Marlin Motion Related Configuration.h Settings for MakerFarm i3v

[printbus]

I'm finally finding time to experiment with different motion settings (feedrates, acceleration, etc.) for my i3v-8 (8-inch i3v). It'd be great to find that magic sweet spot of settings that prints reasonably fast while still providing fairly decent print quality. In experimenting with settings, I'm getting everything from inconsistent results to results that are suspect to be dependent on filament temp/liquidity, print weight on the bed, etc.

Anyone care to share how they've adjusted the Marlin motion settings from the MakerFarm defaults? What was the rationale/benefit of the changes, and how extensively do you believe the changes were a good thing?

Examples of motion related settings include:
HOMING_FEEDRATE {X,Y,Z,E}
DEFAULT_MAX_FEEDRATE {X,Y,Z,E}
DEFAULT_MAX_ACCELERATION {X,Y,Z,E}
DEFAULT_ACCELERATION
DEFAULT_RETRACT_ACCELERATION
DEFAULT_XYJERK
DEFAULT_ZJERK
DEFAULT_EJERK

DEFAULT_AXIS_STEPS_PER_UNIT {X,Y,Z,E} is another motion setting but X,Y, Z are fixed by the hardware design and E is something we all typically calibrate

For completeness, we should probably include MANUAL_FEEDRATE{X,Y,Z,E} from configuration_adv.h, but I don't know that there is much to discuss with it. The stated intent is that these are the feed rates used during axis moves requested from the LCD panel. The way the code seems to work, however, it seems more accurate to say that you can use MANUAL_FEEDRATE to set manual move speeds that are slower than those in DEFAULT_MAX_FEEDRATE. DEFAULT_MAX_FEEDRATE will still "over rule" any attempt in MANUAL_FEEDRATE to go faster for moves requested from the LCD. So, set MANUAL_FEEDRATE to whatever lower speeds you want once you have your DEFAULT_MAX_FEEDRATE values figured out.

FOLLOWUP COMMENT: It would be just as useful for people to describe attempts at settings that didn't pan out.

FOLLOWUP COMMENT #2: The thread morphed into my attempt at better understanding each of the settings and putting together gcode snippets that could be used to demonstrate or test different values. This in turn has led to insight beyond the Marlin motion settings - stepper motor drive adjustment, limits on certain slicer settings, extruder E-steps calibration, etc. I've often added "homework" that is intended to encourage readers to walk through the math on their own, or to look at the specifics of their unique situation. I have tried to not make any of this up on my own; links to key references I found are included for those who want to rethink my interpretations of them.

FOLLOWUP COMMENT #3: The thread focuses on Marlin parameters as they were named in firmware circa late 2014. Labels may vary with newer versions of Marlin. Tests were performed on an i3v with OEM-like M5 threaded rods on the z-axis and belt pulleys on x and y. Extruder tests were performed with a Greg's Wade extruder and hexagon hot end. The concepts discussed here have a generic applicability, as would the gcode snippets provided for various demonstrations and tests. Only specific results on settings would expect to change for different printer models or extruder configurations.

TABLE OF CONTENTS LINKS TO THE REST OF THE THREAD:
INCREASING THE Z HOMING FEEDRATE
GENERAL INFORMATION ABOUT THE MOTION SETTINGS
ACHIEVABLE STEP RATES AND MOTOR ROTATION RATES
ARRIVING AT VALUES FOR DEFAULT AXIS STEPS PER UNIT
THEROETICALLY ACHIEVABLE FEED RATE VALUES
CAN 42BHH48-050-24A TYPE MOTORS BE DRIVEN FASTER?
A STAB AT CALCULATING A MAXIMUM PRINT SPEED
TESTING XY TRAVEL MOVEMENTS WITH GCODE
TESTING Z AXIS TRAVEL WITH GCODE
TESTING EXTRUDER MOTOR DRIVE WITH GCODE
UNDERSTANDING THE JERK SETTINGS
UNDERSTANDING LINEAR ACCELERATION
MARLIN MOVE PLANNING
LINEAR CONCENTRIC SQUARES TEST
PRINTBUS SETTINGS RECAP
ESTIMATING A FEED RATE LIMIT ON EXTRUDER E-STEPS CALIBRATION
RIPPLE INVESTIGATION - PART ONE
RIPPLE INVESTIGATION - PART TWO