Holy %*#!ing @!^). I don't care how fast your PETG says it is, you should not be printing PETG this fast. With other materials (I don't have any high speed PETG, but I have high speed TPU) I find the "high speed" version prints better at the same speed as the regular version. For PETG, that's 50-60mm/s, tops.
*Turns on acceleration control to see what the defaults are*
*faints*
And I'm sorry, but this one is bugging me:
You couldn't get a rounder model? I've made a table with more faces than that... and it was supposed to be square. Also the seam between those two parts is so obvious, you can actually see it in the preview:
Also the seam at the rim:
Cue the preview:
That is going to look... sub-optimal.
Okay, back to the speeds: Slower. Much. As I said, 50-60mm/s tops, I don't care what the filament says it can do. And turn on acceleration control and lower that to like 1000mm/s², tops. I'd go 500 myself, but I'm overly cautious. Don't forget to lower the travel acceleration while you're at it. PETG is a much stringier material than PLA: if you're going too fast, it's inclined to hold onto the nozzle and be pulled along by it before it has time to dry. My printer (Ender-3 V3 SE) has a top acceleration of 2500mm/s² and I've seen it pull PLA with it as it zooms off, warping that whole section of the print, let alone PETG (and you don't wanna know what it's like with TPU).
I'm thinking that's what's happening here: you're not getting strings, you're getting bits of filament which are supposed to be part of the model being taken for a ride because they don't have time to dry.
A couple of other things, though these can be personal preference or depend on the filament:
- I print PETG at about 245°. You may (or may not) get better results by increasing the temperature. Especially at the speed you have it set to, you'd need it hotter just so it gets hot enough as it zooms through the hot end at a ridiculous flow rate. But even at a lower speed... I still print a little hotter than you. You could print a temp tower to test it.
- Is 25mm/s the fastest you can retract? That would help explain the need for coasting.
-
You're using a lot of filament printing skin where it's angled like this:
I'd change Top/Bottom > Bottom Layers and Initial Bottom Layers, lower the former and maybe set the latter a bit higher. The initial bottom layers are what's touching the plate. - I don't envy your job getting that support interface off.
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gr5 2,224
I can't really comment on settings unless you post the project file. Also a photo of your print showing the strings would help. Please post your project file - do menu "file" "save project" and then post that here.
Also you should know that PETG needs to be kept dry or it will string quite a bit. Wet PETG prints 10X better than wet nylon filament but PETG if left out in normal air will absorb water after a few days and then be "stringy".
If your printer has a heated bed, unwind enough for the next print, put that on the heated bed, put the spool on top of that (in other words no need to cut the filament). Set the bed temp to below the softening temp. So 55C should be safe. Cover all that in a blanket/towel or box. Let it sit for 2-8 hours like that. Then print again and you should see a big improvement in stringing.
Store your PETG in a 2 gallon (6-8 liter) bag with 1 cup or 1/4 liter of color-changing desiccant. I recharge the desiccant when it starts changing colors or about once per month.
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newdeal99 2
Here is the project file, sorry I didn't take photos of the strings and I brushed them all away so now it's just a poor surface and I reprinted it using the purse slicer. The roll was brand new and the same roll prints fine with the purse slicer file which seems to use basically the same settings. I attached the project file and like I said there are no travels inside the part but yet a ton of strings. I tried printing outside to inside and inside to outside and both were poor. I tried grid infill and line infill and both were poor also.
Cura outer flare.3mf
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