Gaps and Holes in Top Surfaces

The top of a finished print should normally form a continuous surface. If you can see gaps or infill beneath the top layers, there may not be enough solid material to bridge over the infill. Increase the number or thickness of top solid layers in your slicer. The appropriate value depends on layer height. Using only two top layers at a 0.2 mm layer height creates just 0.4 mm of solid material, which is often insufficient. Increasing infill density can also help because the top surface has shorter gaps to bridge. Check for under-extrusion. If individual lines appear too thin or do not touch each other, increasing top layers alone may hide rather than solve the underlying problem. Slowing the top surface speed can improve appearance. Some slicers include ironing, which passes the nozzle across the final surface to improve smoothness. Common causes: insufficient top layers, low infill density, under-extrusion, excessive top-surface speed.