Need help to install 5 axis knematics

Hello everyone.
back to the forum,actually I had a lot of difficulties concerning the 5 TCP setting (type: xyzac-trt) on my machine. It works well but to tell you the truth, nothing is clear to me regarding the Z axis offset values.

which theoretical value should I enter in:

setp xyzac-trt-kins.z-rot-point ...            for 180mm Z-axis travel
and how much for: setp xyzac-trt-kins.z-offset ...        with an  A axis offset of 44.6 mm.

the values ​​I entered work (I adapted them by testing the settings) but I found no logical calculation.(setp xyzac-trt-kins.z-rot-point -127 (mm)???
and (setp xyzac-trt-kins.z-rot-point -44.6  (ok) mm

Do you have a theoretical explanation?

Thanks for your help .

Sorry i made z mistake about "step xyza c-trt-kins.z-rot-point -44.6 " it's setp xyzac-trt-kins.z-offset -44.6 ( in fac it's a raduis of A axe)

To make my zero "Z" I first make a G41h1, then I come tangent to the middle of my axis Pivot AC. and I enter the value "step xyzac-trt-kins.z-rot-point ..." in relation to the machine origin (taking into account the offset of tools). This part is not well documented on the linuxcnc documentation, many people are trying to understand how it works.

Thank you

Hello,
I found the simple but necessary calculation concerning the value of "setp xyzac-trt-kins.z-rot-point ..." .

Here is my procedure : with an axis A of 44.6mm radius
 and tool N°1 of 50 mm length .

- Mount the tool in the spindle (50 mm overhang)
- add this tool and this length in the tool table
- activate the G43h1 (tool length compensation "code G")
- Come tangent to the center of the AC axis (be careful that the A axis is horizontal "A0")
-Read on LinuxCNC the offset in Z ( ex : -222 mm from the origin )

- calculation : 50 ( tool length ) + 44.6 ( A axis pivot point ) - 222 = -127.4 mm

setp xyzac-trt-kins.z-rot-point -127.4

Maybe there are other calculations but on my xyzac-trt machine it works very well.

Sincerely
 

Hi all,

I am using 2.8.4 linuxcnc which works fine, but now I want to implement 5 axis switchkins.
Is there a way to do it in v2.8.4 without switching to v2.9 as I think 2.8.4 works best for me.

Regards
Abhishek