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First Layer Fine....apart from supports  

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jesterminute
(@jesterminute)
Active Member
First Layer Fine....apart from supports

So I've successfully printed a few smaller things and I'm broadly happy that things are setup (calibration, z value etc) correctly.
HOWEVER....

Trying to print a Hyperpixel Square Prusa front end (for my Rasp Pi 4) and I appear to have an issue whereby all (most) 'normal' first layer stuff goes down well -except- the support strands which look like they're lifting each time the nozzle shifts or moves.

I have :

  • washed the plate lightly with soap and water - dried it
  • cleaned it further with Isoprop Alcohol - let it dry
  • there are no scratches or anything on the plate
  • Most recent print i tried the glue stick stuff that came with the printer.
  • nozzle should be pretty clean, not having any excess issues

Settings are (in multiple prints) : 

  • Prusa MK3S
  • Filament - PETG FilamentPM
  • Tool: Have tried settings between 235-240 (as per FilamentPM spec)
  • Bed: Tried settings between 80 - 90
  • 0.4mm nozzle
  • Mesh Bed Levelling is on 7x7
  • Most recent print i dropped the speed down to 60% there was some improvement on the brim but no improvement on the supports
  • Could anyone advise how I can troubleshoot this problem (I don't yet have the 'knowledge/language' to be able to search effectively for a solution - aka do we call this 'lifting' or something else)

    The frustration is that I've successfully printed a few smaller items and they look great. Now randomly i'm failing to get the first layer supports down despite doing soap & water + alcohol as a second run. Hence i'm wondering if, because the other ones didn't need supports, if i'm missing something.

 

 

 

 

Posted : 31/08/2020 1:19 pm
GKMAKEIT
(@gkmakeit)
Estimable Member
RE: First Layer Fine....apart from supports

What is all the white stuff on your build plate, it doesn't look clean?

Posted : 31/08/2020 1:24 pm
jesterminute
(@jesterminute)
Active Member
Topic starter answered:
RE: First Layer Fine....apart from supports

@gkmakeit

That time around it was the glue stick - didn’t particularly make any difference in terms of those support bits

Posted : 31/08/2020 2:44 pm
GKMAKEIT
(@gkmakeit)
Estimable Member
RE: First Layer Fine....apart from supports

@jesterminute

Ah I should have known that. I’ve never used glue so it didn’t registering my mind. How’s your first layer calibration?

Posted : 31/08/2020 2:53 pm
jsw
 jsw
(@jsw)
Famed Member
RE: First Layer Fine....apart from supports
Posted by: @jesterminute

@gkmakeit

That time around it was the glue stick - didn’t particularly make any difference in terms of those support bits

I'll make another call-out for the Layerneer Bed Weld adhesive.  It really helps on those small first layer supports.  No more turned-up ends.

It's not a substitute for cleaning the plate, but it sure helps when that first layer just does not want to stick.

Posted : 31/08/2020 2:57 pm
jesterminute
(@jesterminute)
Active Member
Topic starter answered:
RE: First Layer Fine....apart from supports

@gkmakeit

I’d say first layer calibration is pretty good - I found it much easier using a 3x3” square to properly nail it. I doubt I’ve got it perfect (I’m a newbie after all) but it’s smooth with no blemishes and doesn’t lift.

 

@jsw will check it out. Cheers. Feels like a settings or process thing in my case but doesn’t hurt to have a look at that also

 

 

Posted : 31/08/2020 3:19 pm
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 --
(@)
Illustrious Member
RE: First Layer Fine....apart from supports

Cleanliness is crucial. Here's a "perfectly clean bed" after a considerable 99% alcohol wash:

A few minutes at the sink with hot soapy water and the next print succeeded.

Posted : 01/09/2020 8:37 am
jesterminute
(@jesterminute)
Active Member
Topic starter answered:
RE: First Layer Fine....apart from supports

@tim-m30

Yup, i've gotten pretty religious about doing the soapy water thing, I'll give it another go and post up pics if there's any difference this time.

Assuming Alcohol _after_ washing with soapy water is the correct SOP (or is it better to not?)

Posted : 01/09/2020 9:43 am
Neophyl
(@neophyl)
Famed Member
RE: First Layer Fine....apart from supports

There should be no need to use IPA after a clean with detergent.

Posted : 01/09/2020 10:06 am
--
 --
(@)
Illustrious Member
RE: First Layer Fine....apart from supports

@jesterminute

As Neo has said, absolutely NO alcohol after a soap and water wash.

Alcohol has basically left my maintenance routines except for after acetone rinses, just before I go to the sink.

I think alcohol works only if you have very dry skin or use rubber gloves, and a huge ultra clean lintless cloth to soak things up as you rinse with it. Otherwise, it does an excellent job making a molecular thin layer of oils on the bed (and if your fingers are damp with alcohol as you are wiping, that's just adding more oil to the bed, too).

Posted : 01/09/2020 6:10 pm
jesterminute
(@jesterminute)
Active Member
Topic starter answered:
RE: First Layer Fine....apart from supports

Sure enough - washing with soap and water but -not- cleaning with alcohol seems to have solved most, not all of my issue.

I also slowed the first layer down to 60% and increased the bed temp from 83 to 88 (I don't know if that helps i was just 'feeling' my way around the problem)

Enough that I could get the print done (winner) but I'm still getting slight lifts (might be the wrong term - small 'tufts' of filament, maybe only 1-2mm tops) on certain angles or when it moves suddenly to print elsewhere. Can happen on first layer but also on subsequent layers.

In most cases it was able to print over the lifts (it passed over them okay) or I'd move a strand out of the way.

I know there's a filament retraction setting (which i'm not yet confident enough to play with/stray from default) - are there any other settings (like heat/speed etc) that would also help me lessen the random blobs?

Again I -think- i have my z levels set well enough (certainly the test calibration prints look good)

Posted : 02/09/2020 9:21 am
jesterminute
(@jesterminute)
Active Member
Topic starter answered:
RE: First Layer Fine....apart from supports

(edit : and i should say "thank you for your help thus far, it's really appreciated - the thing that's making conventional searching hardest is learning the technical language")

Example attached.

Z setting looks fine (I think. certainly the 3x3 calibration pattern looks really nice and smooth)

Speed @ 80%

PETG

Temp : 235 on bed, 86 on nozzle

 

This post was modified 2 years ago by jesterminute
Posted : 02/09/2020 9:28 am
Neophyl
(@neophyl)
Famed Member
RE: First Layer Fine....apart from supports

Those circular holes arent sticking very well at all so adhesion is still a problem. 

One other thing you can alter (but isnt related to the holes) is you have the brim configured but you havent adjusted the skirt distance to be outside of the brim.  So the skirt is cutting the brim area.  Id place it 1-2mm outside it. 

You can see where this is causing you issues as there are gaps.  The filament from those gaps is I suspect accumulating on the nozzle (as petg loves to stick to the nozzle) and then at later points is dropping off leaving blobby strands around the print.

Posted : 02/09/2020 10:18 am
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