PETG loses bed adhesion in the front of the sheet after 50-60% of the print on large area prints
Hello,
I've got my Prusa Core One roughly one month ago and after assembly I got pretty good results on the spot using PLA (BASF Ultrafuse, Polymaker).
Since I wanted to print some more robust prints I bought a textured pei sheet to print PETG from Prusa and tried to print several larger objects, always slightly adjusting the parameters. Currently I'm using the following setting:
Nozzle: 250°C
Bed: 90°C (first layer) - 85°C rest (or vice versa, I'm not sure at the moment)
I have no problem printing smaller area objects in PETG, either with Polymaker PETG or Prusament, but as soon as the overall area gets larger then the parts of the magnetic top cover ( https://www.printables.com/model/1226383-prusa-core-one-magnetic-top-cover-with-integrated, all printed in Prusa Jet Black PETG), after roughly half - 2/3 of the print the object looses adhesion in the front of the sheet.
I tried cleaning the sheet thoroughly with soap and water, but to no avail.
large area prints i tested so far:
https://www.printables.com/model/152592-honeycomb-storage-wall (the bambu one, the largest possible on the core one)
https://www.printables.com/model/1187356-magnetic-print-sheet-holder-prusa-core-one
https://www.printables.com/model/28337-scraper-for-build-plate-version-2
All of them lifted exclusively on the front of the sheet, not in the back, and overall seemed to stick rather well to the sheet, except losing adhesion after the mentioned print duration.
I'd be grateful if anyone can suggest what I should try next.
The standard first advice for larger prints that warp off the print sheet is to use a brim; I would try a 5mm brim first.
Cheerio,
RE: PETG loses bed adhesion in the front of the sheet after 50-60% of the print on large area prints
Will try, thank you!
RE: PETG loses bed adhesion in the front of the sheet after 50-60% of the print on large area prints
Tried your suggestion, unfortunatley it didn't work. It was a lot better, but with 5mm brim and even 10mm brim it still lost adhesion. I'll try to grab the gcode file from the usb stick tomorrow, maybe theres some other option that is off and leads to my print failing.
my preferred size of the honeycomb wall unfortunatley doesn't leave enough space for a brim, so I guess i will need to switch to a smaller version, unless there is a way to only apply inner brim on the outer cells of the honeycomb wall.
RE: PETG loses bed adhesion in the front of the sheet after 50-60% of the print on large area prints
What kind of textured PEI sheet did you buy? Is it a Prusa brand or something else? You can either try this: BIQU CryoGrip Pro Glacier Build Plate or this Satin Powder-coated Print Sheet both work very well with PETG. I never have adhesion problems even on large prints.
unless there is a way to only apply inner brim on the outer cells of the honeycomb wall.
Of course. It is always possible to design custom adhesion helpers and supports, the slicer's algorithms are good but generic.
The next step to try are 'Mickey Mouse ears' - look them up; Prusa, probably for copyright reasons, calls them helper disks.
Right click on the model then: Add part > Gallery > helper_disk.stl
They are one layer thick cylinders, move them, you will need several, to the places where the warp stresses are strongest and you need to assist adhesion.
- and if you need to customise more you can design your own one or two layer thick shapes and either add them to the original design or if they are likely to be used more than once, upload them to your gallery.
Cheerio,