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lorin.kobashigawa
(@lorin-kobashigawa)
Active Member
Can't print triceratops

I am having trouble printing the triceratops sample.  After playing with the first layer calibration tool, I've been able to print the flat Prusa logo ok.  When I print the triceratops, the first layer seems to go down, but then the second layer doesn't stick to it, and eventually gets tangled up on the extruder.   I've tried adjusting the extruder idler tension and the 1st layer z offset, but it doesn't seem to help.  Any ideas on what I have calibrated wrong?  This is with the z-offset from the first layer calibration tool set to .925.  I also tried .940 but then the first layer curled up at the edges instead of laying flat.

Using the prusament filament that came with the printer.

Napsal : 27/05/2019 10:11 pm
toaf
 toaf
(@toaf)
Noble Member
RE: Can't print triceratops

maybe wash the print bed with soap and water in a sink. 

 

almost looks like your first layer can use some work.  but that could be a sticking to the bed issue.

I had a hell of a time printing supports when I started.  clean bed fixed that issue I think, if I remember..

I have a Prusa,therefore I research.

Napsal : 27/05/2019 10:30 pm
lorin.kobashigawa
(@lorin-kobashigawa)
Active Member
Topic starter answered:
RE: Can't print triceratops

thanks for the help!  Ok, i've tried cleaning with soap and water, then wiping it off with 91% alcohol before printing.  Based on some other forum responses, I also tried sanding the surface with 1500 grit sandpaper, then wiping it down with alcohol, but still same result, after the first couple layers the extruder starts picking up some of the filament and then pretty soon there's a big clump of filament attached to the extruder going around pulling up big chunks.

 

 

 

Napsal : 28/05/2019 2:15 am
toaf
 toaf
(@toaf)
Noble Member
RE: Can't print triceratops

 its hard to see the first layer. I don't think it can hurt to go another 25 lower -950 -975. worth a shot you should notice on the first few layers if its correct. I only wash with soap, I don't use ipa anymore.

I have a Prusa,therefore I research.

Napsal : 28/05/2019 2:42 am
bobstro
(@bobstro)
Illustrious Member
RE: Can't print triceratops
Posted by: lorin.kobashigawa

thanks for the help!  Ok, i've tried cleaning with soap and water, then wiping it off with 91% alcohol before printing.  Based on some other forum responses, I also tried sanding the surface with 1500 grit sandpaper, then wiping it down with alcohol, but still same result, after the first couple layers the extruder starts picking up some of the filament and then pretty soon there's a big clump of filament attached to the extruder going around pulling up big chunks.

Go slow. One step at a time. If you are having adhesion problems, it's important to understand that these can be caused or aggravated by two factors that need to work together well for successful prints. Start with a thorough bed cleaning and stop there. The Dunk with Dawn is the most effective cleaning measure, and nothing else should be needed as bed prep. Use isopropyl alcohol and acetone only between prints after the bed may have been fouled and you just can't get it to the sink for a dunk. Save any abrasives for "nothing else works" situations only. Here's mama's tried and true copypasta recipe to get you going. 

You are having bed adhesion issues. PLA should lay down cleanly on the PEI print surface and hold throughout the print. There are 2 main causes of bed adhesion issues. Even if you're dubious that these are the cause of your problems, they're 2 fundamental troubleshooting steps you need to complete to rule out the basics:

  • A dirty PEI print surface. Even if you don't think this is the cause, it's always a good idea to make sure your PEI surface is clean before trying any other fixes. Take it to the kitchen sink and give it a good dunk with Dawn (original formula, no vinegar or hand softener variants) dishwashing soap or your local equivalent (e.g. Fairy in UK). Use a clean paper towel to clean it off, and another to dry it. Avoid using any sponge or cloth that has been in contact with grease. Above all else, avoid touching the PEI print surface. Once it's good and clean, you should be able to use 91%+ isopropyl alcohol between prints, 100% acetone when that fails, and another dunk when acetone fails. Worst-case, use a 3M 7445 ScotchBrite pad or equivalent to give it a very light buff, but only infrequently.
  • If you have not already done so, try using Jeff Jordan's "Life Adjust" procedure for calibrating your Live-Z setting. It is much easier to use and understand than the on-board routine. In general, start high (less negative) and work lower (more negative) in large increments (e.g. 0.1mm) until the filament starts to stick on its own. When it's right, you should be able to gently rub it without it coming loose. Then start lowering (more negative) the level until there are no gaps between layers. When you've got your Live-Z setting adjusted properly, you should be able to gently rub the extruded lines without dislodging them. 
And above all else, avoid touching the PEI print surface.
 
Try those 2 steps. If you're uncertain of the Live-Z results, post pics here of the 75x75 print bottom and you'll get quick help. 
 
In the future, a good dunk with Dawn will restore both sides of your to like-new condition and is always a good thing to try when you encounter 1st layer problems. 
 
If you want more detail, I've consolidated my notes on Prusa PEI adhesion, bed cleaning, and Live-Z calibration. I've done a brain dump on nozzle sizes as well.
My notes and disclaimers on 3D printing

and miscellaneous other tech projects
He is intelligent, but not experienced. His pattern indicates two dimensional thinking. -- Spock in Star Trek: The Wrath of Khan

Napsal : 28/05/2019 3:52 am
btrigg se líbí
lorin.kobashigawa
(@lorin-kobashigawa)
Active Member
Topic starter answered:
RE: Can't print triceratops

Thanks!  I didn’t mean to imply I did all those cleaning steps at the same time, I did IPA, then acetone, then soap&water, then soap&water + IPA, then 1500 grit sanding + IPA.

I used the dish soap I had on hand, so will pick up some dawn tomorrow.

Will also try going lower on the z-axis adjustment.

Napsal : 28/05/2019 5:53 am
bobstro
(@bobstro)
Illustrious Member
RE: Can't print triceratops
Posted by: lorin.kobashigawa

[...] Will also try going lower on the z-axis adjustment.

Definitely try the "Life Adjust" method of Live-Z calibration that I linked to. It's much easier to use and understand than the on-board routine. The pictures are unfortunately so small I can't gather much from them, but there's a good chance that you're too low already and the nozzle snagging filament is part of the problem. Start high -- way high if necessary -- then work lower (more negative) in big increments until the filament starts to stick to the point that you can poke it and it'll stay put. Then work successively lower until the gaps between layers disappear. That's when you've got it nearly perfect.

My notes and disclaimers on 3D printing

and miscellaneous other tech projects
He is intelligent, but not experienced. His pattern indicates two dimensional thinking. -- Spock in Star Trek: The Wrath of Khan

Napsal : 28/05/2019 6:21 am
lorin.kobashigawa
(@lorin-kobashigawa)
Active Member
Topic starter answered:
RE: Can't print triceratops

Thanks!  The Life Adjust was a huge help. I re-set my PINDA probe, and then did the life adjust, and think I have the z-adjust correct now.

  • 85 v 115: 85 big gaps, 115 small gaps
  • 130 v 160: 160 lots of pilling felt rough, 130 felt smooth, tiny amount of pilling
  • 120 v 140: 120 felt smooth, no pilling, 140 felt a little rougher, moderate pilling

I am now re-printing the Triceratops at -0.120 z-adjust and 75% speed.  It is going much better, but there's still a lot of strings in part of the print, is that to be expected?

Life Adjust Output

 

Triceratops after several layers:

 

Napsal : 29/05/2019 5:14 pm
lorin.kobashigawa
(@lorin-kobashigawa)
Active Member
Topic starter answered:
RE: Can't print triceratops

The infill on 3dBenchy is also kind of messy.

Napsal : 29/05/2019 7:13 pm
--
 --
(@)
Illustrious Member
RE: Can't print triceratops

See image for an example of a dirty bed (click to zoom). Using alcohol after soap and water simply moves oils from your fingers back to the bed unless you're using gloves, thus soap and water is the LAST step in the cleaning process. 

What nozzle and filament type are you using?  And, have you ever changed the nozzle from the original brass 0.4mm ?  It looks like you are dripping melt here and there, often caused by a improperly tightened nozzle.  This can also explain some of the other print problems you are having.

 

Sorry to hear someone talked you into ruining your bed by sanding. 

This post was modified před 5 years by --
Napsal : 29/05/2019 7:23 pm
lorin.kobashigawa
(@lorin-kobashigawa)
Active Member
Topic starter answered:
RE: Can't print triceratops

Ugh.  I am a total moron.  I thought all the filament I had was PLA, but after all my troubleshooting, I happened to take a closer look at the filament and discovered I had accidentally ordered one spool of PETG.  So I've been trying to print PETG on PLA settings this whole time.  

Thank you so much to everyone who responded!   The 'life adjust' process is a great help.

🤦‍♀️

-Lkb

Napsal : 29/05/2019 8:23 pm
toaf
 toaf
(@toaf)
Noble Member
RE: Can't print triceratops

ouch, hey it happens. at least the spool was labeled correctly.

I have a Prusa,therefore I research.

Napsal : 29/05/2019 9:20 pm
bobstro
(@bobstro)
Illustrious Member
RE: Can't print triceratops
Posted by: lorin.kobashigawa

[...]I happened to take a closer look at the filament and discovered I had accidentally ordered one spool of PETG.  So I've been trying to print PETG on PLA settings this whole time.  

I'm impressed it printed as well as it did. I was trying to put my finger on what those blobs looked like and "PETG" is the answer. I had some struggles with it starting out. Hopefully that'll be the worst of it.

Don't forget to clean out the PETG before switching back to PLA lest you get a clog. I like to do a cold pull with eSun cleaning filament when switching back to PLA. At the temps you used, it may not be an issue, but harder-to-melt filament in the nozzle or hotend can cause under extrusion.

My notes and disclaimers on 3D printing

and miscellaneous other tech projects
He is intelligent, but not experienced. His pattern indicates two dimensional thinking. -- Spock in Star Trek: The Wrath of Khan

Napsal : 29/05/2019 10:02 pm
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