Linear Advance for Prusa i3 MK2

thingiverse

This is for the firmware update that enables Linear Advance. Link for download: http://www.prusamk2.com/linear-advance-prusa-mk2/ Summary: Source: Marlin Under default conditions, extruder axis movement is treated in the same way as the XYZ linear axes. The extruder motor moves in linear proportion to all the other motors, maintaining exactly the same acceleration profile and start/stop points. But an extruder isn’t a linear system, so this approach leads, most obviously, to extra material being extruded at the end of each linear movement. Take the common test-cube as an example. Even with the best tuning the corners are usually not sharp, but bleed out. The top solid infill displays roughness where the print direction changes on perimeters. These problems are minor or even imperceptible at low printing speeds, but they become more noticeable and problematic as print speeds increase. Tuning the flow can help, but this may lead to under-extrusion when starting new lines. Some slicers include an option to end extrusion early in each move, but this adds more complexity to the G-code and has to be re-tuned for different temperatures and materials. Since the root cause is pressure, LIN_ADVANCE de-couples extrusion from the other axes to produce the correct pressure inside the nozzle, adapting to the printing speed. Once Linear Advance is properly tuned, bleeding edges and rough solid infill should be nearly eliminated. Again... Link for download: http://www.prusamk2.com/linear-advance-prusa-mk2/