Mini nozzle crashing into parts during retracted (supposedly) travel
 
Notifications
Clear all

Mini nozzle crashing into parts during retracted (supposedly) travel  

  RSS
burtronix
(@burtronix)
Estimable Member
Mini nozzle crashing into parts during retracted (supposedly) travel

Hi all,

I think I figured this out on the Mini, but thought I'd report on it here in case anyone else has some insight or can benefit. I was printing some print-in-place linked parts with complex geometries & nozzle travel. I had been doing several versions successfully & changing the design. Suddenly on one of the versions the print started to crash in spectacular fashion, actually moved the spring-steel sheet off the heated bed. I caught it before it made a complete mess & there was no hardware damage. I thought it might be humid filament, so I dried a spool & tried again with the same results, but I caught it earlier. Even though I used a brim, I assumed that some of the parts came loose from the sheet & that's what got in the way of the nozzle travel. So I dried a different spool of filament that had printed successfully before, increased the brim width, & printed again while keeping a close eye on it. Then I heard it: not on every layer, but some of the long travel moves were crashing into a whole line of features on the parts as if it skipped a retraction before making the move. It made a zzzziiiipppp sound as it traveled from one corner of the bed to the other, hitting a line of little extended features along the way. This happened several times during a 5 hour print, but this time the sheet & brim held firm & the print was able to complete.

I went back & looked at the tool path on the 3MF, but couldn't see anything that looked like it might crash. Next I started to look here on the forums to see if anybody else experienced similar - didn't appear to be. Well, I decided to start my own thread to see if I could find some help, but I better get the Prusa Slicer & Mini Firmware version information. Hmmm - it turns out I'm not one, but two firmware releases behind. I'm used to Prusa Slicer telling me when the MK3S is due for a firmware upgrade. Doesn't it do the same thing for the Mini?

Tomorrow I'll give the print another go with the updated Mini firmware. Anybody have insight on this? Can out-of-date firmware result in a tool-path crash? I'll report back after trying the print again. BTW, here's the print that crashed:

https://media.prusaprinters.org/media/prints/46628/stls/464373_78300376-4fd3-435d-903a-2ce143b70906/mini-13-link-clasp-bracelet-v5.3mf#_ga=2.175019426.1898668679.1605642175-1359557180.1595519682

Whatever you find to do with your hands, do with all your might!...
Posted : 18/11/2020 11:08 pm
remotelove
(@remotelove)
Eminent Member
RE: Mini nozzle crashing into parts during retracted (supposedly) travel

Which firmware version are you running?  I did a quick scan of the firmware release notes and didn't see anything related to your problem.

Filament Settings -> Filament Overrides -> Lift Z may temporarily fix the issue.

I have rarely seen this problem but it can happen with the top and bottom layers in some cases that I have seen. Also, I am curious if this is just a simple slicer issue and not a firmware one. At your own risk, PrusaSlicer is up to 2.3.0-alpha3 ( https://github.com/prusa3d/PrusaSlicer/releases) which has addressed a ton of other issues but I don't see anything specific to your problem either.

Posted : 19/11/2020 9:32 pm
burtronix
(@burtronix)
Estimable Member
Topic starter answered:
RE: Mini nozzle crashing into parts during retracted (supposedly) travel

@derenma

I was on firmware 4.0.5, but today I upgraded to 4.2.1 & had the same issue. I think, therefore, it's a problem with the g-code out of Prusa Slicer 2.2.0. I'm trying to be a production shop, so I resist the urge to upgrade to alpha or beta releases.

I think I used the wrong term "retraction" on my previous message. I think what I meant was lift-z. I think that's usually used to address stringing, but I'm going to tweak it to see if it can eliminate these crashes. I'll still want to give feedback to the development team on git-hub. I'm wondering if there's anything to be found on the offending g-code? I haven't spent much time learning g-code, but I'm wondering if there's something specific I can search for that would indicate a crash condition (failure to lift z before a travel)?

Whatever you find to do with your hands, do with all your might!...
Posted : 19/11/2020 11:40 pm
remotelove
(@remotelove)
Eminent Member
RE: Mini nozzle crashing into parts during retracted (supposedly) travel

While this isn't your problem either, its a good start to investigating yourself: https://github.com/prusa3d/PrusaSlicer/issues/2709

Posted : 20/11/2020 12:29 am
burtronix
(@burtronix)
Estimable Member
Topic starter answered:
RE: Mini nozzle crashing into parts during retracted (supposedly) travel

For anyone who cares, here's my update to why the nozzle was crashing. It turns out that the model I was printing had a lot of small struts positioned at 45 degrees from the bed. Apparently, they were curling up due to warpage & crashing into the nozzle. So it was not firmware or some slicer defect. The solution is to print with an enclosure or a draft-shield.

Whatever you find to do with your hands, do with all your might!...
Posted : 05/01/2022 10:47 pm
Bern Statch
(@bern-statch)
Active Member
RE: Mini nozzle crashing into parts during retracted (supposedly) travel

So was it due to the ambient environment? I had a similar issue and I just needed to raise the temp by 10 degrees and it allowed for better layer adhesion but maybe an enclosure would of solved it as well...

Posted : 06/01/2022 2:35 am
burtronix
(@burtronix)
Estimable Member
Topic starter answered:
RE: Mini nozzle crashing into parts during retracted (supposedly) travel

It was a combination of ambient environment & thin strut design at 45 degree angle. My layer adhesion was already pretty good - so good in fact that on one attempt the crash moved the build sheet on my Mini instead of knocking the print loose.

Typically to reduce thermal warpage, you would reduce the bed temp, but that might result in worse adhesion.

Whatever you find to do with your hands, do with all your might!...
Posted : 06/01/2022 12:23 pm
Share: