[74BurkeMVN]

Hi guys,
I'm a relative noob to the CNC world, but I've had my 1100 for a year now. Lately I've been making a couple 4th axis parts in quantity. I have the 8 inch superspacer. I program everything in Fusion360.
What or where is the rotational speed of the A axis set? In the G-code I see the F numbers on A moves are in the thousands, but relative to the programmed tool feed, the A rotation seems to be very conservative. IE - I'm running a 3/8 corncob in 2024 taking it easy at 40IPM, but the tool never gets there in an adaptive strategy because most of the movement is in A.

Thanks,
-TJ

[daniellyall]

A axis speeds are set in the machine you have them way more than the linear axis you will need to see what is set in the machine and go from there.

[kstrauss]

If I understand your question correctly the answer is complicated!

See the section titled "Feed Rate" which is near the end of Section 7.1 of the Tormach Pathpilot documentation and also the description of G93. Operation is different in Mach3.

In the simple case of moving only the A-axis, the F word value specifies the rotation rate in degrees/minute. If moving only X,Y,Z then the F word specifies the rate in inches or mm per minute. If doing coordinated 4-axis moves then things become a little un-intuitive and you probably want to use inverse time mode specified by G93.

[109jb]

Not sure about Pathpilot, but LinuxCNC which is at Pathpilot's core does it this way:

if any of the linear axes are moving at the same time as the rotary axis, the move will perform essentially like a linear move, ignoring the rotational axis for calculating the rate at which to move but with the rotary following so as to end at the same moment that the linear axes stop..

For example G91G1X100F100A360 would result in a move that takes one minute to complete and in that time, X will move 100 units and A will make one 360 degree revolution.

If only the rotary axis is programmed then the feedrate will be applied to the rotary axis.

[74BurkeMVN]

Thanks for the replies so far. It does indeed seem complicated. From what I have observed while my parts are running, the A-axis moves much faster when the tool is ramping down into the stock than it does when doing a 2d adaptive move. I'll look into the G93 move documentation...