[az_356]

As the title says. When I have a small diameter item on the 4th Axis Rotary I turn the Feedrate up to 60-75.0IN/min to get a reasonable speed on the cut time. Unfortunetly, this also changes the X feed to 60-75.0IN/min and if there is a straight cut across the X it's just too fast. Eventually I lose steps on my machine and the part is ruined. Is there any way to speed up the A axis but not the X?

Thanks in advance.

[SirDenisNayland]

Your rotary axis should be feeding at a rate relative to a working diameter no? 65ipm at what diameter?

If you really have to compensate in this way, then you're going to have to for the x lines as well. As far as I thought a rotary axis works off of a degrees/min feedrate.. at least on a lathe/turning center, say I have a line with my C axis, and X axis, it moves to both positions at a feedrste relative to the c axis in deg/min, the x axis is linked and moves relative. If on the next line I have just an x move, its going to move in ipm, and its going to move really fast as 65ipm is a lot faster than 65 degrees a min, unless your work radius is over 100 inches hah.

Forgive me for my not so solid response, I've never had the pleasure of working with a 4th or 5th axis mill yet, so only know 4axis from a lathe perspective, which is about the same thing anyway..

Edit: since this is in a cam forum id assume you've got a setting somewhere, that well, needs setting.

[John S.]

Depends on the controller.
There should be some setting to make the controller aware of the diameter of the work and that will link the two axis together.

In mach3 it's on the settings page.

John S.

[az_356]

For the CAM milling module you get to set the feedrate for X,Y and A(rotary axis) as one setting and Z as a separate. The part is 0.75" in diameter so to get reasonable speed I need the A to be fast but X slower. If it's an arc where you move the X and A together everything is OK, but a straight line on the X is way too fast. I needed to run a part last night so I set it at 18.0IN/Min, took 5 hours for a simple part. The controller is Mach and I have enetered the diameter in there as well. Thanks again for the input.