I suspect this is your entire problem, because it happened to me too.
40+ 3D Printer Bed Plate PNG. It's probably made from aluminum and, even when new, is slightly bowed toward the center or edges. So, if you are not ready to pay extra bucks for a heated bed and add.
TAZ 3D printer Reprap bed plate mount 300 x 300mm for DIY ... from ae01.alicdn.com
Buy 220x22x0.5mm 3d printer heated bed tape online at the best price. This step will depend on if you are printing on the aluminum plate or if you have added a glass plate to your printer. I used #6x1/2 wood screws to attach the plates to the plywood.
Voron v0 3d printer heated bed kit 110/220v 100w pei sheet 6mm aluminum plate.
Sigma3d printer, now here ! It can be placed directly on your printer bed or on a metal flex plate like our ezflex² system. Leaves no residue on the build plate when removed. Spareparts for a specific 3d printer brand can be found here
