Layer Shift Detection Not Working  

Re: Layer Shift Detection Not Working

had layer shifting occur a couple of times was using shipped firmware 150.

thought i was going nuts that i was the only person with this issue.
first thing i did was tighten all the pulleys.

after reading all the threads on the layer shift;

i upgraded to newest firmware and turned crash detection off, crossing fingers for the future.

there is obviously still a ways to go with the firmware and fixing bugs.

Re: Layer Shift Detection Not Working

Just a quick thought on layer shifting issues. Whilst I await my MK3 to be delivered, I do have some experience with the TMC2208 drivers as a retrofit onto a K8400. https://forum.vellemanprojects.eu/t/tmc2100-drivers-on-k8400/14610/8
One of the things I found they tended to do was to skip steps if:
• Any of the hardware was not perfectly aligned and smooth like butter to move with the belts off.
• Drivers pushing too high a current to the motors
• Not enough cooling of the driver chips
I found them to be so fussy, I've put them on the back burner and saving them for a rebuilt K8400 project in the future.

Now it is quite likely there is still a weird bug in the Marlin firmware where crash detection is causing skipped steps. It is worth just bearing in mind these other three causes however, rather than just blaming bugs in the code.

The running current - on the MK3 that is set in software with the Einsy board, so we cannot mess with that too easily. What we can look at is hardware alignment and cooling. What I have seen from the build instructions - there is a right rats nest of wires in the box housing the Einsy PCB. Whilst the Trinamic drivers sink most of their waste heat into the PCB, if there is poor ventilation over the top of any of the Trinamic chips where cable management is poor, this might just be "the straw that broke the camel's back" and cause the driver to momentarily reset on thermal overload. Something so simple to check, simply by moving some wires around for optimum ventilation.

When I do get my MK3, I'll be getting the Flir thermal imaging camera out to see how hot the drivers are getting - more to satisfy my own curiosity 😀

it shouldn't' skip in spread cycle.... i run 2100's and 2130's without issue on other machines with repetier and reprap firmware. i don't use skip detection or anything but they run fine. i also ran them without heat sinks. they get hot but looking at the datasheet, they can get fairly warm before there are issues. i added heat sinks anyway but who knows, could be thermal with all the wires. hard to say. maybe it's not enough current....

Re: Layer Shift Detection Not Working

Hey guys, I'm super new to 3D printing so forgive me if I'm wrong in assuming I have the same issue as you?

Images here:

https://imgur.com/a/bVRfj

I'm trying to print this lamp shade: https://www.thingiverse.com/thing:730263

I've tried twice now and it's failed around hour 12 or 13 (of 20) each time in the same way. Is this layer shift?

I have a Mk3 ordered assembled from Prusa.

Any help appreciated!

Re: Layer Shift Detection Not Working

Look bit more like the filament extruded in those layers got weird. Was the head moving slow though there?

Re: Layer Shift Detection Not Working

It was the middle of the night so I didn't actually see it - but it was a stock Prusa Slic3r settings (I think no more than 60mm/s).

I'm running the print again at 90mm/s and it has got past that part this time, but still there is a big blob/band at the same point all the way around so something isn't right.

Thanks for your input !

Re: Layer Shift Detection Not Working

I've updated my firmware and it seems to work better, I'll try some more this weekend to see more thoroughly but i managed to print a 10 hour print with crash detection on and no layer shifts. I thought I had the latest firmware but I noticed that they released one the same day my shipped so i definitely didn't have that update.

Re: Layer Shift Detection Not Working

Ok, I've tested some more. weird though. I tried to reslice the benchy and printed again to be sure nothing was wrong with the gcode, but i got the same results as before, for some reason when i turn crash detection it works fine but with it the problems come back, but it worked with another model. so it does seem to be a bit geometry related i suppose since the ofther model was more of a rectangle

This model worked flawlessly with detection on:
https://www.thingiverse.com/thing:925556

Re: Layer Shift Detection Not Working

I'm on the latest firmware, and have just had 2 different prints in a row layer shift at the same spot with the printer showing a 2-3 y crashes for that print. Checking the timelapse it doesn't seem to actually be hitting anything. I'm trying the last one now with crash detection turned off but not other changes to setup to see if it resolves it.

Re: Layer Shift Detection Not Working

Print just finished with crash detection disabled, came out perfect.

Re: Layer Shift Detection Not Working

Check GitHub - https://github.com/prusa3d/Prusa-Firmware/releases/tag/v3.1.2-RC1

Note the first item is this our layer shifts being addressed?

3.1.2 - RC1 firmware for Prusa i3 MK3
Summary:

accurate sensorless rehoming for crashdetection and powerpanic
extruder multiplier precission fixed
fan checks synchronization

Detailed description of changes:
Accurate sensorless rehoming for crashdetection and powerpanic

In previous version rehoming was not accurate and some small layershifts could appear in case of detected crash or power loss recovery. For proper function of accurate rehoming implemented in current firmware version it is required to re-run selftest.
Extruder multiplier precission fixed

In previous firmware version, there was inaccuracy in counted E coordinate in case that extruder multiplier was set with M221. For 50um layers, the precision loss led to holes in the print.
Fan checks synchronization

In previous firmware versions checking for fans were not properly synchronized with planned moves. Printing using very low speeds and long linear movements could led to false fan errors in some cases. This has been fixed in current firmware version.

Re: Layer Shift Detection Not Working

It sure does look like it! I have to try it out as soon as i get home 🙂

But i-m not sure though since it seems to sense crashes that has not happened.