According to one of Tom's videos, there are three elements to the speed of the printer:
- the acceleration. This is said to often be the dominant factor, as it controls how long the printer takes to get up to speed. The Folger config sets this to 1000. Many Prusas uses 3000 or even 9000. I raised it to 3000 in configuration.h, and didn't see any difference.
- the jerk speed. This tells the printer the maximum instantaneous change in speed it can make before the acceleration parameter has to be considered. I didn't change it.
- the regular printing speeds. configuration.h has these set to a maximum of 250 mm/s, but the Slic3r configuration sets them a lot lower than this. So these are the values I changed.
My test object is something which is roughly a long thin rectangle about 100mm by 10mm, and I printed it with the long direction along both the X and Y axes. Before making any adjustments, Slic3r estimates it as needing 20 minutes 27 seconds to print. The part of the Slic3r settings to change is Speed, under Print Settings. Folger's values are: perimeter and small perimeter speed 40, infill 50, solid and top solid infill 45, omitting the value I didn't change. I now have them as: perimeter and small perimeter 110, infill 120, solid and top infill 105. The resulting estimated time is 15 minutes 14 second, that is about 75% of the original. In the print about half of layers involve long travel (non-printing) moves without much printing, so it might be even better on other objects.