Strange patterns on printed vertical surface
Hi, I was printing something like a standing wall using PETG. After it finished, I noticed that there is a vertical line of patterns. What is it? How do I prevent this from happening again?
RE: Strange patterns on printed vertical surface
The black dot is probably a result of filament getting stuck to the nozzle, burning, and then falling off into the print. Unfortunately, this tends to happen with PETG, which is quite sticky compared to PLA. You can reduce it by making sure to keep the outside of your nozzle clean of residual plastic when you start the print, and avoiding having areas of your print that tend to pop up and bump into the nozzle while printing. Top layer support that doesn't meet perimeters, e.g. for a horizontal or upward-facing blind hole, is where I've had the most trouble with that.
The vertical line might involve some feature on the other side of the wall interacting with how the filament is extruded (in which case, increasing the wall thickness will help). But it looks suspiciously wiggly, so there might also be some over-extrusion happening or some other problem.