Heatbed problem?
Hi,
I have tried to print a big model in PETG. But the print comes loose from the build plate in the two front corners and the result is a warped print. I have tried all the usual tricks, brim, warmer heatbed and glue. I have cleaned the build plate both with dishwashing liquid/water and IPA.
I use the Prusa PETG filament and "CORE One Textured Powder-coated Print Sheet". Bought the Core one printer fully assebled in September last year.
I measured the temperature with a cheap IR thermometer, the absoulte value can't be trusted but it shows that the temperature in the corners where the print comes loose is more that 10 degrees lower than on the rest of the build plate. Is this my problem and is my head bed defect?
RE:
Are you letting the heat soak complete before starting the print? Also, make sure the nozzle is clean. Debris on the nozzle can throw off the bed leveling mesh.
Also, try to use mouse ears on the corner. Adding an adhesive like Magigoo will also help.
RE: Heatbed problem?
May we examine the 3MF file in the slicer in order to formulate specific assistance?
Mods for Core One: Core One HT 450 degrees, Comfortable display , Very fast print start and Reducing noises
Mods for Prusa XL: Very fast print start
RE: Heatbed problem?
Here is the model (zipped): model
I started with using the pre-heater before I started the print. The nozzle is clean. I have tested with glue.
RE: Heatbed problem?
The 3MF is not complete, but you can see it as long as the file shows what you see.
PETG is easy to print, that's true. But if the speed is too high and the cooling conditions are still unfavorable, large objects will simply deform.On a straight section at high speed, the extruded filament has “more” time to cool down. In the corners, the filament is additionally cooled down quickly by the fan due to the reduced speed (blue).
Try printing the infill, perimeter, and outer perimeter more slowly. They can be at different speeds, but currently it is simply TOO FAST.
Mods for Core One: Core One HT 450 degrees, Comfortable display , Very fast print start and Reducing noises
Mods for Prusa XL: Very fast print start
RE: Heatbed problem?
Try a smooth plate. It has much better adhesion than the textured, but don't forget to use adhesive/release agent or you may ruin the PEI sheet when removing the model. I prefer 3Dlac, but Magigoo or hairspray based products will do too ( anything but that messy glue stick that Prusa recommends for obscure reasons ).
RE: Heatbed problem?
Another thing you can try is increasing the number of perimeters to 3 or 4 and switching to 10 or 15% Gyroid infill. Can also try decreasing the infill anchor. The extra walls will give additional stiffness and the gyroid infill won't pull so hard on the walls.
RE: Heatbed problem?
It is strange that you doesn't see the complete model. I just downloaded the zip-file and opened the model in the PrusaSlicer. I got it all!
I tested to lower the speeds you suggested by 30% but it didn't made any difference.
How much should/cloud the temperature differ on the surface of the hotbed?
RE: Heatbed problem?
I have done some more testing. I draw a solid bar and printed it with standard settings for 0.20mm layer, structural. Prusa PETG as before. First I printed it in the middle of the build plate and that worked great. Then I moved the print to the fron of the build plate. Disaster! 
RE: Heatbed problem?
Now I have done one more test. I printed the piece in the front of the build plate, now with the temperature rised to 95 degrees. And now it printed without any problem. This tells me that it is a heatbed problem an not a leveling problem. And yes, I poked on it before I took the picture...
Is there any way to verify that the heatbed is okay. Can I verify it in some way? Measure the resistance?