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Matto
(@matto)
Eminent Member
Bed cleaning question

I'm having a recurring issue with PETG adhesion.  I have figured out how to fix it, but I am curious if there is something else I should be doing.  I've been running this printer for 1 month and 4 days, so I am still relatively new to this generation of printer. 

I am using both the Prusa textured sheet and Thekkiinngg textured sheet, and I am getting similar issues with both. 

Procedure:

1) I clean the sheet with 99% medical grade IPA with a sponge

2) I allow the sheet to dry

3) Without touching anything but the edges, I mount the sheet and print

4) Print done, I take the print off and reclean with IPA.

This works several times.  No issues.  Then, eventually, I have a print that won't stick.  I'll fiddle with dropping the Z, usually causing the print to rip off because the Z is too low. 🙂 

Then, I will clean the steel sheet with soap and water (again with a sponge), dry it with paper towels, then heat it up immediately to make sure all the water has evaporated.  It will then print just fine for the next few prints, back to normal.

The guidance for both sheets says to use IPA only to clean.  However, this is NOT working after several prints.  The sponge I am using is just the "smooth" sponge.  Should I be using something more abrasive when I clean?  

NOTE: I adjust Live Z with the "Life Adjust" method.  I've printed out many squares!  I do not think Z height is the inherent issue here, as I can print both obviously too low and obviously too high and get the adhesion issue.  

Thank you,

 -Matt

 

Stock Prusa MK3S+ built from kit on 12/2020
OctoPrint, typically print from a drybox, no enclosure yet
Printing proudly since 2011...
Posted : 29/01/2021 2:17 pm
Peter M
(@peter-m)
Noble Member
RE: Bed cleaning question

Clean bed with dish soap, use a lot of hot water, and do this a few times.

Then adjust your z, this needs to be perfect, otherwise the print will release.

Make picture of your first layer, then the forum could look at it.

Cleaning bed, cleaning in between use alcohol, use 90 or 98 %, and use a lot of alcohol, and use a new paper towel every time, otherwise it will not clean.

Cleaning and the first layer are the most important for 3d printing, and it prevents the model of sticking to the nozzle in a long print.

Pictures of failed prints could help.

Posted : 29/01/2021 9:35 pm
Terry
(@terry-8)
Active Member
RE: Bed cleaning question

@peter-m-3

I'm a beginner and after cleaning it and using alcohol, I found that only two things worked:

1. lower the Z, and

2. use gluestick... lots of it!

Posted : 29/01/2021 10:37 pm
Peter M
(@peter-m)
Noble Member
RE: Bed cleaning question

@terry-8

if you have sticking problems, clean with dish soap, use a lot of hot water.

After all works again you can use alcohol again, but use a lot of alcohol wen you clean, after a few prints clean again with dish soap.

And it depends on what you are printing, if I want maximum adhesion I do clean with dish soap, big brim, glue stick, bed hotter, first layer hotter, first layer slower, etc.

Posted : 29/01/2021 10:50 pm
ssill2
(@ssill2)
Noble Member
RE: Bed cleaning question

@peter-m-3

After working over a couple days with @swiss_cheese,   I 100% agree with the dish soap.   I am using Dawn Platinum with water and a standard dish sponge, the abrasive side.  After that, dry and spray original windex on it and use a paper towel loosely to get the bubbles off, but leaving a layer of windex.  This will dry as soon as you put it on the printer.   As swiss_cheese explained it, this is not for adhesion but for removal.

Importantly, be sure your zOffset is right. in my case I was WAY off and that's why I ended up in the predicament I was in with tape + glue etc.   In my case, I was using zOffset of -0.043 when the actual number FOR MY PRINTER was -0.298.  I had changed all kinds of settings to get good adhesion and it was all unnecessary.

With zOffset right, I didn't have to have a big fat first layer(.8 was was I was using),  just went with default 0.45mm wide.   No glue required!

It sticks great and comes off easy too.  Note, the windex is for PETG only.  Since I gained this new knowledge I've not yet tried to print PLA or TPU again, but I plan to rework all my profiles for those now that my zOffset is right.   

Posted : 31/01/2021 3:15 pm
Matto
(@matto)
Eminent Member
Topic starter answered:
RE: Bed cleaning question

@peter-m-3

Thank you, this was helpful.  Turns out my particular frustration yesterday had nothing to do with Z or bed cleanliness.  My silicon sock had shifted and I was printing filament around the heatbreak.  Filament was extruding partially.  Really incredible actually.  It was laying down a pretty decent first layer through a non-aligned sock and nozzle.  Fortunately I don't run unattended and caught it pretty quickly.  

The general issue remains, and I think the answer is to just use soap and water from time to time.  There isn't much to take a picture of once it no longer sticks to the textured sheet.  I notice it right away when the skirt fails to stick and as soon as the nozzle makes the first 90 degree turn and it drags the skirt around the bed.  I've been using a sponge with IPA and I wonder if that is part of the problem.   It is certainly an issue of getting the bed clean, as soon as I use soap and water it fixes it every time.  

  -Matt

Stock Prusa MK3S+ built from kit on 12/2020
OctoPrint, typically print from a drybox, no enclosure yet
Printing proudly since 2011...
Posted : 31/01/2021 3:34 pm
ssill2
(@ssill2)
Noble Member
RE: Bed cleaning question

In my case I only use the PEI sheet since I want the smooth surface.  I'll have to defer to others with more experience on using the textured sheet.  I do have one but I've not used it.

Posted : 31/01/2021 5:10 pm
cwbullet
(@cwbullet)
Illustrious Member
RE: Bed cleaning question

The keyword is sparing.  I have used it for both the smooth and textured.  It is not recommended for the textured but it will reset the surface if you can't get anything to stick.  

I start with n escalation of forces type of approach:

  1. Alcohol: I use it every few prints.  I use 91% or better isopropyl alcohol.  I spray it on a cool bed and let it sit for 10-15 seconds and wipe it off with a lint-free towel.  Once in a while, an alcohol rinse is helpful to remove PLA residue. It does not remove finger oils as well as soap and water.
  2. Dish soap and water:  Alcohol doesn't clean the body oils off the bed; soap and water do. I prefer Dawn dish soap. Wash the bed in hot water, use a fresh paper towel as a washcloth, with a few drops of plain dish soap.  Rinse well in hot water - if you have very soft water, rinse a bit longer.  If you are going to scrub the surface, use a non-scratch sponge. Try with a lint-free towel.  
  3. Acetone wash: Use very, very sparingly and it should be used only when you considering throwing it away (end of life).  This should be a last resort if you are considering tossing and replacing the surface.  Do not under any circumstances soak the surface.  Pour a 1-2 cm puddle of acetone on the bed.  Spread it around with a fresh paper towel.  It will evaporate fast as you clean.  You do not want to leave it on there long.  This step removes PEI oxides that form over time.   It will improve PLA adhesion to a like-new state.  I have 10 printers that use textured and smooth sheets.  I have done this 4 times with great success in 3 years.  This should what I mean by sparingly.   

I do 1 and 2 every week.  #3 have done only 6 times on two different sheets in 3 years.  I own 12 Prusa machines so I think you get the point.  They were troubled from the start and it worked at resetting them when I consider tossing them.  

--------------------
Chuck H
3D Printer Review Blog...
Posted : 01/02/2021 3:17 am
FEW and Matto liked
Matto
(@matto)
Eminent Member
Topic starter answered:
RE: Bed cleaning question

All,

  So, I think I have fixed my bed cleaning issue.  I spent time watching and evaluating what I am doing and have come to the conclusion that the problem is without a doubt ME!  It is almost certainly my own finger oils that are not being removed particularly well with IPA.  Things I used to come to this conclusion:

1) I started cleaning my sheets: Smooth, Textured, and Thekkiinngg textured with dawn dish detergent.  I have zero adhesion issues when I do this.  In reality, Smooth+PLA always sticks pretty well.  PETG on the two textured is the bigger issue (understandably). 

2) I then stopped cleaning between every print with dawn and wear thin plastic gloves when handling the sheets and removing prints.  I also have zero adhesion issues.  I've been using IPA as others do between prints and this is working great.  No adhesion issues.

So, in conclusion, I believe my hands are the culprit.  Apparently my ability to gently pry parts off with my fingernails and not touch the sheet is miserable. 

NOTE: Don't pick up a hot print bed with thin disposable plastic gloves.  The melt!

 -Matt

Stock Prusa MK3S+ built from kit on 12/2020
OctoPrint, typically print from a drybox, no enclosure yet
Printing proudly since 2011...
Posted : 12/02/2021 4:13 pm
ssill2
(@ssill2)
Noble Member
RE: Bed cleaning question

@terry-8

I've only been printing a few months also and had the same problem and I resorted to using super wide extrusion widths and painters tape + glue.

In the end that was all wrong lol

With the correctly calibrated zOffset,  in my case -0.365 for PLA and -0.243 for PETG, I have no need of any adhesives anymore.  I've been printing for a couple weeks now without issues.

The above suggestions of dishsoap(I'm using dawn platinum) and a scrub with hotwaterare spot on.

Simply scrub, dry with a paper towel.  For PETG, spray original windex on there and wipe the excess off, leaving a thing wet layer which will quickly dry.  This helps with release of PETG from the plate after printing.   I do this before each print and where I was using tape + glue, I use nothing at all.  The upside is you get a nice smooth bottom on your print too.  If you've been printing with wrong settings you'll likely have to recalibrate with the new Zoffset.  I did.   but I found once I recalibrated, one profile worked for most PLA and one worked for most PETG.  Instead of having one per vendor+filament type combination!

Posted : 13/02/2021 3:41 pm
ssill2
(@ssill2)
Noble Member
RE: Bed cleaning question

I will say that after printing TPU(Ninjaflex) again this morning that I do feel a thing layer of glue is a good idea when printing TPU.  I felt it stuck a bit too well with windex.   With the glue it came off pretty easy.   I had to add a 3rd zOffset to the mix with the Ninjaflex as the PETG setting seemed to be have as if it was too close.  FWIW

Posted : 13/02/2021 7:10 pm
Robin
(@robin)
Estimable Member
RE: Bed cleaning question

For the record: I print PETG on the textured sheet all the time and clean it before every print and before heating with lots of isopropanol and a fresh paper towel. With lots I mean: spraying it on the bed until it's completely wet.
Until now I had no issues whatsoever, never had to use anything else like acetone... - but Chuck has probably more hours on his steel sheets. 

If at first you don't succeed, skydiving is not for you....
Posted : 13/02/2021 10:07 pm
cwbullet
(@cwbullet)
Illustrious Member
RE: Bed cleaning question

@robin

It helps, but you will start having problems after 1-2 years fo printing.  

--------------------
Chuck H
3D Printer Review Blog...
Posted : 13/02/2021 10:14 pm
stewartr
(@stewartr)
Eminent Member
RE: Bed cleaning question

@cwbullet

I totally agree.

I give my sheets a spray of IPA before every print and wipe it down with a paper kitchen towel. Very occasionally I use soapy water, but I try to avoid touching the print area with skin at all. I also wipe the back-side of the sheet, and print bed, with the same towel just to remove anything that might be there (bit of plastic etc.). I use acetone incredibly rarely.

Posted : 14/02/2021 1:47 am
cwbullet
(@cwbullet)
Illustrious Member
RE: Bed cleaning question

@stewartr

Yup.  Eventually, every sheet has adhesion issues.  In my experience, you start with poor adhesion.  Typically, adhesion increases over the life of the sheet until it is not worth keeping or it pulls the surface off.  I have been able to extend the life with Windex or another release agent.

--------------------
Chuck H
3D Printer Review Blog...
Posted : 14/02/2021 1:58 am
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