Z axis questions


(Simon Wilke) #1

Reposting this since it got closed without a response.

I’m planning on implementing a motorized Z table into my k40, with a z probe. Now, I understand that pressing the focus z button will just execute the gcode command so that my smoothie firmware on my laserboard homes the z axis to the probe.

If I then enter a material thickness, and set it to “line cut mode”, will it change the z offset to be in the middle of my material?

And if I am doing a job that involves both a scan and a line, will it change the z offset back to the top of the material for the scan, and in the middle of the material for a line? Ensuring that the focus point is correct at all times.


(Oz) #2

It will not - The top of the material will be used for everything. If you want it to focus at the center of the material you would need to specify a Z offset for the cut (line) layer to push the Z down.


(Simon Wilke) #3

What does the material thickness setting do?

And also, another question, I am running smoothieware, and for my z probe/z upper endstop, I plan to have it attached exactly 10mm above the focal point. How do I tell the firmware to retract 10mm after it has hit the endstop and set that as the zero for the Z axis?


(Oz) #4

Material thickness sets the base Z height for your jobs, if you have Z enabled and do not have “relative z moves only” enabled.

The focus question would be something for the Smoothieware devs - I don’t know that one.


(Ray Kholodovsky) #5

It’s just a homing offset.

Change these guys around. Where is your Z endstop hooked up, which port? And are you able to explain which way Z moves when you tell it to jog up and down?

gamma_min 0
gamma_max 200


(Simon Wilke) #6

I have both a Z-min and a Z-max, it is the Z-min that I want to offset, and its hooked up to the sig and gnd on the Z-min contact. And I don’t really understand that second sentence but Z moves up when I tell it to move up and moves down when I tell it to move down.


(Simon Wilke) #7

For Oz

So if I have the bed top as the focus point when its correctly homed, and set the material thickness, it will move the z bed so that focus is ontop of the material?

And i’m guessing that after i’ve done that I set the z-offset per layer, depending on if I want to cut or engrave


(Ray Kholodovsky) #8

Which switch does Z home to? Default is Min. Is the Min switch located at the top or bottom of the Z table’s path of travel?


(Simon Wilke) #9

Z homes to min, and its located on top.


(Ray Kholodovsky) #10

Ok, so we want to modify the gamma_min value.

Right now, when you home the Z, it goes to the top and that is considered 0. So you should set that to either 10 or -10. One of those will do what you want. I think, in theory it should be -10, but you might have things flipped from how I imagine it should be.