ASA print issue  

RE: ASA print issue

Only time I have seen something similar was when I had a crash. When it recovered, there was a Z offset.

It was driven by OctoPrint at the time.

Can't hurt to check your crash counter.

RE: ASA print issue

Thanks, but no, there was not a crash.  I am also printing directly from SD card.

This is reproducible too.  I have a second partially printed part that shows the same defect on the outside happening when the inside has a flat section.  The insides walls of the object look perfect, so I don't _think_ it missed any z steps.

The walls are plenty thick (5-10mm) that it shouldn't be bleed through the outer walls either.  There is plenty of infill space between the outer wall and the top that overlaps the inner wall.

I am wondering if the large inner flat area is shrinking and pulling the walls in a bit.  Maybe that tips the outer wall up just enough to either contact the nozzle, or bring the lower layer too close to the nozzle, so the lower layer is disturbed by the layer being deposited.

The part is making very good contact with the smooth PEI bed (too good, in fact, but that is a separate issue).  

RE: ASA print issue

Hi,

I've run to very similar issues this weekend. I'm trying to print part (tube 130mm diameter, 4mm wall, 30mm tall). Depending on layer height (0.15 or 0.2) always in the same Z position - like 3-4.5 mm before the top - the crash detection triggers and printer rehomes itself, causing always the same X layer shift of 1mm to the left.

I haven't found the root of this issues, so far from my experiments (the print takes 7,5h - and with a smaller print, I'm not able to reproduce this behaviour), the problem is always with ASA filament. 

I have printed a lot of these parts (exactly the same shape) from PLA (Prusament Galaxy Black) with no issue at all. Due to ASA prints, I've moved the printer into the enclosure for the first time. 

So far the statistics are:

1. ASA - Enclosure - 41 degrees - 0.15 layer, failed 25.20mm, X crash
2. ASA - Enclosure - the same as before
3. ASA - Enclosure - 41 degrees, 0.2 layer, failed 27.20mm, X crash
4. ASA - Enclosure - 41 degrees, 0.15 layer, FINISHED, crash detection turned off, minor layer shift almost in the same spot, but like 0.2 - 0.3mm to the side
5. PLA - Enclosure opened, 24 degrees, 0.15 layer, FINISHED
6. PLA - Enclosure - 33 degrees, 0.15 layer, in progress

The interesting part is attempt 1-4, seems to be somehow related to the time of print instead of height.

By discovering the point 4 - there is some kind of issue, so I suppose the Crash detection works fine, but ...

Consider everything around the printer as done (calibration, lubrication alignment, belt tension, ...). ASA is Fillamentum brand

RE: ASA print issue

Many threads about this issue.
https://forum.prusa3d.com/forum/original-prusa-i3-mk3s-mk3-how-do-i-print-this-printing-help/buldge-when-print-reaches-solid-layers/
https://forum.prusa3d.com/forum/original-prusa-i3-mk3s-mk3-assembly-and-first-prints-troubleshooting/getting-bulge-ridge-when-printing-large-flat-areas-that-are-walled-in/
https://forum.prusa3d.com/forum/original-prusa-i3-mk3s-mk3-assembly-and-first-prints-troubleshooting/need-help-not-sure-what-this-is-or-how-to-fix/
https://forum.prusa3d.com/forum/original-prusa-i3-mk3s-mk3-how-do-i-print-this-printing-help/layer-shifting-artifacting-or-something-else/

RE: ASA print issue

@neophyl

Thanks for thread refernces. Unfortunately none of these is the issue.

I suppose it is somehow related to the temperature after moving printer to the enclosure. I'll make more test prints (even ASA without enclosure) ad keep you posted. 

The problem is that test print with PLA in inclosure clogged the nozzle, so no test results available yet

RE: ASA print issue

@jan-p62

asking you to retry the print with crash detection off could be not a good idea for 7 hours print, could be?

Did you have chance to see the crash or you were reading only the last print report indicating crash detection?

Can ou pls. post a picture?

RE: ASA print issue

@zoltan

It won't be so daunting to run the print without crash detection. I did it already. The result was, a very minor shift (like 0.1mm) instead of 1mm shift with crash detection due to inaccurate X homing.

And yes, I witnessed the "crash", just set my timer to 6 hours, then sitting for 30 minutes watching the best 80k 3D TV (the enclosure doors) and the result was. Printer was finishing inner ring outer perimeter and suddenly CRASH (circular movement) - no idea why. But according to "no crash detection test" there is something happening but not so drastical. If there will be real crash (caused by part warping, etc.) the resumed print should crash again. I blame so weird error in electronics due to enclosure temperature.

Unfortunately I'm done with test prints for while, as I have discrovered testing the same print with PLA in enclosure wasn't the best shot I had to test - filament got melted by bondtech gear (not melted as from the nozzle) - I suppose the gears reached 60C which is glass temperature for PLA then filament string got softened and my force of the gear - squished to the inlet part of PTFE tube.

I've attached screenshot from slicer at the level where "crash" happend

RE: ASA print issue

I already saw few times the crash at certain level.

The X crash is identified when the X motor current overflows a certain threshold value by bumping to any obstacle or to increased movement resistance. In your case it happens at very similar height. According to the heights you indicated would be  interesting to look at the slicer ( better  probably into gcode) , what kind of movements the g-code is asking the printer to execute. Could be some weird movements combination like layer change (Z hop) with retraction + x move at the same time , which could initiate the crash. I do not think it is a false crash, because even with the crash detection switched off there is a very small scratch visible and which (when the crash detection is on) is due to the false homing multiplied.

I can´t believe that at that moment the filament works as a glue and for the short moment sticks the nozzle to the model or the nozzle is really bumping to the model due to a filament incorrectly laid down by previous layer. What is you printing layer ?

What is your seam set up ( defines where you ar changing layer) and retract set up? Are your X and Z rods enough perpendicular?

Can you share the result of the last XYZ calibration?

I would try to do a XYZ calibration and try to change the seam positioning. 

Crazy idea - try to print ASA with open enclosure 😎 

RE: ASA print issue

@zoltan

Hi Zoltan, thanks for your opinion! I've printed the same model with different layer heights (0.15 and 0.2) both "failed" at the same +- time ... which leads me to the time-related issue => in the fact of closed enclosure the heat build-up (i haven't checked the motor drivers temperature yet)?

Printing ASA without enclosure is definitively something on my list - but from the PLA failure, I need to reassemble extruder again => first I'll do MKR3S upgrade. Then whole XYZ calibration (after moving PSU out and installing surrogate support for the frame, I've checked perpendicularity by dial gauge - seems to be dead spot).

As soon as I have some updates, I'll update this thread. It is kind of interesting problem at all 🙂 Once again thanks for the support.

If there will be failures again, I'll move the control board outside the enclosure - but extending stepper cables will be kind of a "work". Front panel will go out then as well, due to resistance issues on 3.3V and some weird behaviours discovered around the forums with SD card read issue do to current drop over long cables ...

RE: ASA print issue

@jan-p62

Did u solve this issue? Today I was printing some ASA with the enclose closed and same thing every time, cash detected y axis....same part ever single time

Im printing the mk3 fan shroud and for some reason only happens on that stl file when I slice it in  PS. It's the one on the main prusa spare parts for mk3...not the 45 degree one that prints fine.... If I print just 1 of them it works ok..bit when I try 4 at once ...nope....crash detected....the first time there was a layer shift but then I took the y belt off, put back on, lines all the rods and ran self test fine.

Belts are good and in the range, it's the strangest thing that the one stl file screws up the mojo.

I also think it could be heat related, I couldn't touch the extruder motor due to the heat....

RE: ASA print issue

@islander2013

I'm not sure I've changed a lot of things in one shot. Extruder rebuilt, X-axis rods replaced (due to minor scratches), trying to keep internal temperature up to 40°C. Also installed extruder motor cooler - as it has been extremely hot (now without issues)

Similar to this one https://www.thingiverse.com/make:812025  

I've printed one spool of ASA so far with no problems, except the fan shroud sagging - this has been solved by reprinting fan shroud from PP. The main difference is the longest print took 3.5 hours, in the case of crashes above 6h+

In my case, the crash has always been on X-axis. If you're experiencing crashes on the Y-axis, check the perpendicularity of the rods and look for some scratches.

RE: ASA print issue

@jan-p62

never print PLA in closed enclosure, there is almost certain you will get heat creep. Hi ambient temperature makes the PLA soften at the etruder gears part and the crash is there. 

I haveprinted ASA without enclosure and without problems, of course ther  were no 6 hours prints.  What could help is an additional heatbreak fan, to reduce the filament melting at heatbreak area.

@islander2013

when you print in eclosure at high ambiente temperatures the stepper motor stallguard mechanism is more sensitive so you could encounter a false crash indication. 

RE: ASA print issue

@zoltan

what is an origin of PLA side note here? I thought we're talking about ASA prints 😉 Yes PLA in enclosure could be a problem if handled incorrectly. I'm printing everything enclosed due to fumes filtration. If you're able to keep the right temperature in your enclosure, you're fine even with PLA.

Anyway, the stall guard mechanism is an interesting point here. I've disabled crash detection for 2 of these prints, just to check for false triggers and in the +- same height there was barely visible layer shift, like a missed step on X-axis (in my case). From this observation, I assume the crash was triggered as it should. 

RE: ASA print issue

@jan-p62

it was a reaction on your sentence "but from the PLA failure, I need to reassemble extruder again => first I'll do MKR3S upgrade." Not sure how do you keep in enclosure the right temperature for PLA, but ambiente temperature 40°C and higher is not the best for PLA (heat creep) , and we have ancountered here a lot of troubles people printing with PLA in enclosure.

When you had crash detection on, did the printing head the home position move, to adjust the axes?

The layer shift with crash detection off can be due to a real crash.