[Design Prototype Test] likes his Ender 3 printer. There was only one problem. When printing PETG — which is notorious for stringing — the hot end would pick up material and eventually ruin the print. The answer was to mount a cheap Harbor Freight brush somewhere and make the head pass over it after each layer. You can see the video of the design, below.
It sounds as though it worked well and after explaining the concept, he dives into the details of how he designed the fixture and how he mounted it. There’s a lot of good information in there about his particular toolchain and workflow.
We like PETG, and so far we don’t need a nozzle wipe. But it was a lot of work to get retraction and Z hopping set so there wasn’t any drooling. On the other hand wiping down the nozzle makes sense, especially after the preheat when you that hanging filament needs catching right as the print starts, so this seems like a worthwhile upgrade.
Not all printers are the same of course, so you’ll need to modify this arrancement if you don’t own an Ender 3. He mounted his brush on the carriage so it stayed with the head regardless of the Z height. However, if you only needed to wipe on the first layer, you could mount the brush on the bed. In addition, our Anet A8 has plenty of room from the XY home position to mount a brush that isn’t printable so that would be easy to set up automatically.
Despite taking a little work to set up, PETG prints very well. There are lots of other filaments to try and maybe some of them would also benefit. Unfortunately, not all attempts to make this work are successful.