Hello All, Went 0 for 6 today trying a 3D carve,

Hello All,

Went 0 for 6 today trying a 3D carve, about halfway thru the program it loses track of position and things get weird

2x it happened in the same spot and I opened up the junction deviation to 0.010 from 0.002"…Thought I had it but it will not complete the 2MB G-Code successfully.

Can anyone who has root caused this behavior before please provide some avenues to debug - I am a CNC noob

JSON1.92
TinyG440.20
Win7 x64
OX CNC belt drive

First guess is your stepper drivers overheat and shutdown on and off and you lose steps. Or your pulleys are loose and steps are lost. Does the Gcode stop executing? I’m guessing Gcode keeps running fine you just lose position on spindle head which is steppers shutting down.

Thanks John,

I’ll inspect stepper drive temp during my next run on Wednesday. Didn’t seem too warm but maybe there are some maneuvers that produce heat quickly. My current trim is set on the lower half of the adjustment range

The Gcode keeps running but the machine becomes lost.

I’m also going to break down my Gcode into steps and try that, if nothing else I’ll be able to pinpoint the path deviation a little easier…hopefully

Machine got lost in Y direction today when only running straight X cuts. No stepper heat on Y.

Gcode continued to run, problem occurred halfway thru a 2hr cut

Is there a tool or test to split ChiliPeppr from TinyG issue?

How’s the coupling from the stepper to your belts? If gcode kept running and you kept getting coordinates back from TinyG that sounds like mechanical

All couplings are tight and set screws showed no witness marks of relative movement relative to the stepper shaft.

I ran (2) 2hr session last night with great success, I set the machine to 1/2 speed (30"/s) and the roughing pass depth to 1/2 as well (0.060").

This may indicate hardware loading is an issue. I believe I will replace my 32T stepper drive sprocket with 20T and re-evaluate

Thanks for the comments and help.

Perhaps you aren’t pumping enough current into your steppers and thus they are simply missing steps due to being too weak?

I will try turning up the current trim. I tuned them by “ear” but in a free run state only.

They are set at about 1/2 way, very close to tinyg factory default

3.0Nm stepper, 8 wire, bi-polar parallel arrangement, 2.8A max

For ChiliPeppr, there’s no way a different file extension would influence anything.

I just had this happen again, it seems like Gcode from Easel is fine but from Fusion360 is not fine…about halfway thru the job it just wants to draw a circle

Happened twice (at the same spot) with different current trim and microstep settings.

I’ll dig around Fusion forums and see if there’s related material