulley when it is on and the machine is engaged when it was attached still but the motor doesnt turn at all when I force it by hand (and there) https://youtube.com/shorts/W3itYTSlA4I?feature=shares
So now I’m not so sure it’s a wiring issue?? Although this is still plausible??!? Any insights would be really helpful.
This also seems to apply (I might call it a ‘sticky motor’ since it takes some work to turn when off)
Steppers are always a bit lumpy to turn, even when off, so that’s not necessarily an issue.
The behaviour looks like only one of the two sets of windings is active.
Since you already removed the motor, did you try plugging it into the connector for the other Y motor to see if it’s the motor or the wiring?
If you have a multimeter you could check to see that you have a low resistance across both pairs of the four wires that go into the motor. There should be two separate pairs feeding two sets of windings.
As @LiamN stated a stepper motor when rotated gets EMF. That can feel like resistance when turning. Always turn a stepper slowly to help you from getting EMF. The SO3 and SO4 are belt driven and if you move the gantry too fast it feels like a slipping belt. On the Ball driven machines it is very hard to manually turn them with enough speed to get the EMF. The reason is the two fields inside the stepper motor will generate an electrical field when rotated with the power off. The resistance is the two fields fighting with each other. A shuddering stepper is usually one of two things.
The set screws and/or couplers have a loose set screw. One of the set screws should always be on the flat of the stepper motor.
The second most common problem is loose connectors at the connectors. You can usually tell that by just feeling the connectors and if one of the terminals is hot that is caused by the loose connection causing high resistance and heat is generated.
Does seem to be the wiring and when I bypassed (by plugging the motor directly into the circuit board everything worked fine)
But NEW concern.
A. There is discoloration on the wiring on the ports of all axes… and probably due to heat because (especially the xaxis) is getting VERY HOT)
Is that normal? I never checked bc I never had an issue and I didn’t assemble this one
Any input or suggestions would be greatly appreciated I don’t want my board or wires to fry more!! It is working fine and communicating and jogging as normal once I bypassed those wires
No, heat and discoloration are not normal — they indicate the resistance of a poor/intermittent connection — let us know about this at support@carbide3d.com
18 gauge security cable is sold in bulk by the foot at most hardware stores (but is criticized as possibly not being flexible enough), e.g., Home Depot’s 18-4 CL3R Security Cbl Shld 1’ @ 0.63, Part number 0000-249-865 Ed0345.18.10 , listed by the foot on their site. Most larger hardware stores will have a carrel or rack near the electrical wiring area which has spools of wire which are sold by the foot.
