Trouble with PET after update to FW 3.7.1 and PrusaSlicer 2.0
Hello all. Recently, I updated to the new release of PrusaSlicer 2.0. In the process, I updated the firmware of my MK3 to the 3.7.1 release. Since then, I have been having a lot of trouble printing with PET, and I'm having trouble figuring out what the problem might be.
I'm using an i3 MK3 with the powder coated PEI bed, and some transparent Prusa PET. I have printed a lot of stuff with this spool before without any problems. After my recent updates, I re-sliced a model I have printed before and set it up to print while I was away at a friends house. When I got back, I had a total mess of plastic which had gotten all over my heat block. I cleaned this up as best as I could and tried again, but each time I tried I would run into trouble in the first few layers. Watching it work, it seemed like blobs we forming on the first layer which would eventually become so bad that the nozzle would start to run into them and rip the first layer up.
So, acting on the advice of a more experienced friend of mine, I disassembled the hot. I removed the heat brake and heat sink from the block and checked the end to make sure that there was no damage which might cause a gap between the nozzle and the end of the brake. I switched to a new nozzle, and cleaned up all of the burnt plastic on the block. During reassembly, I was careful to make sure that I had a good seal between the nozzle and the brake. To finish up, I added a silicon sock to the heat block and re-assembled.
I then re-calibrated the z-offset and the PID for the hotend. I also made some adjustments to the mesh bed leveling. Once everything looked good, I tried again.
I managed to get one print to succeed (yay!), but after that I seem to have returned to my original problem. Here is a photo of an attempt that I canceled as soon as it became clear that it was going to fail in the same way as before.
Note the small balls/blobs in the top middle of the brim of the print? The ugly main section of the actual model is just an extreme example of this. The issues start small, and then just get worse until you see the warping and damage in the middle of the picture.
This particular print was using a 0.15mm slice, but I have had similar issues at 0.1mm.
I have tried cleaning the bed, both with IPA and soap+water. I have tried both with and without gluestick. I have adjusted the tension on the bondtech gears, both tightening and loosening. The gears are aligned well. They were before, but I did double check. Nothing seems to make any difference.
Anecdotally , it seems like the new settings for PET which came with Slicer 2.0 are moving significantly faster than before. I wish I had kept either the old settings, or the gcode for the last time I printed this part, but I didn't 😣
Any ideas? I'll probably tear down the hotend again tonight to see if I have a gap between my nozzle and my heat brake (my friends theory). After that, aside from downgrading to either the 1.4 slicer, or an older firmware (or both), I'm not sure what to do.
Thanks in advance for any help/ideas!
Best Answer by bobstro:
[...] I then re-calibrated the z-offset and the PID for the hotend. I also made some adjustments to the mesh bed leveling. Once everything looked good, I tried again.
Looking at your picture, it looks like your Live-Z adjustment is so low that filament is being driven into the PEI print surface. Those blobs are forming as the nozzle literally scrapes filament off the print surface. Your Live-Z adjustment is very (very very) low.
[...] This particular print was using a 0.15mm slice, but I have had similar issues at 0.1mm.
In reality, the Mk3 will not let you get closer than 0.15mm to the print surface, but try using a 1st layer height 0f 0.20mm for good adhesion.
[...] I have tried cleaning the bed, both with IPA and soap+water.
What sort of soap are you using? Dawn dish soap is recommended (no vinegar or hand softener additives).
[...] Anecdotally , it seems like the new settings for PET which came with Slicer 2.0 are moving significantly faster than before. I wish I had kept either the old settings, or the gcode for the last time I printed this part, but I didn't 😣
Unless you went out of your way to delete them, your old custom configs should still be backed up as snapshots.
Any ideas? I'll probably tear down the hotend again tonight to see if I have a gap between my nozzle and my heat brake (my friends theory).
I wouldn't go to all that effort without trying Live-Z recalibration 1st. A gap between the nozzle and heat break usually results in a mess of filament oozing out rather obviously not out of the nozzle. Inspect your hotend and nozzle for such oozing.
After that, aside from downgrading to either the 1.4 slicer, or an older firmware (or both), I'm not sure what to do.
From what I can see of your picture, you just need to make some adjustments and calibration. I do find that I often have to recalibrate after updating firmware, and depending on what version you were on previously, this might be a good idea. I try to do it every time just as a precaution.
- Live-Z using Jeff's "Life Adjust".
- PID (temperature) tests to optimize printer performance for my regular print temperatures.
- Extruder correction. The Prusa ECOR tower tunes the extrusion rate to avoid moire effects.
- PINDA temperature.
RE: Trouble with PET after update to FW 3.7.1 and PrusaSlicer 2.0
[...] I then re-calibrated the z-offset and the PID for the hotend. I also made some adjustments to the mesh bed leveling. Once everything looked good, I tried again.
Looking at your picture, it looks like your Live-Z adjustment is so low that filament is being driven into the PEI print surface. Those blobs are forming as the nozzle literally scrapes filament off the print surface. Your Live-Z adjustment is very (very very) low.
[...] This particular print was using a 0.15mm slice, but I have had similar issues at 0.1mm.
In reality, the Mk3 will not let you get closer than 0.15mm to the print surface, but try using a 1st layer height 0f 0.20mm for good adhesion.
[...] I have tried cleaning the bed, both with IPA and soap+water.
What sort of soap are you using? Dawn dish soap is recommended (no vinegar or hand softener additives).
[...] Anecdotally , it seems like the new settings for PET which came with Slicer 2.0 are moving significantly faster than before. I wish I had kept either the old settings, or the gcode for the last time I printed this part, but I didn't 😣
Unless you went out of your way to delete them, your old custom configs should still be backed up as snapshots.
Any ideas? I'll probably tear down the hotend again tonight to see if I have a gap between my nozzle and my heat brake (my friends theory).
I wouldn't go to all that effort without trying Live-Z recalibration 1st. A gap between the nozzle and heat break usually results in a mess of filament oozing out rather obviously not out of the nozzle. Inspect your hotend and nozzle for such oozing.
After that, aside from downgrading to either the 1.4 slicer, or an older firmware (or both), I'm not sure what to do.
From what I can see of your picture, you just need to make some adjustments and calibration. I do find that I often have to recalibrate after updating firmware, and depending on what version you were on previously, this might be a good idea. I try to do it every time just as a precaution.
- Live-Z using Jeff's "Life Adjust".
- PID (temperature) tests to optimize printer performance for my regular print temperatures.
- Extruder correction. The Prusa ECOR tower tunes the extrusion rate to avoid moire effects.
- PINDA temperature.
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RE: Trouble with PET after update to FW 3.7.1 and PrusaSlicer 2.0
Looking at your picture, it looks like your Live-Z adjustment is so low that filament is being driven into the PEI print surface. Those blobs are forming as the nozzle literally scrapes filament off the print surface. Your Live-Z adjustment is very (very very) low.
Yup, that turned out to be the main problem. You are correct, Jeff Jordan's method makes it a lot easier to get stuff dialed in just right. Also, my bed leveling correction was off as well. That turned out to be important. I reset all of that correcting, then got the squares just to the point where they were showing the problem and backed off until the problem went away. At that point, there were still sections of the square (back left corner in my situation) where the lines were not fusing into a proper layer. At that point I used the bed leveling correction to fix this and now things are much better.
From doing some reading, I think I'll probably spend some time in the future attempting to mechanically level the bed, so that I don't have to use the software correction. For now, however, I'm just happy to be able to print again. I really want to print out the parts for my MK3S upgrade and get that done 😀
[...] This particular print was using a 0.15mm slice, but I have had similar issues at 0.1mm.
In reality, the Mk3 will not let you get closer than 0.15mm to the print surface, but try using a 1st layer height 0f 0.20mm for good adhesion.
Yes, this is the default in Slicer for the first layer as well. I was just referring to the settings I had for subsequent layers, my first layer was set to 0.2mm. Sorry about that, I should have been more clear.
[...] I have tried cleaning the bed, both with IPA and soap+water.
What sort of soap are you using? Dawn dish soap is recommended (no vinegar or hand softener additives).
ya, name brand dawn.
[...] Anecdotally , it seems like the new settings for PET which came with Slicer 2.0 are moving significantly faster than before. I wish I had kept either the old settings, or the gcode for the last time I printed this part, but I didn't 😣
Unless you went out of your way to delete them, your old custom configs should still be backed up as snapshots.
So, I managed to figure this one out as well, and fixing it probably helped a great deal as well. At some point in time during this process, the top level speed adjustment override got set to 150%. I'd like to blame the firmware update, but it is much more likely that this was just pilot error. I never really use this feature, so after I had accidentally got into this situation, I just didn't notice for a long while.
From what I can see of your picture, you just need to make some adjustments and calibration. I do find that I often have to recalibrate after updating firmware, and depending on what version you were on previously, this might be a good idea. I try to do it every time just as a precaution.
- Live-Z using Jeff's "Life Adjust".
- PID (temperature) tests to optimize printer performance for my regular print temperatures.
- Extruder correction. The Prusa ECOR tower tunes the extrusion rate to avoid moire effects.
- PINDA temperature.
So I had done the PID calibration already, and #1 along with fixing my speed issues have gotten me back into a good place. After I get my home maintenance projects moved along (want to keep my boss happy), and my hotend updated to the MK3S, I will probably return to #3 and #4, as well as exploring some of the mechanical bed leveling options.
TL;DR? You were dead on with your answer. Thanks a lot for the help!
RE: Trouble with PET after update to FW 3.7.1 and PrusaSlicer 2.0
I found some time ago that sometimes after a FW upgrade, I would get strange behaviour.
This always vanished after a full reset and re-initialisation as per a brand new printer.
https://help.prusa3d.com/article/SYvbQ66IXF-factory-reset
Yes it takes some time, but sometimes it is necessary. I have no proof, but it almost looks like the flash memory boundary gets moved between FW updates, yet the old data is not cleared, so your new FW could end up with garbage data where it is expecting nothing.
A full factory reset (All Data), does just that, clears ALL DATA.
So basically, flash your new FW, then do a full factory reset then run through the initialisation routines, calibration, PID tuning, Live-Z, Mesh bed levelling adjustments etc.
It's worth keeping a notebook to hand of any settings made and if you have modified the printer as you may have different extrusion settings etc which will all need to be re-entered.
Normal people believe that if it ain’t broke, don’t fix it. Engineers believe that if it ain’t broke, it doesn’t have enough features yet.