Quote Originally Posted by CoffeeCup View Post
...Looking at Printbus's Repetier/Cura settings I see retraction distance set at 1.5 mm and minimum travel before retract at 4 mm. Were these proven sufficient?
IMO they're a reasonable starting point, and you can adjust from there as you learn more and go down the usual path that we all do of trying to optimize the heck out of everything.

Again, I wouldn't assume these are cast-in-concrete, works-for-all-in-every-case settings. Anything that can affect the extrusion flow can make a difference. Filament characteristics, nozzle temp, layer thickness, first layer gap accuracy, nozzle size, extent of print cooling airflow, how well the extruder has been calibrated, and how well the retraction acceleration and speed have been adjusted come to mind. On top of that, print designs vary in where they REQUIRE a travel move, which can affect how often a retraction might be applied. Then things like infill and gap fill settings in the slicer can affect where travel moves are used for touchup work; that alone can be a significant variable in how many retractions might be applied.

Retractions can help improve print quality, but each pass of the same section of filament over the hobbed bolt increases the risk of the hobbed bolt carving away at the filament to the extent that extrusion stops.

Sure, it can be frustrating to figure all this out. We've all been there. Well, maybe except for those that have closed printers that don't provide a lot of options on settings. I was initially flabbergasted in how configuring a slicer can require dealing with dozens and dozens of settings, but now I wouldn't have it any other way.