# Talk:Prusa Mendel Assembly

The "Firmware Modifications" section at the end contained only three calculated z_steps_per_mm results without mathematical explanation. Not terribly helpful, especially without values for X, Y, and E! Paragraph renamed to "Firmware Calibration", and added exact equations for all four stepper drivers. I've had perfect success with this E_steps_per_mm calculation, which was derived from these sources:

http://www.brokentoaster.com/blog/?p=358 and http://hydraraptor.blogspot.com/2011/03/spot-on-flow-rate.html

nophead discusses packing density in his extruder calculations, but this term can currently be assumed as 1.0 in firmware and instead controlled from within Skeinforge 40+. --Threedonuts 23:31, 5 September 2011 (UTC)