Preventing bed going down

[mbun]

Is there a way to prevent the bed going down when homing in certain situations ?
I did a print the other day that took up almost all of the Trident's height so when I homed the printer after that the bed ground down on the bottom.
Is it an idea to incorporate an end-stop at the bottom ?

 

[shiftingtech]

Not an easy one: klipper doesn't offer any method of utilising endstops at both ends of an axis.

In theory, I could imagine placing an endstop down there, configured as a gcode button, then writing a homing_override that decides whether or not to hop based on the state of the button. But it's pretty theoretical, I'm not aware of anybody having anything like that out there, ready to use.

 

[mbun]

I wouldn't know how to do that.
So I'll just have to take care not to switch the printer off after it finishes so I can raise the bed before homing .

 

[lord-carlos]

Separating nozzle from bed for homing is just there to make sure there is no contact between them, right?
And a trident bed does not sag like the 2.4 gantry?

In that case, could you maybe minimize the amount the bed goes down? Just enough to separate nozzle from bed in case you home with nozzle touching bed.

 

[mbun]

could you maybe minimize the amount the bed goes down?

I could if I knew where I to adjust this option ?

 

[Dave32]

Separating nozzle from bed for homing is just there to make sure there is no contact between them, right?
And a trident bed does not sag like the 2.4 gantry?
In that case, could you maybe minimize the amount the bed goes down? Just enough to separate nozzle from bed in case you home with nozzle touching bed.

You can't really do that safely, since it still has to accommodate any potential tilt.

Remember that the X/Y/Z homing is performed prior to the Z_TILT_ADJUST, so the bed has to be lowered enough for the nozzle to clear the back right corner of the bed when it homes X then Y. If you adjusted the Klipper config to only lift the nozzle slightly, then it would only take a small twist of the front left screw to pitch the back right bed corner upward and cause a nozzle collision.

 

[lord-carlos]

I could if I knew where I to adjust this option ?

safe z home I assume. https://www.klipper3d.org/Config_Reference.html#safe_z_home
The z hop.

I don't own a trident, thus I don't know how often and how much the bed tilts. So be careful to not set it too low.

 

[mbun]

I don't think so. I once tried changing the z hop but what happens is after homing it goes down to the new z hop and then up again to the old value.

 

[lord-carlos]

I don't think so. I once tried changing the z hop but what happens is after homing it goes down to the new z hop and then up again to the old value.

Maybe you have a probe that overrides it?

 

[mbun]

I use the Voron TAP, so Z is commented out in the printer.cfg