i3 Mega Z-Homing/config

[brave swan]

Hey there! I’m currently working through installing Klipper on my Anycubic i3 Mega S, and just had one question I couldn’t seem to find the answer for online. In most config flies , it says “Home position is determined by 3DTouch. Z limit switches are not used.” In regards to this, would it become an issue if the Z-Gantry became unlevel, as the dual Z-Switches won’t be able to correct for this. Would this be a problem, how could it be fixed? Any help/advice would be much appreciated! I’ll add a slightly overexaggerated illustration as well..

[topaz ginkgo]

Ahoi @brave swan!
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[remote snow]

I never seen a i3 Mega config and the printer. first question would be does it support 2 independend z stepper or is the same driver used.

Such specific printer questions should would be much better suited on a discord that is specific for that printer

[brave swan]

Firstly, thank you so much for answering, I really appreciate it. It does have two independent z stepper’s, both of the side also have a limit switch, which the base firmware uses to home, and make it level. If it helps, this is the config I was looking at: https://github.com/widapro/3d-printers/blob/master/anycubic-i3-mega-s/klipper/printer.cfg.

I’ll see if I can also find some more printer specific servers to provide additional help.

[remote snow]

if you have 2 limiting switches you can use it for homing but you than have 2 offsets to consider each time.

the endstop offset of your z stepper is used to define the 0 z orgin

if you have a probe e.g for bed leveling than there is also an offset

if I look at the config folder of klipper I see https://github.com/Klipper3d/klipper/blob/master/config/printer-anycubic-i3-mega-2017.cfg that uses both endstops

In the end it is your printer and your decison. Personally I would use the 2 endstops to insure your gantry is parallel to your bed. And than deal with the probe offset in your bed mesh

[brave swan]

Alright, and I assume I could just implement the BLTouch config into that? Thank you so much for your help.

[remote snow]

sure than can be done always

[brave swan]

Alright! Once again, thank you so much!

[remote snow]

so use your example and simple do the following

step_pin = ar46
dir_pin = ar48
enable_pin = !ar62
step_distance = .0025
endstop_pin = ^!ar18
position_endstop = 0.0

[stepper_z1]
step_pin = ar36
dir_pin = ar34
endstop_pin = ^!ar43
enable_pin = !ar30
step_distance = .0025```

remove [safe_z_home] home_xy_position = 100,100 speed = 150 z_hop = 5 z_hop_speed = 10

and modify ## bltouch mesh bed leveling [bed_mesh] speed = 200 horizontal_move_z = 5 mesh_min = 23,28 mesh_max = 190,190 probe_count = 4,4 fade_start = 1.0 fade_end = 10.0 algorithm = bicubic by adding
zero_reference_position: 105,105 that should also be the point where you make your endstop and probe calibration test

See https://www.klipper3d.org/Config_Reference.html#bed_mesh

that would calculate out your probe to endstop offset difference

But as said I never seen the printer in real world and did not use an cartesian style printer for a long time