I have yet to purchase perfectly straight linear rod and I think - just like we have automatic bed leveling - we could have automatic X and Y compensation. All one would need is a straight edge reference -metal ruler or thin wire - and metal probe (nozzle?). Stretch a wire/ruler along X or Y axis and use script that moves along the axis and looks for contact of probe with the ruler/wire. For example, when calibrating 200mm X axis:
move probe to X=0 then towards ruller/wire, once contacted record Y position,
move Y+10
move X+20
move Y until wire/ruller contacted - record Y position
move Y+10
move X+20
move Y until wire/ruller contacted - record Y position
all results outside of the line between (0, contact point) and (200, contact point) would be a compensation value applied to X axis.
Another way would be to draw a grid with a pen/marker attached to hotend, take a picture of it then have a program process the picture to calculate a compensation grid that would be uploaded to printer's firmware.
EDIT: this feature would be even more useful with carbon fiber rods that cannot be straightened
Edited 1 time(s). Last edit at 09/13/2017 09:30PM by newbob.