XZC Lathe Rotational feed rate - Kinematics?

Andy,
You were dead on. Thank you!
The inverse time fixed my rotational timing issues.

Whoo hoo!

-Tom

i face same issue (2.5.3)
and solved with inverse time feed g93
but i also try to say my angular axis (C-Axis)= linear

but with g94 same issue i face

in my fanuc 11m hmc with b axis i never face this type of issue
now i am planning to identify what exact problem is .....e

checked in 2,6.8 issue is same

In inuxcnc right now, inverse time is the only easy solution.
For linuxcnc to adjust the c axis feedrate it would need to know the distance of the tool from the center of the c axis.
In a lathe this is easy as it will always be X radius, but most other machines it can be in an arbitrary position.
There is currently no way to tell the motion controller this info.
Linuxcnc's motion controller is very generalized, it does not change based on what type of machine it controls.

Is your fanuc 11m a machine that the b axis center can always be assumed?
If yes, then I would think the manufacturer changed the motion controller to reflect this.

Chris M

Is your fanuc 11m a machine that the b axis center can always be assumed?

i think fanuc calculate roatry axis center to machine's spindle face (in case of hmc machine) and according to this position they calculate b axis feed which is related to x,y,z axis feed

otherwise when we make some rotary cam on my fanuc 11 m hmc we never face issue with feedrate of b axis with other axis

same program and same cam when we manufacturer on linuxcnc system we face this issue

but still i am looking to find out what exact solution is .

Dear andypugh
i attach my machine construction
i successfully make nx 10 post with G93 feed in each line with feedrate according to my component

but when five axis operation start and on my globoidal cam i found issue on surface ...
actual surface is wavy (up down slopes are there) specially when b c x y z axis move together

i set min error,backlash,feed,everything is ok

and i am using pivote distance and tool length from my cad cam software
so machine with linuxcnc no need to calculate tool length and pivote

dimension are ok but surface is only issue when i cut with 6 mm ball mill it show around 0.5 mm steps on surface of cam

now i am confuse what to next

if you can suggest me something i can try

thanks

kalpesh patel

Thanks for suggestions
I tried g61 and g64 p0.010
But I found same result
But I try again

And I want to know that if I write g64 p0.01 means my axis move in 0.01 tolerance correct?

You wrote slow accelerate z axis is problem

But I set all axis with same acceleration
I also try to set different acceleration on different axis as per load but results are same

I am using pivote distance of my machine in nx software and linuxcnc only need to follow as per program generated by linuxcnc tool length also I enter in nx software

Is there any possibility that if pivote calculation is calculate by linuxcnc is better then nx software calculation ?

I am using pivote calculation with nx software because linuxcnc does not support accel during five axis move if I use tool length calculation and pivote distance with linuxcnc it create very zerky movement

If you can write something more on this topic I can try your suggestion to find out solution

Thanks for reading and suggestions on my topic

Thanks
Kalpesh patel