Large Print Not Sticking (Curling) on corners
In trying to print this larger piece that I created (A Dominion Card Holder), having an issue where the corners of the print are not staying flat on the bed during the print. I thought that maybe it was too much surface area, so added the hexagon cut outs, just to reduce surface area. In reading other posts, have done Z bed leveling, cleaning the bed with alcohol, raising the bed temp during first level, increasing the fill % to 50-60, so there would be enough weight to hold it down.
I even printed with a raft, and the raft stayed stuck to the bed, but still had this same effect on the printed piece, where it bowed out on the sides. I have also printed a bottom part for this holder (not pictured) and have the same issues. It's a ton of filament to use each time I print, so getting tired of trying new things and wasting hours and filament on the test.
Would appreciate any thoughts or suggestions. 
Are you printing in a draft? If the cooing is uneven then the part cools unevenly causing warping.
Reduce air movement and possibly increase bed temperature.
Cheerio,
RE: Large Print Not Sticking (Curling) on corners
Not sure I know what you mean by printing in a draft. Can you explain more?
I have increased the bed temp to 70 on first layer. Attached are images of my settings for that and the cooling fan. 
RE: Large Print Not Sticking (Curling) on corners
It's common for large box-shaped/rectangular objects to warp. Assuming Live Z is well calibrated and the steel sheet is clean (using hot water and fragrant-free dish washing soap), here are a few approaches that have worked for me:
- Slow down print speed.
- Add Mickey Mouse ears to the corners. Theres a "helper disk" in Prusaslicer's Add Part library but I prefer to use a cylindrical part, maybe 10mm diameter, change height to single layer height, then place the part at the corner. Repeat for each corner.
- Add a brim around the model, 5 mm or more. Wider or 2 -layer high brims may be needed but may not work with the size of the model or may require being added in your CAD software.
- Use Layerneer Bed Weld ( https://www.amazon.com/Printer-Adhesive-Layerneer-Original-Filament/dp/B079984GV5/ ). You only need a thin layer.
- If you have design control over your part and it's possible considering the intended use, you can try to round the edges and/or add holes to the base of the model.
- Combination of above. Usually, brim/ears does the job, or some Layerneer if needed, but large, rectangular objects can be a challenge.
Formerly known on this forum as @fuchsr -- until all hell broke loose with the forum software...
RE: Large Print Not Sticking (Curling) on corners
What type of filament are you using?
ABS (and ASA to a lesser degree) shrinks during cooling and is notorious for warping and pulling up from the build plate on large thin flat pieces.
I've even had one large flat piece crack on cooling when I used a very liberal dose of Layerneer to prevent it from pulling up in the corners. (This was not on a Prusa, but on an Ultimaker.)
PLA/PETg will usually give nice flat smooth prints.
Dabs of Layerneer where the corners will hit will usually prevent it from separating from the build plate.
