I have an issue with my Shapeoko 2, please help me to debug it:

General CNC CNC Routers
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1

I have an issue with my Shapeoko 2, please help me to debug it: during my first real cut, it has jumped about 10mm on the X-axis. I’ve also recorded video that demonstrates a tremble (during a dry-run). What could have been the cause?

I was thinking of:

  • stepper motor issue (either the control, the motor itself)
  • the belt may be loose (but it also appeared on Z-axis movement too)
  • the wood has some inconsistency (but it also appeared on dry run)

Any idea how to debug this?

243aa8a532cd976f57a2f909911547ad.gif
243aa8a532cd976f57a2f909911547ad.gif854×480 256 KB

2

it seems motor(s) cannot handle existing acceleration and are losing steps instead. Try lowering it to less than half the current value.

3

What shall I tweak? Set something on the grbl?

4

If using grbl 0.9 https://github.com/grbl/grbl/wiki/Configuring-Grbl-v0.9

these are for acceleration
$120=50.000 (x accel, mm/sec^2)
$121=50.000 (y accel, mm/sec^2)
$122=50.000 (z accel, mm/sec^2)

5

I think it is 0.7 or something like that. But I assume it has similar setting. I’ll try that, thanks.

6

Are you able to move the gantry manually with the servo power removed? If you can’t move the machine manually with power removed, your machine can’t move the gantry with power.

7

Sorry, I didn’t offer a fix for this. If they don’t move freely; you probably have your eccentric nuts with the v-wheels too tight. I tighten mine until the point that it is hard for me to manually spin the wheel without moving the axis.

8

If trying to move it manually with power removed, I would add one thing… With Your Pinky

9

Thank you all the input! I’m able to move the gantry manually. I’ve lowered the feed rate and the acceleration too, and it looks much better (dry run only). I’ve realized that the g-code file had a feed rate of 6000, which may have been the root cause of my issue, but keeping the lower defaults anyway. Tomorrow I’ll give it a go with wood.

10

@Istvan_Soos 6000 might be a little too fast!

11

You should really update to 0.9 grbl. 6000 feed i could only accomplish with nema23 motors. With the original ones i reached up to 2000 but never higher.

12

I’ve edited the G-Code file to remove the “insane” feed rate, tuned down the defaults on the grbl, and I’ve got a wonderful cut (a small bear)! Thanks for the pointers, I’ll update my grlb version and experiment further.

13

@Istvan_Soos Thanks for the update! Glad people were able to help.