First Layer Not Sticking (Poor Adhesion)

Lower the nozzle closer to the bed. The lines should be slightly squished, not round. Clean the build plate with Isopropyl Alcohol (IPA) or warm soapy water to remove finger oils. Increase the bed temperature by 5-10°C. For PLA, use 50-60°C. For PETG, use 70-80°C.

Increase retraction distance. For Bowden extruders, try 4-7mm. For Direct Drive, try 0.5-2mm. Lower the hotend temperature by 5°C increments. If the plastic is too hot, it becomes too liquid and oozes. Dry your filament. Materials like PETG and Nylon absorb moisture rapidly and will string excessively if wet.

Perform a cold pull (atomic pull) or replace the nozzle. Slow down the print speed. The hotend might not be able to melt the plastic fast enough. Check the extruder tension arm. Ensure the gear teeth are clean and gripping the filament actively.

Warping (Corners Curling Up)

Ensure room temperature is stable. Avoid drafts. Use an enclosure for materials like ABS and ASA. Use a brim or raft in your slicer. Apply glue stick, hairspray, or special 3D printing adhesive to the bed.