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At the end of the lines it stands out  

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BFreakout
(@bfreakout)
Active Member
At the end of the lines it stands out

Hello Community,

I have a MK3S + and have done some great printing. As of today, however, it has started to stick out slightly at the end of lines. For the test, I also made the calibration print. This one is also terrible, although I haven't changed anything on the device.

I used PLA..

What can that be? How can I fix that?

Thanks in advance and best regards

Posted : 08/01/2021 6:21 pm
bobstro
(@bobstro)
Illustrious Member
RE: At the end of the lines it stands out

You've likely got issues with bed cleaning and/or Live-Z adjustment. Here's an info dump that should get you going...

Your underlying issue is bed adhesion. This is a common problem that can be caused or aggravated by two factors that need to work together well for successful prints.  Filament should lay down cleanly on the PEI print surface and hold throughout the print. There are 2 main causes of bed adhesion issues: PEI cleanliness and Live-Z height adjustment. Even if you're dubious that these are the cause of your problems, they're 2 fundamental troubleshooting steps that 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. If it's a smooth PEI sheet, 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 (1200-1500 grit) pad or equivalent on smooth PEI to give it a very light buff, but only infrequently. If you've got a textured powder-coated PEI print surface, the official instructions are to use 91%+ isopropyl alcohol on it only. Rumors persist that some have had good luck getting started with these sheets by giving them a wipe with 100% acetone and a dunk with Dawn. Either way, there's no real warranty on these sheets. YMMV.
  • 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 onboard routine and much easier to make mid-print adjustments accurately with. 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 you've got your Live-Z setting adjusted properly, you should be able to gently rub the extruded lines on the PEI surface without dislodging them.  Then start lowering (more negative) the level until there are no gaps between layers. You should not be able to peel the lines apart after printing, but the top should be regular. 
 
Remember that the effectiveness of a solvent such as isopropyl alcohol is going to depend on concentration and volume relative to the amount of grease you're trying to remove. 71% pads work... on very tiny amounts of grease. A squirt of 91% works better, but if there's a lot of grease, you need a lot more alcohol. This is why the wash under the sink with Dawn is so effective: There's a much larger volume of Dawn-and-water rinsing stuff away instead of just moving the broken-down grease molecules around.
  
And above all else, avoid touching the PEI print surface.
 
Glue stick is NOT necessary for PLA on the PEI print surface. You paid the big bucks for a Prusa with a removable spring still sheet with PEI, so clean it up and take advantage of it. Save the glue stick for printing sticky stuff like PETG that might adhere too well. Even then, I only find I need glue stick when printing high-temp PETG at 260C+ temps.
 
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. If you want more detail, I've consolidated my notes on Prusa PEI adhesion, bed cleaning, and Live-Z calibration
 
A bit of trivia - The reason higher concentrations of alcohol seem to be harder to find is that isopropyl alcohol is most effective against bacteria at roughly a 71% concentration. A bit of distilled water helps slow evaporation, making the alcohol more effective. If you're looking in pharmacies, that's why 91% and higher seem to be hard to find.
 
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...
Posted : 08/01/2021 6:36 pm
JoanTabb
(@joantabb)
Moderator
RE: At the end of the lines it stands out

Perhaps that's the problem, maybe you need to change something, 

1, is the build plate perfectly clean> 
2, Are you using 7x7 Mesh bed levelling? 
3, I suggest you use a different first layer configuration tool, the prusa one is not very good 

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

as you use a printer the nozzle is likely to wear, the bearings are likely to settle in, and the print surface is likely to pick up contaminants. 

I use hot water and dish soap, wash really well, rinse well and dry immediately, then I use the build plate with no other Surface preparation 

regards 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 : 08/01/2021 6:36 pm
BFreakout
(@bfreakout)
Active Member
Topic starter answered:
RE: At the end of the lines it stands out

I have now cleaned the bed again properly with water and it probably actually helped ...

really strange, I had cleaned it beforehand with window cleaner and then with disinfectant ... nevertheless the errors came ...

now i had rinsed it and then only treated it with window cleaner .. works as if nothing had happened ... without calibration ..

Thank you very much for the quick help

Posted : 08/01/2021 9:09 pm
bobstro
(@bobstro)
Illustrious Member
RE: At the end of the lines it stands out

Try using ONLY dish soap/washing-up liquid and water. Use a lot of hot water. Do NOTHING ELSE and avoid touching the print area. Any disinfectant or window cleaner is likely to leave residue that will REDUCE adhesion. This can be handy when printing overly-sticky filament like PETG, but you don't want it for PLA.

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...
Posted : 08/01/2021 9:22 pm
Peter M
(@peter-m)
Noble Member
RE: At the end of the lines it stands out

Window cleaner will leave a residue behind , and pla will stick not as good.

Window cleaner you should use with the pei sheet and with petg printing, The windows cleaner layer will let petg not stick to hard.

For pla use dish soap, every few prints, between use alcohol(use a lot). For prints with small foot print or big flat models, always clean with dish soap, and if needed use glue stick.

first layer calibration, is important, look on youtube how deep you need to go, to low is not good, model can come loose higher up in the print.

Posted : 08/01/2021 10:31 pm
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