Auto setup

furynick

A big challenge would be to have an auto-setup mechanism.

I spent many hours/days to find best values for X/Y feed rate and jerk. I think it could be possible to add a feature that compute the max movement speed at least for 3 axis, I guess it's not possible for extrusion feed rate.

Perhaps I'm wrong but this test could looks like that :

Max Speed (repeat for each axis)
homing
move with slow acceleration from home with a certain feed rate
move back to home with previous speed
if endstop hit before returned to 0 max speed is previous feed rate tried
increase feed rate and restart test until error

Max acceleration (repeat for each axis)
homing
move with a certain acceleration from home with max feed rate
move back to home with previous acceleration
if endstop hit before returned to 0 max acceleration is previous tried value
increase acceleration and restart test until error

Max jerk
homing both X & Y
make a significant move (2cm on X, 90° arc - not a G2 one - with certain radius)
move back to home
if endstop hit before returned to 0 max jerk is previous tried value
increase jerk and restart test until error

Repetier

Nice idea, but that does only work partially.

In real world prints you will not use these limits. If you print you get other resistances, e.g. a small resistance when going over the model. If you are at limit this will cause lost steps.

Also jerk and acceleration are more determined by print quality and how much shaking you want then real possible limits. I know my printers can go much faster and harder then I use to while printing, simply because I want a quiet print that does not shake too muck as shaking decreases print quality.

So yes, you can determine limits that way, but you do not want to use them.

furynick

Of course you'll not use the printer at its limits but getting such limits can drastically help on finding the right setup.

Since you know the "hard" limit, you can more easily adjust all parameters to get better prints.

furynick

Perhaps you can just add an "M" command to check home error.
For ex. M260 measure distance to endstop and print difference with current known pos. This also can help measure backlash.
G28 X0
G1 X100 F2400
M260 X0
returns X:-0.032 according to ENDSTOP_X_BACK_ON_HOME

With this info I can write a little soft that sends commands to printer and find hard limits by detecting when missed steps occurs.

Thanks for your help.

RepetierSupport

Nice idea, will see if I get the time.