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Removing extremely thin layer of PETG from powder coat bed  

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ryan.f15
(@ryan-f15)
Estimable Member
Removing extremely thin layer of PETG from powder coat bed

I had a print with an extremely thin layer of petg and I can't get this layer off.  What is the best way to get this off without damaging the bed?

Posted : 10/01/2020 3:49 pm
bobstro
(@bobstro)
Illustrious Member
RE: Removing extremely thin layer of PETG from powder coat bed

Print a thicker layer over it. If it won't remove easily, heat the bed up and go slowly.

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 : 10/01/2020 4:10 pm
Area51
(@area51)
RE: Removing extremely thin layer of PETG from powder coat bed

As bobstro suggest, print a ticker layer over the thinner.

To my experience PETG is easier to remove around bed temperature of 40C. A little IPA on the build plate will loosen the grip too.
No acetone on the powder coated bed as this will damage it.

Have a look at my designs on Thingiverse or on PrusaPrinters ;)...
Posted : 10/01/2020 4:51 pm
ryan.f15
(@ryan-f15)
Estimable Member
Topic starter answered:
RE: Removing extremely thin layer of PETG from powder coat bed

Ok.  Is there some way to print a thicker brim to prevent this in the future?

Posted : 10/01/2020 8:20 pm
vintagepc
(@vintagepc)
RE: Removing extremely thin layer of PETG from powder coat bed

I think the upcoming 2.2 slicer will have the skirt on top of the brim so increasing the number of skirt layers would give you something to grip...

Posted : 10/01/2020 8:25 pm
ryan.f15
(@ryan-f15)
Estimable Member
Topic starter answered:
RE: Removing extremely thin layer of PETG from powder coat bed

@vintagepc

That's great, but I still can't even get a normal print most of the time.....Here's the disaster that it did just now.  Given how much we are all paying for these printers, I'd expect it to at least work some of the time.

 

Posted : 11/01/2020 2:56 pm
fheatherz
(@fheatherz)
Eminent Member
RE: Removing extremely thin layer of PETG from powder coat bed

@ryan-f15

Yowsa! I would clean the bed if not done already and raise your Z - from that pic it looks way too low. Have never had these problems on the textured sheet - looks like new.. but squashing it in could cause this.. 

Posted : 11/01/2020 3:53 pm
ryan.f15
(@ryan-f15)
Estimable Member
Topic starter answered:
RE: Removing extremely thin layer of PETG from powder coat bed

I clean the bed, reset everything, nothing works.  You'd think for all the money that we spend on these things they'd actually get one that was working.  I repeatedly run into issues printing anything even slightly large, as you can see.  Here's the latest mess:

 

 

Posted : 11/01/2020 10:01 pm
rob.w5
(@rob-w5)
Trusted Member
RE: Removing extremely thin layer of PETG from powder coat bed

I had trouble like this for a while.  Let's see if you are having the same type of trouble I was.

Everything seems fine, you are getting a nice even layer, and then some strange lump or thread gets deposited on your print.  The next time your extruder goes over that position where the lump is, there's a thump as the extruder goes over the bump, or the extruder fails to continue moving, which gives you an axis shift.  Once that happens, game over.

In my case, I went to an outdoor supply shop and got a food dehydrator, cut the shelves out, and started drying my filament.  This should have made an improvement, but I didn't notice anything other than perhaps smoother surface.  How old is your filament?  What is the typical humidity where you live?

The huge change I made was taking the extruder completely apart and rebuilding it.  The only way I could see lumps being deposited that suddenly, especially at the beginning of a print is if the plastic was somehow able to squeeze through the threads in the heat block, and drip down the outside of the nozzle.  There are plenty of articles on how to assemble an extruder.  Look for them and follow their advice.  The one thing I did was use plumber's tape to increase the hydrolic sealing capability of the threads.  Since then I've never seen a blob drop on my print.  I have two Prusa printers.  One still has the extruder as received , the other, rebuilt.  Perhaps you have a leaky one.  Easily fixed if so.

Posted : 20/01/2020 2:58 pm
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