larger object warping, need advice to avoid it
Hi
I need some advice, I am printing spare parts for the mk3 and been having great success with the smaller parts however I have warping on the LCD screen holder. I am using real filament PETG transparent blue, using slic3r latest version to slice the models (using Prusa generic PETG settings). only thing I have changed is the extruder temp and heat bed temp, I have used the suggested settings for the filament 240 for the extruder and 55 for the bed.
I tried using glue stick when I first attempted using the PETG as I had read a lot of horror stories about PETG sticking to the bed too well and damaging the PEI sheet, but I didn't have any luck getting the PETG to stick well with it. so I tried just printed straight on to the bed and have great success every time with first layer adhesion and no damage to the PEI sheet. I clean the bed with window cleaner. as I said I have no problem with smaller objects but larger object warps how can I reduce the chances of it happening. The LCD screen got to about 70% done and one side started to lift of the bed. there's no drafts in room I print in so I can eliminate that. i have thought about increasing the bed temp. i also thought about increasing the extruder temp but don't want to risk damaging the pei sheet and not sure if that would really help as i am already getting good first layer and layer adhesion with the recommended temp. i have also not raised my first layer height after getting it set with the PLA, but i had read in the forums that people have had to do this as the PETG sticks too well at that height. i am confused as some advice on the forum seems contradictory to what i am experiencing with my printer, it seems the longer the print time the more likely hood i have of warping. i have attached some photos of prints with the PETG. Any help appreciated
Re: larger object warping, need advice to avoid it
I clean with IPA between ALL prints, then i apply some Windex to get PETG to get off easier.
My bed is at 80C for PETG.
Its hard to see but maybe your Live-Z could be a little more negative (more -).
Try upper the bed temp first.
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Gert
Re: larger object warping, need advice to avoid it
Transparent filaments sonetimes print happily at lower temperatures
That might help
Adding a brim will also help
Regards Joan
I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK
Re: larger object warping, need advice to avoid it
Hi
thanks for advice I will try upping bed temp and see how that goes, I may try lowering the z height a small bit, but I have it pretty much dialled in for perfect first layers I can always change it back if it doesn't help any or makes it stick too well.
@ Joan I had thought about adding a brim but I thought the LCD holder had a large enough surface area on the bed area that it should not need one, could it be because the walls are thicker at the ends and the thinner parts are cooling down quicker than the thicker parts making it pull on the ends. I will try a brim as well.
for anyone else reading this post window cleaner is definitely the best thing for getting the PETG to stick to the bed on first layer and for releasing it once print is done. I have managed to print 90% of the mk3 parts so far with no issue this is my first issue with using PETG so happy days :D. I thought it would be lot harder to get good prints from it.
Re: larger object warping, need advice to avoid it
I was having a similar issue with a large square tray that I was printing. It failed multiple times. I finally added a 10mm brim and applied painters tape to all four corners to ensure the thing stayed down. I haven't had to do this with every part but with the big square stuff it has been an issue for me with the pei sheet.
Re: larger object warping, need advice to avoid it
Hi sean
thanks for the tips.