Help Please! First Layer Issues?  

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Jeff
 Jeff
(@jeff-14)
New Member

Hello all. I have now had my Prusa MK3S now for about a month with no prior experience in 3D printing. Things have been going great and I've been learning a lot over these past few weeks and have run into my first issue I can't figure out. For the past 3-4 days, all of my prints fail, come off the print bed, and I end up with the 'spaghetti monster.' Here are some more details:

 

  • PLA
  • First layer 215, remaining 210
  • Print bed have tried between 60-65
  • Print speed have tried 100%, 75% for the first layer, and 75% for entire print
  • Cleaned external nozzle (haven't taken apart to check for clog)
  • I clean the print bed with 91% IPA after every print and have done some extra cleaning given the recent issues
  •  

Based on the above, the next thing I tried was doing the first layer calibration (note I ordered the printer as an assembled unit). Given my lack of experience, I could be way off but I think this may be where my issue is since mine doesn't look like any of these first layer. Here are a few pics of mine: pic 1, pic 2, pic 3

 

So here's the thing, since it doesn't look like any of the examples, I have no idea how to interpret these results, other than based on the middle section and underside, it seems something is wrong. I haven't adjusted using Live Adjust Z yet as I didn't want to mess with it if in fact it is correct and my issues are being caused by something else. 

 

Based on the pics, is it probable that my issues are caused by the nozzle being too far/close and thus I need to adjust my Z? Or should I try increasing the first layer print temp to maybe 225, or setting the skirt distance to 0 mm, or adding a brim? I've considered these but can't get past the results of the first layer calibration.

 

And my apologies, I realize this is probably something easy to address and rudimentary, but I've been struggling with it for several days now and would appreciate some experienced insight.

Posted : 04/12/2020 4:41 pm
jsw
 jsw
(@jsw)
Noble Member

It looks like you're using the textured sheet.  How are your results using the stock smooth sheet?

Also, what brand/type of filament is in the photos?  Have you tried a Z calibration using the included Prusa silver-gray PLA?

Posted : 04/12/2020 5:43 pm
Jeff
 Jeff
(@jeff-14)
New Member

Thanks @jsw. So am I using the stock smooth sheet. I was getting the same print failures regardless of the filament brand but all the filament I've used to this point has been PLA and either the included Prusa silver-gray, Hatchbox, or Sunlu. 

 

I just went back and did another Z calibration using the Prusa silver-gray PLA, and then another first layer calibration. Here are the results of the first layer calibration using the Prusa silver-gray PLA with pictures of my print bed beforehand pic 1, pic 2, pic 3, pic 4, pic 5

 

You'll see in the pics that the calibration didn't actually fully print. Very different results from the other PLA in the previous pictures. Does this mean its the z calibration or an issue with the bed leveling? When I looked into the bed leveling earlier, I didn't do it based on the warning at the top of the article bed leveling. What would you recommend trying at this point?

Posted : 04/12/2020 7:17 pm
jsw
 jsw
(@jsw)
Noble Member

It looks to me like the Z is too high.

I would suggest that instead of the internal calibration routine, you try any of various Z calibration test prints.  There are several in the Prints section.  I like the one that has a 9 square array (below) and all of the squares should be smooth and solid.  This will test the Z calibration overall and if some squares are good and others are not, you can do an advanced calibration and adjust left/right front/rear to compensate.

Posted : 04/12/2020 11:02 pm
Peter M
(@peter-m)
Noble Member

Yes you need to adjust the  " first layer calibration", this needs to be done, and you need to learn this.

Every steel plate is different, temperature can be different, filament can be different.

Here is a movie on how to:

 

Most important to 3d print is:

1. Clean bed, use dish soap, and a lot of hot water, alcohol does not clean of everything.

2. First layer calibration needs to be 100%, adjust this for every print if needed, yes you need to check this.

Both settings are needed to get sticking to the bed on highest level.

Also check wen first layer is ready, if layer is good and sticking good, and no holes between lines. Or a little bubble wen it is releasing.

 

Pei steel sheet,  clean with dish soap, then pla will stick good. If you use petg on pei sheet, use window cleaner to spray on pei bed, petg will destry bed because it will stick to much. Or use glue stick.

Powder coated bed, this is ideal for petg, only clean, and print. A few times I use alcohol to clean(use a lot of alcohol), then clean with dish soap, and dry plate on printer(print immediately to dry).

Pla on powder coated bed is possible, but not easy, it will release fast. Use a big brim attach to model, first layer 5 or 10 higher temp, bed temp for the whole print 10 higher, use glue stick if needed(is a lot better). I am now printing small parts  with pla, I placed models close together, so the big brim makes it one big part on the bed, so model can not release, and I use glue stick.

This post was modified 6 months ago 3 times by Peter M
Posted : 05/12/2020 11:51 am
Jeff
 Jeff
(@jeff-14)
New Member

@jsw and @peter-m-3 thank for very much for the help and insight! here's where I'm at and a couple follow up questions.

 

I started by cleaning the steel sheet really well. Then I the built in Z calibration test. @jsw I couldn't find the exact calibration test with the 9 squares and connecting lines (if you have a link that would be great) so I printed this one test 1, test 1.1, test 1.2. After this one it seemed to me I still needed adjustment. Then I printed the one in the video @peter-m-3 test 2, test 2.1, test 2.2. I felt like I was good to go after this one. My Z levels: -1.028 (as received), -0.800 (after built in Z test), -0.900 (after test 1), -0.940 (after test 2). I know this is meaningless as everyone's is different. So I went ahead with a test print of benchy and BAM, printed!!! Are there any glaring adjustments I still need to make based on the benchy print benchy, benchy 2, benchy 3, benchy 4?

 

So I have some follow-up questions.

 

  1. How often do you clean the steel sheet with soap/water?
  2. Assuming the Z level of -0.940 is correct, a) can I assume this to be the Z level for all prints done with this specific spool of filament, or b) do I need to do a Z calibration test before every print even if using the same spool of filament? If a), can I set Z level for specific filament spools in PrusaSlicer, or would I just keep a notebook with brand, filament type, color, spool #, and Z level? If a) is not appropriate and I need to do a Z calibration test before every print, would I need to go through all 3 or just go through them until I'm comfortable with the Z level?

 

Thanks for the help!

Posted : 06/12/2020 2:25 pm
JoanTabb
(@joantabb)
Moderator

Hi Jeff, 

sorry I am late to the party!

does your printer test nine points duting mesh bed levelling (3X3), or does it test 49 points (7X7)

If it's not testing 49 points, I would suggest you turn this on using the LCD Menu

what are you using for the live Z calibration, the Prusa First Layer Calibration tool is a bit crap, in my opinion. 

I use   this process

https://forum.prusaprinters.org/forum/original-prusa-i3-mk3s-mk3-assembly-and-first-prints-troubleshooting/life-adjust-z-my-way/

it might help you

as far as washing the bed is concerned....      I find it initially needs a damned good wash, rubbing in all directions with plain dish soap and hot water, using a new dish sponge so you know there is no grease on it, rinsing with hot water, and drying with plain paper towels, 
Once you get the filament sticking, as long as you don't contaminate the buildplate with finger grease or dust etc. you don't need to wash it again for ages...    I DO NOT use IPA....   even the 99.9% Lab grade IPA I have seems to leave the surface worse than soap and water

Some folk suggest that the IPA takes your finger grease and transfers it to the build plate...    I have not tried wearing nitrile gloves, because soap and water works for me.

Also consider raising the bed temperature, if you are using PLA...  I use 70C,,, a recent roll of (Sunlu?)PLA Suggested 80C for the bed 

Good Luck, 
Joan

I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK...
Posted : 06/12/2020 2:52 pm
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