PLA Adhesion, wider Extrusion not overlapping and regular curling in one corner
 
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PLA Adhesion, wider Extrusion not overlapping and regular curling in one corner  

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armer_geddon
(@armer_geddon)
Eminent Member
PLA Adhesion, wider Extrusion not overlapping and regular curling in one corner

Hi,

i am fairly new to 3D printing and my new Prusa MK3S is only the second printer I have worked with so far. I am impressed with the overall quality and ease of use, and have been printing without major issues aside from PLA not really sticking to the textured sheet in the beginning, which I was able to improve drastically with the dishsoap approach (I know it you are not supposed to use water on the textured sheet, but just IPA would not do the trick). However the adhesion is still not perfect with PLA, I am printing some boxes without top and bottom right now, which are 80 mm high but have a wall thickness of only 6.7 mm, which is of course not ideal in regard to warping. To help with the adhesion I added a brim of 7  mm and changed the width of the extrusion to 1 mm for the first layer. This produces usable prints, but sometimes there are still some corners lifting.

What is really curious to me, is that I always get curling in regular Intervalls in the front right corner of the box, as can be seen in the attached picture. The first curling starts always at a height of about 12 mm, the following ones always at a distance of 18 mm. This does seem too regular to me to be caused by the corner lifting from the print bed, also it does really only affect the corner like it was slightly to hot while printing.

The second issue is the overlap of the wider extrusions of the bottom layer: The lines of the brim are only slightly touching and come apart quite easily in most cases. The bottom of the box does look better, I suppose those lines get squished together by the following layers. Is there Anything I can do to enhance the overlapping, aside from adjusting the Z-offset or the extrusion multiplier? I spent quite some time to get the height of the first layer height right, because of the adhesion issues in the beginning, going so far to lower the nozzle so far that the nozzle dug trenches in the filament and turning it up until that just stopped, but maybe I still didn't get that right. But if I did, would that leave me with the extrusion multiplier as the last option to increase the overlap? If so maybe I should try to print some kind of calibration cube and see if it should be adjusted, but the overlap was fine with a lower extrusion width.

Any tips and ideas would be much appreciated!

This topic was modified 4 years ago by armer_geddon
Posted : 01/12/2019 1:13 pm
JoanTabb
(@joantabb)
Veteran Member Moderator
RE: PLA Adhesion, wider Extrusion not overlapping and regular curling in one corner

Hi, 
Are you using 7x7 mesh bed levelling?
have you tried a bed temp of 70C?

 

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 : 01/12/2019 11:42 pm
armer_geddon
(@armer_geddon)
Eminent Member
Topic starter answered:
RE: PLA Adhesion, wider Extrusion not overlapping and regular curling in one corner

Hi,

Thanks for the quick reply! I did already switch to 7x7 mesh bed leveling, and I raised the first layer temperature to 65C while leaving the other layers at 60C. Would you advise me to increase just the first layer temperature to 70C or rather keep it constant for all layers?

Posted : 02/12/2019 12:37 am
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 --
(@)
Illustrious Member
RE: PLA Adhesion, wider Extrusion not overlapping and regular curling in one corner

Poor adhesion is almost always a result of fingerprints and related oils on the bed; so a deep clean in soap and water at a sink is needed (alcohol doesn't clean well because most folk simply do not use enough to do a good rinse with it).  So a 3 gpm sink faucet with hot water is useful.

 

Posted : 02/12/2019 1:40 am
armer_geddon
(@armer_geddon)
Eminent Member
Topic starter answered:
RE: PLA Adhesion, wider Extrusion not overlapping and regular curling in one corner

I already did clean the bed multiple times with hot water and soap, because of the initially very poor adhesion and was careful not to touch the print surface after that. That did help tremendously and most PLA parts stick and print just fine right now, but the curling, especially in the front right corner appears every time I print the box (about 10 times until now). I'm not entirely sure, if the curling is an adhesion problem, because it even occurs if the corner is not visibly lifting. It could of course be, that I still was not generous enough with the hot water and dish soap, but I am starting to wonder if something else could be the issue here, like not enough cooling. Maybe it is the unfavorable shape of the box, being as tall as it is with the small footprint on the bed, or the sharp 90 degree angle which will never print perfect, even if I got the maximum adhesion achievable with the textured sheet. Or something entirely else, which I am not aware of. I am thinking about aquiring the smooth PEI sheet as well just to rule out the adhesion, because Prusa states in the description, that maximum PLA adhesion is achieved with that sheet.

But before that I will give it another try with increasing the temperature to 70 C for the first layer and another trip to the kitchen sink as suggested 😉

This post was modified 4 years ago by armer_geddon
Posted : 02/12/2019 6:37 pm
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(@)
Illustrious Member
RE: PLA Adhesion, wider Extrusion not overlapping and regular curling in one corner

I think you are calling the seam locations "curl" ... which it isn't.   Try changing the seam location from nearest to aligned or read, and see if that "fixes" or affects what you are concerned with.

 

There is no curl here:

This post was modified 4 years ago by --
Posted : 02/12/2019 9:09 pm
armer_geddon
(@armer_geddon)
Eminent Member
Topic starter answered:
RE: PLA Adhesion, wider Extrusion not overlapping and regular curling in one corner

Well, I already did some research on 3D printing, but obviously not enough, as I was completely oblivious to the existence of seams - shame on me. Thank you very much for clearing that up for me, it does make a lot of sense now that I know about it 😀. Also increasing the bed temperature as suggested did help with the bonding of the brim, so thanks for that as well, all my worries have been adressed 😊.

 

Posted : 03/12/2019 11:27 pm
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