Help with PETG in Slic3R  

Re: Help with PETG in Slic3R

I use three different brands of PETG, and I use the profile of Prusa PETG for all of these.
Prusa basic settings, but adjusts perimeters and sometimes infill. The result is perfectly in my eyes.

Re: Help with PETG in Slic3R

Beware Prusa defaults is all I can advise. The Prusa defaults work out of the box only with Prusa filament, you may get acceptable results but don't count on it. Every manufacturer requires specific settings 's, you should set your own PETG profile up for ALL settings for Print, Filament and Printing specific to the filament manufacturer and start at the manufacturers recommended values - if the manufacturer doesn't specify any then don't buy their filament any more.

PETG does not like to be rushed, Prusa's defaults are way too fast for PETG in my opinion, but PETG doesn't like to dwell too long either or you can get issues with 'ooze'.

You need to be very sure of your Z height too - if this isn't well sorted then PETG can be a pig. It needs a slightly higher nozzle than PLA. How much higher is a bit of trial and error I'm afraid. Do yourself some single layer test prints of 30 to 55mm square at different points on the bed - see how the infill looks, needs to be nice and flat, not rough to the touch and should blend nicely with the perimeters, write on them so you know where they came from on the bed so that you can compare when you do the next run. This involves a lot of playing, change one setting at a time then you know what is affecting things - do this any other way and you may get a good result but you won't know which change led to it. I'd advise doing a single test square at a time, get it as close as possible then try the same settings somewhere else on the bed. I tend to do this around the bed mesh levelling points (9 of them).

Until you get the printer properly dialed in don't even think about layers less than 0.15, PETG is more sensitive to heat than many think and needs a bit of extra space to get out of the nozzle - 0.05 or so higher I find- but this depends on the manufacturer. Watch the cooling, smaller parts need it more, some prints the fan is a liability and causes layer to layer adhesion issues.

Re: Help with PETG in Slic3R

Thanks. I will try to dial in with a good first layer print. I thought I had it dialed in, but I could be wrong

Re: Help with PETG in Slic3R

Here you can find a collection of popular custom profiles which continues to be updated regularly. Personally I have had zero luck with them. Prusa profiles have proven the best for me. I've only printed PLA, and just one single PET print for a variation of the R3 fan shroud, nevertheless it was a perfect print just as all my PLA ones are, using Prusa profiles, and any attempt to deviate from those (other than little things like infill and such) results in worse prints.

https://github.com/eoprede/prusa_profiles

Re: Help with PETG in Slic3R

Here you can find a collection of popular custom profiles which continues to be updated regularly. Personally I have had zero luck with them. Prusa profiles have proven the best for me. I've only printed PLA, and just one single PET print for a variation of the R3 fan shroud, nevertheless it was a perfect print just as all my PLA ones are, using Prusa profiles, and any attempt to deviate from those (other than little things like infill and such) results in worse prints.

https://github.com/eoprede/prusa_profiles

Thanks. I will give them a try.

Re: Help with PETG in Slic3R

PETG is more sensitive to heat than many think and needs a bit of extra space to get out of the nozzle - 0.05 or so higher I find- but this depends on the manufacturer. Watch the cooling, smaller parts need it more, some prints the fan is a liability and causes layer to layer adhesion issues.

I have almost no PET printing experience, but via deduction what you state does make logical sense. One thought that did occur to me is how (I assume) the common 'natureworks' based PLA (is there even another kind in use?) might exhibit more commonality across brands, but might PETG vary from brand to brand more? I see lots of small players moving lots of PLA/ABS/PC but often they don't even offer PET. 30CAD for 1 KG, double the price of PLA, of eSun (I assume comparable high standards as Prusa) PET, and my second all time PET print going now using Prusa defaults and no problems.

Thanks for the note about how object size and cooling could demand more refined settings. This is valuable info ahead of time, so it is more easy to know what to look for. Cheers!

Re: Help with PETG in Slic3R

for matterhacker PETG it took a while for me to get something dialed in to say i can work with it. here is the basics of what i adjusted from default prusa pet after buying 11lb of that....er....junk (their packaging leaves ALOT to be desired, 11 lb of it came to me pre moistened and while its still slowly drying, gets better daily)
keep that filament dry. i mean really dry, im not comfortable with using an oven to dehydrate, so i made a few descant containers and have them fed out of a drybox im still working on, made ALL the difference

extrude temp to ~245c
build plate to ~70c
do a perfect first layer calibration. but thats true for all material, petg even more. a good calibration and i have no issues with sticking.
use a brim for anything smaller than an inch. you want the first layer build area to be at least 2 inches(50mm). for every 5mm up, you want at least 2mm out. if its already a big flat thing, dont worry too much (maybe like a 3mm brim to avoid any unlikely warping, if its a lego figure for example, make it the full brim 50mm out
fan off until layer 2 or 3, then up to 50%max (pre r3 update due to better airflow with new parts, it may need to be set lower)
retraction to ~3mm on move (this made most off the difference in stringing)
non print move speed upped about 50% to reduce stringing.
infill is based on the print, and ive been doing fine with 25%, and even very nice vase mode for my descant containers.

i will attempt to get these settings refined more in this post asap , but yes, i agree, its a pain to find settings for all different materials, im thinking of a big spreadsheet of all available filaments, their ideal settings per printer/nozzle( may focus on prusa only for starters), it may be a pain to get it organized but its a vital thing noone has really made yet. i mean i use meltink PLA and ABS, and that stuff using default prusa$$$ settings is mindblowingly good. but is their pla-pha just as good. and at what settings. we all want to know.
if there is already a list, i would love to see it an contribute.

Re: Help with PETG in Slic3R

I found a brim and trusting the Prusa rather than manufacturers settings fixed most issues.
Did also find that some PETGs are MUCH easier to print than others.

Re: Help with PETG in Slic3R

Thanks. I have found the same.

Re: Help with PETG in Slic3R

i cant say i found it easier, in fact i was about to make a drive and toss that 10lb MH roll through a window for the first week.
it seems a bit easier to stress break (not flex) than any PLA i have used (may be my pre soaked rolls). (hydrolysis)
stringing is much worse with PETG, but nothing that ~3-5mm retraction couldnt help, the stringing is almost super thin now but happens , it just happens. invest in a low power heat wand/gun (i use a butane torch with heat blowing cap) if you decide to do PETG on a regular basis.
correct, some filaments just like some printers more. i absolutely LOVE meltink PLA, and my R3 meltink ABS parts appear flawless (first time using ABS and prusa's gcode file), and very consistent by using prusa's default filament settings. i will be testing their pla/pha once i get lower on the matterslacker rolls
will i continue to use PETG? yes. just a completely different brand.
PS, i print with octoprint by default, i have put in a ending Gcode command that pulls a little bit of filament back at end of prints. it seems to ooze after prints and starts blobbing before the next print.