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Build Plate Adhesion...Sometimes  

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jkoffman
(@jkoffman)
Eminent Member
Build Plate Adhesion...Sometimes

Hi all,

I've only recently started printing in PETG but so far I really like it. I've run into an interesting issue though, and I'd love some help trying to figure out why it's happening.

 

I designed a bracket to hold a small device. It's about 10cm x 6cm (from memory). It's not a solid, but there is a fair bit of build plate contact. I can print one just fine, repeatedly (I printed several versions as I was iterating the design). Once I was happy, I put 5 on the plate, sliced it up, and hit print. They printed, but I had more issues with bed adhesion. Warping, lifting, etc. This is using PETG on the textured plate. I wasn't watching that closely so I'm not sure exactly how far up it had gotten before warping, but I'd guess somewhere between 2-4mm.

 

I'm wondering if the issues I'm seeing have to do with how large each layer is when I'm printing multiple copies. When printing a single unit, the nozzle passes over each point more frequently than when it's printing 5 of them. Maybe that contributes to uneven cooling and then warping?

 

I should note that I also saw a possibly related issue on my PEI sheet using PLA on a large area print. I generally don't have any issues with adhesion on that plate at all.

 

Figuring out what causes this leads to the next question...how do I deal with this? Do I need to adjust the print bed temp? Keep the ambient temperature higher? Who knows! I can always fall back on only printing one at a time, but I do like understanding, then solving problems...

 

Any help appreciated!

Posted : 02/01/2021 11:29 pm
Area51
(@area51)
RE: Build Plate Adhesion...Sometimes

Most often adherence problems (and warping) is caused by a dirty build plate or bad z-calibration.

To make sure the textured build plate is clean, wash it in hot water and dish soap and dry it to avoid rust forming. Use a brush or a sponge to make it really clean. Don't touch the plate, except for the edges.

PETG likes a well calibrated z-level so be sure the level is right, run z-level calibration. I use a caliper to measure the thickness of the extrusion lines in the range of 0.13 -> 0.18 mm.

If your printer is located where there could be draft, try to shield off the draft. I have had prints failed due to draft from a window not fully closed.

If the print still fails, then it is time to look at other adjustments...

Have a look at my designs on Thingiverse or on PrusaPrinters ;)...
Posted : 03/01/2021 12:47 am
jkoffman
(@jkoffman)
Eminent Member
Topic starter answered:
RE: Build Plate Adhesion...Sometimes

@area51

I keep my plates very clear (alcohol), but that's a good point. I honestly never thought about measuring the z-level calibration, that's very smart! I will check it out.

The machine is close to a window, I think maybe I should block/insulate the back a bit to avoid drafts. I was curious about this, so thank you for mentioning this!

I appreciate the advice!

Posted : 03/01/2021 1:14 am
Area51
(@area51)
RE: Build Plate Adhesion...Sometimes

IPA will remove some dirt from the build plate, but not all. Hot water and dish soap is better at removing finger grease and sugar based dirt.

I went from using IPA to just washing my build plates as I have better results with washing. Just remember to give the plate a good dry to avoid rust forming - the printer is great for heating up the build plate and remove last traces of water.

Have a look at my designs on Thingiverse or on PrusaPrinters ;)...
Posted : 03/01/2021 3:12 pm
Peter M
(@peter-m)
Noble Member
RE: Build Plate Adhesion...Sometimes

Powder coated bed, clean with dish soap, dry plate(and use it so it can dry all the way), on the powder coated bed I usually go a little lower then on the pei sheet.

Extra could be glue stick, try different company's.

A big brim attach to model help.

Warping search on youtube for tips:

lower bed temperature,

lower first layer speed, to let model cool down.

First layer wider and/or  thicker is also possible.

This post was modified 11 months ago by Peter M
Posted : 03/01/2021 3:31 pm
jkoffman
(@jkoffman)
Eminent Member
Topic starter answered:
RE: Build Plate Adhesion...Sometimes

I will give that a try, thank you both for the tips!

I still think it's a bit weird that this problem only crops up only when I'm printing multiple copies of the same design. Single prints work fine, prints of 5 did not. I will try to re-clean and adjust my settings.

Thanks again!

Posted : 03/01/2021 5:18 pm
Area51
(@area51)
RE: Build Plate Adhesion...Sometimes

@jkoffman

It could be that the build plate is warmer at the center than at the perimeter (try raising bed temperature).

Or the bed is not leveled enough, using the 3x3 auto level - try 7x7 bed level setting in firmware).

Have a look at my designs on Thingiverse or on PrusaPrinters ;)...
Posted : 03/01/2021 5:24 pm
jkoffman
(@jkoffman)
Eminent Member
Topic starter answered:
RE: Build Plate Adhesion...Sometimes

@area51

Ah I didn't even know about 7x7 mesh levelling. I will give that a try next time I try this print. Might also tweak the bed temp.

Thank you!

Posted : 03/01/2021 5:34 pm
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