Cura setting(s) to stop brim curling off the build plate?

[Bumbletoon 0]

I'm having an issue with PEI build plate adhesion for a particular PLA that may just be garbage; Sunlu clear orange and opaque purple. PLA has been dried and print area moisture is about 20%.

 

Prints initially adhere fine and then seem to suffer acute shrink to the point where even brim printl curls up after a few minutes. It sits on the plate fine until the nozzle has done a few laps the it starts to curl.

 

I'm not experienced enough to know which way to go in Cura without resorting to glue, tape or hairspray. Other PLA and PLA+ has been printing fine.

 

I've tried nozzle at; 200, 210, 215 and 220 and plate at 60, 65 and 70. I've tried print speeds of 40, 50 and 60ms and slowed acceleration down to 300. I've also tried Low Quality and Standard print modes with resolution down to 0.25

 

With the plate at 70 the printed PLA gets pretty soft yet does seem to adhere better, but still curls. I feel if I could get it to stick it'd probably print okay.

 

The printer (Creality Ender 3 Si Pro) is in a sealed enclosure with ambient temp hovering around 25c / 77f.

 

The Sunlu spec for this printer and this PLA is 220 nozzle and 60 plate, speed 50ms and layer height of 0.26 and that was oddly the worst run tested.

 

Do I reduce initial cooling for the first layer in Cura? Hotter, colder?

I'm at the trial and error stage but don't know enough about Cura to know which way I should be going with settings even if this is something that can be overcome that way. Or likely a setting I don't know anything about.

 

Thank you!

Edited May 30 by Bumbletoon

[Bumbletoon 0]

I think I've solved this. No cooling for the first layer and set the plate  to 90! Anything lower than that and it just doesn't stick. So this may be more of a PSA about Sunlu PLA. I've used their PLA+ Silk and that printed fine at 210 / 60 but these two standard PLAs were ridiculous to get adhesion.

If there's any better way to do it bar glue, tape or spray I'd still love to know how.

Edited May 30 by Bumbletoon

[GregValiant 1,410]

"...for a particular PLA that may just be garbage..." 

That appears to be a big part of this.  Every printer will be at least slightly different, but 220 as a print temperature for PLA is pretty high.  A 90° build plate temperature for PLA is well above the "Glass Temperature" of the material and would normally be considered a "Bad Thing".  It isn't shrinking at that temperature because it isn't hardening.

 

The only roll of filament I ever simply threw away happened a couple of years ago and was an Amazon purchase of Sunlu silky.  It was just really bad and near impossible to print.  A lot of people use Sunlu without any problems so I just chalked it up to a bad roll.

Once burned and twice shy - I've never bought any more Sunlu.

[Bumbletoon 0]

I'm very seriously thinking the same thing. Their PLA seems to need to run VERY hot. At 220 the nozzle starts out fine, but once the print gets more busy and temps start to drop even a little on the hot end (rapid movement, etc.) it jams. I've also removed it from the filament sensor to remove any needless drag and no good. I've got six sunlu rolls in various colours and all do much the same thing. Put a roll of Creality's own PLA in and it prints fine. I definitely wouldn't trust it to run unsupervised with the sunlu PLA

[GregValiant 1,410]

What speed are you trying to print at and what nozzle size?  Pushing plastic through the hot end at high volumes will introduce it's own cooling effect.

[Bumbletoon 0]

That's a good point. Nozzle is 0.4 and speed is 50mm/s. I started at 60, tried 40 and then back to 50. 50 is what the spec sheet recommends for the product and this printer, however it also recommends a build plate temp of 60 and that has no adhesion at all

Edited May 31 by Bumbletoon

[GregValiant 1,410]

Those are very reasonable numbers.  I swapped out the stock Creality flexible bed for the glass one.  When I print PETG (I print a lot of PETG) I use hairspray as an adhesion promoter.  PLA doesn't really need anything and I print it with the bed at 50.  As long as I keep the bed clean it works as it should.

The colorant used in any PLA can have an effect on how it prints.  I've always found white to be tougher and I print it at 200 with the fan at 100%.  I think they use titanium oxide as the colorant so it's actually metal rather than a normal dye/chemical sort of thing.  For comparison I print most PLA at 205 and silky at 215 to try to aid the layer adhesion.

 

You may just have to cut your losses on that filament.  This doesn't really sound like a moisture problem so trying to dry it probably won't make a difference.  You may end up having to use an adhesion promoter so you can at least use it up and move on.

 

[Bumbletoon 0]

I had it in a drying box before use and the ambient humidity is about 20% in the enclosure; I set up a sensor for that and temp.

Some success as I type. Bed at 90, nozzle at 230 and it's on layer 6. I've never managed to get off layer 1 so fingers are firmly crossed. If I can use it to make functional things great, but yes, I certainly wouldn't trust it.

The clog I found out was poor winding. It's VERY tight and largely over one side then the other so jams against the edge of the spool. Just end to end poor quality control and process.

Thank you again for the great thoughts. I'll certainly look at a glass bed as I'm not a fan off the texture on this one. It works great for general, just stick stuff to it, but obviously there's that texture on everything

[GregValiant 1,410]

Ya know, at those temperatures I wonder if it is actually PETG or some other material?

[Bumbletoon 0]

Not according to the sticker on the reel or the listing however you may very well be right. There's no PETG smell though. Now it's stuck on the plate it seems to be building okay; layer 25! Reviews I've just trawled through report poor winding is common, needs to be hotter than normal PLA and the Sunlu spec sheet states 220 for this Ender 3 S1 Pro. I went to 230 and it's flowing okay so far.

Reviews seem to concur that their material used to be okay but in the last 12 months quality has dived.

SUNLU FDM+Filament+printing+parameter+setting+guide.pdf

[Bumbletoon 0]

FOLLOW UP! To be fair to Sunlu, while there's a decent number of quality control issues that seem to be getting reported for late 2023 / 2024 batches, I worked with the other filament I have from them and yellow, red, red clear all printed perfect. Stuck to the plate fine.

The spool stickers say 200 - 220 with a 60 plate

What worked was;

210 nozzle - you may get warping, however any lower and I struggled to get it to stick through a whole, decent size print
50 plate layer 1 and 60 after that
no cooling first two layers, 80 after that
slowed down print to 20ms for the first layer (brim), 50 ms after that

I'm fairly confident I could have printed faster than 50, however I was sick of it failing 🙂

Ender 3 S1 Pro / Cura - in an enclosure with average temp 23c / humidity 26 / dry filament / PEI textured plate

Edited June 8 by Bumbletoon