Getting back to a decent print - normal purge then air print for first layer!
 
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Getting back to a decent print - normal purge then air print for first layer!  

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Bruce Labitt
(@bruce-labitt)
Estimable Member
Getting back to a decent print - normal purge then air print for first layer!

I accidentally accepted the settings for someone's 3mf file to overwrite my settings in PrusaSlicer.  Since then (yesterday) I have not been able to get a successful print. 

Today, I selected the system preset for MK4 IS 0.4mm.  What I now see is z probing in the area of the print and then in the purge area.  Then it purges.  After the purge, the head slews and seems to scrape the bed to get to the printed piece area.  (That's not a good idea, is it?)  Then strangely enough, it starts to print the piece, but nothing comes out of the extruder!  So the print head does it's thing (perhaps a little low) and prints air. 

The MK4 used to print fine.  How do I get back to printing?  I don't care if I have to uninstall PrusaSlicer and blow away everything there, or reset the printer.  I do need to be able to print again.  Thanks for any and all help.

edit: First try the file was too big.  I zipped it and it is now 9.9MB.

 

Posted : 17/01/2024 5:52 pm
JP Guitars
(@jp-guitars)
Reputable Member
RE: Getting back to a decent print - normal purge then air print for first layer!

Here you go

https://forum.prusa3d.com/forum/prusaslicer/reset-slicer-to-stock/

Posted : 17/01/2024 6:57 pm
Bruce Labitt
(@bruce-labitt)
Estimable Member
Topic starter answered:
RE: Getting back to a decent print - normal purge then air print for first layer!

Is there an equivalent for the MK4 itself?  I can re-calibrate everything, the MK4 makes that easy.  It's just the factory reset, correct?

Posted : 17/01/2024 7:19 pm
JP Guitars
(@jp-guitars)
Reputable Member
RE: Getting back to a decent print - normal purge then air print for first layer!

The printer is irrelevant, it's the config in prusa slicer that needs fixing. 

Posted : 17/01/2024 7:22 pm
Bruce Labitt
(@bruce-labitt)
Estimable Member
Topic starter answered:
RE: Getting back to a decent print - normal purge then air print for first layer!
Posted by: @jp-guitars

The printer is irrelevant, it's the config in prusa slicer that needs fixing. 

Thanks.  I'll give it a try. 

There may be multiple issues, which makes it tough to sort out.  I'm beginning to suspect a thermistor problem, due to stringing, but I can't print anything at the moment!  An air print first layer is no good.

Posted : 17/01/2024 7:37 pm
Bruce Labitt
(@bruce-labitt)
Estimable Member
Topic starter answered:
RE: Getting back to a decent print - normal purge then air print for first layer!

Seem to be losing my marbles, or something...

  1. Selected the preset for MK4 IS 0.4mm nozzle. 
  2. Selected the Generic PETG
  3. Imported stl
  4. Flipped the part over to print properly
  5. Can't move the part from the center of the bed!  What is going on?  This used to work.  Even changing the coordinates doesn't work.  This worked yesterday!
Posted : 17/01/2024 7:52 pm
Bruce Labitt
(@bruce-labitt)
Estimable Member
Topic starter answered:
RE: Getting back to a decent print - normal purge then air print for first layer!

Deleted this instance of the slicer.  Installed a new one. 

Started over.  Inserted black PETG.  Something is wrong with the first layer - there is none.  The extruder seems to eject the filament rather than feed it.  I felt the filament and it was trying to eject it, rather than feed during the first layer!  The second layer and third seem to be fine, although things look hot.  It over extruded so much during the purge that it blobbed up the nozzle, and dragged junk along with it.  Nozzle is loaded with black filament.  This is no good.  It seems to be printing, but the glossy black looks frosted.  I will need to test the thermistor.  Might have to adjust the extruder - it's so weird it was running backwards during the first layer.

Had to pause the print to remove the big blob that was falling off the nozzle.  Why is it that the stupid nozzle moves far away from me, and stays so low?  Makes it hard to clean the nozzle.  Just getting frustrated, I guess.

Posted : 17/01/2024 8:34 pm
Bruce Labitt
(@bruce-labitt)
Estimable Member
Topic starter answered:
RE: Getting back to a decent print - normal purge then air print for first layer!

The thumb screws were both loose.  I snugged them up again.  Would that cause thermal or mechanical issues?  The thumb screws were initially tightened during the assembly.  Personally I don't like plastic thumb screws, they are hard to properly torque.  Have the same problem with an office chair, thumb screws never seem to stay in place.  I might replace the thumbscrews on the head with plain screws.  I have the bin full of hex keys nearby, so it isn't hard.

I will pull the print - it did complete - to my surprise.  Especially since there wasn't a bit of filament extruded for the first layer.  The print head would occasionally drip, but it didn't extrude at all for the first layer.  Partially through the second layer it started extruding.

Still don't know why the slicer won't reposition the stl file on the plate anywhere except the center, that's plain weird.

 

Posted : 17/01/2024 8:59 pm
JP Guitars
(@jp-guitars)
Reputable Member
RE: Getting back to a decent print - normal purge then air print for first layer!

Normally if you do a reinstall the configuration files remain on the PC. You need to either delete the dodgy configurations or switch to the standard configuration as described in the link I posted.

Posted : 17/01/2024 9:04 pm
Bruce Labitt
(@bruce-labitt)
Estimable Member
Topic starter answered:
RE: Getting back to a decent print - normal purge then air print for first layer!

I switched the configs the first time, and I got the same behavior.  Second time, I deleted all the configurations and installed the configuration through the configuration assistant.  Still can't move the part.  It lets me move, but it snaps back to the center, with either X or Y moves.  There has to be some check box that is set somewhere, that is wrong.

Looked at the part from the second time.  Really bad bottom layer.  Holes are almost completely filled in, and there is elephant footing.  I think it is running too hot, maybe because of the loose screws?  Or thermocouple - didn't even think to measure it when I installed it.

Posted : 17/01/2024 9:10 pm
miroslav.h4
(@miroslav-h4)
Honorable Member
RE:

 

Posted by: @bruce-labitt

 

Still don't know why the slicer won't reposition the stl file on the plate anywhere except the center, that's plain weird.

 

Check if you have Auto Centering turned on. Configuration -> Settings -> Auto Center Objects. Turn the option off.

This post was modified 10 months ago by miroslav.h4
Posted : 17/01/2024 9:16 pm
Bruce Labitt
(@bruce-labitt)
Estimable Member
Topic starter answered:
RE: Getting back to a decent print - normal purge then air print for first layer!

Thanks!  I just found that about 30 seconds before you posted this.

Posted by: @miroslav-h4

 

Posted by: @bruce-labitt

 

Still don't know why the slicer won't reposition the stl file on the plate anywhere except the center, that's plain weird.

 

Check if you have Auto Centering turned on. Configuration -> Settings -> Auto Center Objects

 

Posted : 17/01/2024 9:18 pm
Bruce Labitt
(@bruce-labitt)
Estimable Member
Topic starter answered:
RE: Getting back to a decent print - normal purge then air print for first layer!

I found the main issue.  It was those thumb screws.  They had loosened after four six hour prints.  Tightened the screws and everything seems a whole lot better.  I actually have a first layer!  It's like having a new printer. 😀   I will check the thermistor later, but at least this new print is behaving well - even the purge is better behaved.  So lesson learned - check your screws!

Posted : 17/01/2024 9:36 pm
ssill2
(@ssill2)
Noble Member
RE: Getting back to a decent print - normal purge then air print for first layer!

Glad you figured it out.  I had a problem like a month ago on one of my MK4s that the heatblock swiveled freely and this was causing me to have to up the temperature on that one to compensate, by like 10 deg for the same print, same material.  Another thing to watch for too.

Posted : 17/01/2024 10:10 pm
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