Quote Originally Posted by printbus View Post
SUGGESTED HOMEWORK AND INDEPENDENT RESEARCH

While we wait for the conjuring of miracle answers...

Consider playing around with the Z axis details in the Prusa leadscrew calculator. Note how using a metric pitch threaded rod to obtain metric linear movement typically always involves an integer number of steps. Switch to using Imperial threads in the calculator and see about all you can do is get close. Imagine now the pain those with Imperial rods have in using nice, even metric layer heights. After playing with the calculator, you'll likely never buy a printer with Imperial threaded rods.

What might happen to the DEFAULT_STEPS_PER_UNIT for the Z axis if the Z rods were replaced with M8?

Increasing the difficulty now since at least the Prusa calculator doesn't have a pull-down for it, how would the DEFAULT_STEPS_PER_UNIT change if the Z rods were replaced with 8MM ACME leadscrews that have a 2.5mm pitch?

The value of 4000 steps per mm for the Z axis in DEFAULT_STEPS_PER_UNIT seems to be a large number of steps. Using higher pitch M8 or 8MM ACME leadscrews would reduce the number of steps required to obtain the same linear movement. Ignoring any other limitations like available motor torque, reducing the number of steps required per mm movement would also increase the achievable feed rate. What kind of achievable feed rate on the Z axis might be possible with the M8 or 8MM ACME used instead?

Now repeat as much of this as required to assess what would happen to the Z axis achievable feed rate if you reduced the microstepping on the Z-axis motor to something other than 1/16. Can you come up with a reasonable combination of threaded rod pitch and microstepping that might allow the Z motors to move faster, thereby reducing the Z axis time in homing, and also reducing the time spent in fixed-point layer shifts? Do you know enough about stepping motors and microstepping to explain why that would be a stupid thing to try?
if your ok with some more noise you can remove a jumper from Z and speed it up 2X by switching to 2000 steps per mm or 1/8th micro i have done this to the printer we have at school it has a massive .8 nozzle and uses 3mm abs all day so i switched a few things i changed the pulleys to 16 tooth and dropped x and y to 1/8 micro i can't tell at all in the prints But for the speed boost it has net me it was worth my time. i was at the limits at what that POS can do right around 140mm/s infill before it start skipping now i print all day with infill at 210mm/s bridges at 60mm/s rest at 100mm/s first layer at 40mm/s using hair spray