If the top of your print resembles a block of cheese with holes and bumps on the surface, then that means that it didn’t cool properly or it wasn’t thick enough.
You can prevent this from happening by adjusting the fan in order to cool your print sufficiently after printing. If your fans are in the right place, then the problem may be caused by not having enough top layer thickness.
- Inspect the fan’s position and settings: Insufficient cooling is the number one cause of pillowing so make sure that your print is getting the proper airflow. You can also adjust the fan speed in the G-Code to prevent the upper layers from falling through the voids of the support structure.
- Amp up the top layer thickness: You can adjust this in the Bottom/Top Thickness setting in your 3D printing application. Standard thickness is usually 6 layers of material and 8 if you have a smaller nozzle and filament. Start with 0.6 mm and increase by 0.2mm if the problem still persists.
- Avoid this filament size: It has been reported that 1.75 mm filaments are more likely to cause pillowing.