To fix warping in infill 3D models, use a heated bed set to your filament’s recommended temperature to minimize thermal contraction from uneven cooling.
Warping often happens when infill layers cool faster than outer layers, so reduce cooling fan speed for the first few layers or add a brim/raft to improve bed adhesion. Dry hygroscopic filaments (like PLA or PETG) to eliminate moisture that causes expansion and warping.
If issues continue, try increasing infill density slightly (e.g., 15% to 20%) for more structural support, or re-level the bed to ensure even first-layer contact.