You’ve waited hours for your 3D print to finish. Finally, the extruder stops, the print bed lowers, and the moment of truth has arrived. At first glance, the print looks perfect. But wait, what the heck? Are those blobs on the surface of the part?
We’ve all felt that sinking feeling that comes with seeing blobs marring our 3D prints. Small surface imperfections, also called “zits,” are especially annoying when they appear on an otherwise perfect print. These blobs can occur because the extruder frequently starts and stops as it moves around during a print. The blobs represent the location where the extruder started printing a section of the outer shell of your model, then eventually returned to the same spot once it was done printing that perimeter. Joining two sections of plastic without leaving any sort of mark is not easy, but there are ways to help prevent those pesky blobs from appearing on the surface of your print. We cover them in detail in the Print Quality Troubleshooting Guide, but here’s a quick look at what might be causing surface defects.