TIL that that 200% is not relative to the extrusion width on other layers. I finally read the hovertext and discovered that it is percent of first layer height — so when I tried to make it 100% I made a real mistake. A 0.8mm nozzle doesn’t do a good job of printing a 0.3mm wide by 0.3mm tall line. So I went to 0.4mm thick first layer and 200% first layer extrusion width setting for 0.8mm first layer extrusion width, and it looks much better. Going to 0.6mm for all layers looked better yet.
Next, I tuned linear advance.
Now, the frames I’m printing are structurally sound; they bend well without delaminating. But I’m still getting significant stringing. I tried printing a temperature tower, and the entire range I tested, from 245⁰ to 285⁰, I kept seeing stringing. But that doesn’t test printing at speed, and with the 0.8mm nozzle that’s where a lot of the challenge lies. The tower, which since it was all small moves was only slow movements, looked better around 255⁰, but when I tried to print the visor with the hotend at 255⁰ the plastic didn’t get hot enough to stick to the 75⁰ bed even at 60% of 60mm/s (36mm/s) so that didn’t help.
Other than some stringing, the visors are looking good and printing quickly with the 0.8mm nozzles, and I was having to clean them up anyway before, so I think I’ll stick with the 280⁰ first layer and 290⁰ other layers, with 60mm/s speeds and 0.6mm layer thickness for all layers, and just clean the strings off afterward.
So going from 85mm/s with 0.4mm nozzle to 60mm/s with 0.8mm nozzle, but twice the extrusion width and twice the layer height, works out to a speed win, even though I still have to clean strings off the edges.