Mach 3 Speed Issue on four axis foam cutting setup!!

[Domdonder]

Hi All, My machine ignores the Feed command on the y and a axis when they are locked using the formulas tab to enable me to do 2 axis cutting on my 4 axis setup. I had some kind help from learned friends and they found that it doesn,t matter what is linked to a the problem occurs. It seems like the a axis throws the speed out and mach compensates automatically to reduce the difference. They found a workable solution by re assigning the axis on the a side, unfortunately this is not workable in my instance, can anybody help us please it is an older version of Mach and I prefer using it for its build in cam software that I know and understand!!
Kind regards

[ger21]

Is the A axis set to linear, or rotary?

[Domdonder]

Hi Gerry

Machine is set up with X and Y axis on the left side and Z and A axis on the right side
A is set as linear.

Motor tuning for each axis was checked and all 4 axis were identical.

With no formula’s and no slave axis,
The following was noted:

G1 X100 f200 X axis moved as expected at the correct speeds
G1 Y100 f200 Y axis moved as expected at the correct speeds
G1 Z100 f200 Z axis moved as expected at the correct speeds
G1 A100 f200 A axis moved as expected at the correct speeds
G1 X100 Y100 f200 both axis moved as expected at the correct speeds

As soon as the A axis was run at the same time as any other axis (be it by Gcode or by formula or by slave axis )it seemed as if the movement of the two together ignored all accel and speeds
If A and B are paired all works perfectly.