How to Achieve Smooth Motion for Rotational Axes? G64?

I have a machine with XYZ and C axes. When I use G64 for motion along axes like XYZ only, similar to the following code:

G01 F3000
G64
G01 X0 Y0 Z0
G01 X0.1 Y0.1 Z0.1
G01 X0.2 Y0.2 Z0.2
...
G01 X69.9 Y69.9 Z69.9
G01 X70 Y70 Z70


The machine moves at a speed of 3000, which is what I want

However, when I add a rotational axis like C, similar to the following code:



...
G01 X0 Y0 Z0 C0
G01 X0.1 Y0.1 Z0.1 C0.1
...
G01 X69.9 Y69.9 Z69.9 C69.9
G01 X70 Y70 Z70 C70


The machine moves very slowly. It seems that G64 only affects the XYZ axes? I conducted another test where only the C axis moved, similar to the following code:

...
G01 C0
G01 C0.1
...
G01 C69.9
G01 C70

Again, the movement was very slow.

How can I solve this problem? I want to achieve smooth motion when the linear axes XYZ and the rotational axis C move simultaneously.

8 years old video, but should be still relevant:

Thank you for your reply. I carefully watched the video you sent.
The issue discussed in the video is one that I may encounter later, and it was very helpful.
However, I think I may be describing a different issue. I forgot to mention a detail when I was asking my question just now. It's actually this issue that I'm more eager to solve.

When using different step values, the degree of deceleration of the rotary axis varies. The smaller the step value, the lower the speed. However, this issue does not occur with the linear axis when using G64.

For the linear axis, regardless of whether the incremental step is 1, 0.1, or 0.01, the velocity can reach 3000 when using G64.

With the rotary axis, when the step value is 1, the vel is 2800.
When the step value is 0.1, the vel is 866.
When the step value is 0.01, the vel is 262.

For example:
G64 P0.01
G01 F3000
;Linear axis step 1
G01 X0 Y0 Z0
G01 X1 Y1 Z1
...
G01 X70 Y70 Z70; vel: 3000

;Linear axis step 0.1
G01 X0.1 Y0.1 Z0.1
G01 X0.1 Y0.1 Z0.1
...
G01 X69.9 Y69.9 Z69.9
G01 X70 Y70 Z70; vel: 3000

;Linear axis step 0.01
G01 X0.01 Y0.01 Z0.01
G01 X0.01 Y0.01 Z0.01
...
G01 X69.99 Y69.99 Z69.99
G01 X70 Y70 Z70; vel: 3000


;rotational axis step 1
G01 C0
G01 C1
...
G01 C69
G01 C70; vel: 2800

;rotational axis step 0.1
G01 C0
G01 C0.1
...
G01 C69.9
G01 C70; vel: 866

;rotational axis step 0.01
G01 C0
G01 C0.01
...
G01 C69.99
G01 C70; vel: 262

G01 C0.01

Thank you again for your reply!

That is likely because LinuxCNC falls back to one-line lookahead for moves involving any other axis than XYZ. This means that velocity is no longer blended over multiple path segments. The motion planner sets the speed as to be able to stop the movement at the end of the next segment which means that the shorter the segment the slower the speed.
This is an internal limitation of the current motion planner, as a workaround for multi axis gcode generated by CAM it is usually recommended to output longer segments.

Thank you for your reply.

linuxcnc.org/docs/2.9/html/user/user-con...gramming-the-planner

I have read the following document, Naive CAM Detector section.
"Naive CAM Detector
Successive G1 moves that involve only the XYZ axes that deviate less than Q- from a straight line are merged into a single straight line."

As you said, CAM seems to only work on XYZ? Is there any other solution? except 'output longer segments'.