Notifications
Clear all

Object won't adhere to smooth plate (well enough)  

  RSS
NewReclaimer85
(@newreclaimer85)
New Member
Object won't adhere to smooth plate (well enough)

Dear Support,
i have the MK3s Plus. Since today I have the problem that the object will at some point lose adhesion to the plate.

I am printing using Octoprint.

I am cleaning the plate with isopropanol before each print.

It feels like the printer is doing a lot of quick y-axis movements. So the object will lose contact 'like cookies from the baking tray'.

It happens with gcodes that worked before a few days ago.

Do you have any advice to make it stay on the plate? Thank you.

Posted : 31/03/2021 6:39 pm
RH_Dreambox
(@rh_dreambox)
Prominent Member
RE: Object won't adhere to smooth plate (well enough)

If the part detaches from the bed, it is due to a contaminated bed or a too high Z level.
If the bed is contaminated with fingerprints, clean it best with warm water and detergent, wipe with paper.
You can use isopropanol (99%) for easier cleaning (I use it very rarely).

If your Z level is too high, there will be small gaps in the first layer.
Then lower the nozzle until the first layer is smooth and completely tight.

Bear MK3 with Bondtech extruder

Posted : 01/04/2021 10:32 am
Dan Rogers
(@dan-rogers)
Noble Member
RE: Object won't adhere to smooth plate (well enough)

And try adding a brim if your first layer is already perfect.  I have found that orientation on the bed for tall parts can limit the "shakes loose" issue (inertia is still in play, so shaking is a factor).

If your part is long and tall, and oriented along the X axis, reorient it along the Y axis (the shaking impact is less pronounced because you then pick up a lot of angular momentum that helps keep the part on the bed).

 

 

Posted : 01/04/2021 3:00 pm
bobstro
(@bobstro)
Illustrious Member
RE: Object won't adhere to smooth plate (well enough)
Posted by: @newreclaimer85

Dear Support,
i have the MK3s Plus. Since today I have the problem that the object will at some point lose adhesion to the plate. [...] I am cleaning the plate with isopropanol before each print.

This is typically due to poor adhesion resulting from some combination of print surface contamination and/or poor Live-Z (1st layer) calibration. It might be due to other issues, but it's a good idea to eliminate the basics before making printer or settings changes. You need to get a good first layer down as the foundation for your print in any case. Here's a big ol' info dump on the topic:

Your underlying issue is bed adhesion. Bed adhesion should be strong enough to hold the print flat and securely against  the forces of filament warping and nozzle friction. Filament should lay down cleanly on the PEI print surface and hold throughout the print.  If adhesion is poor, your print is likely to fail or have problems at higher layers. Common adhesion-related problems include:
 
  • Part warping or lifting along edges.
  • Bumping or knocking noises as the part moves under the nozzle.
  • Uneven vertical surfaces and bulges caused by print lifting and compression of overlying layers.
  • Spaghetti resulting from parts moving during printing.
  • The dreaded "blob of doom" caused by the part lifting and sticking to the nozzle as it extrudes filament.
 
There are 2 main causes of bed adhesion problems: cleanliness of the PEI print surface and Live-Z height adjustment. Even if you're dubious that these are the cause of your problems, they need to be addressed as 2 fundamental troubleshooting steps 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 a wash under the sink with Dawn is so effective: There's a much larger volume of Dawn-and-water attaching to grease and 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.
 
If, after doing all this, you still find narrow or tall parts popping off or warping you might try adding mouse ears to corners and thin parts,  adding a brim, or applying some additional adhesion booster to your bed. I'd go in that order for best consistency and ease of cleanup.
 
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.

It feels like the printer is doing a lot of quick y-axis movements. So the object will lose contact 'like cookies from the baking tray'.

It happens with gcodes that worked before a few days ago.

Do you have any advice to make it stay on the plate? Thank you.

Work through these just to eliminate obvious problems. If you still have problems, you can look at using adhesion enhancers, brims, increased bed temperatures, and reduce printer movement settings. It would be a shame to do that before you've eliminated the basics though.

 

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 : 01/04/2021 3:27 pm
NewReclaimer85
(@newreclaimer85)
New Member
Topic starter answered:
RE: Object won't adhere to smooth plate (well enough)

Thank you for all the responses. I did a lot of cleaning before and also the 1st layer calibration is fine (done multiple times). I guess I will do more cleaning, then.

Posted : 12/04/2021 1:36 pm
Share: