1

**General Mach Discussion / Inverse time feed bug?**

« **on:**January 05, 2009, 03:41:55 PM »

I am using Mach3 to control 4 axes (3 axis mill with rotary table), and can't get G93 inverse time mode to work properly. Here's some g-code that does not work as expected:

The problem is the G1 move, which is specified to take 0.06 seconds but actually takes many seconds to complete a motion of 1.4 degrees in A and .00003" in Y). When the insignificant Y axis motion is removed, Mach 3 performs the G1 in a small fraction of a second as expected.

Can someone confirm that this is a bug? If it is, how do I report it.

What about a work around? My best bet may be to go back to G94 (units per time feed mode) generating synthetic feedrates using the square root of the sum of the squares of the axis movements (inches for X, Y and Z, and degrees for A) divided by the desired time for the operation.

If it helps, I think may have updated my installation to the latest version of Mach 3, but I'm not certain. The "about" screen just says R3.00.

Code: [Select]

`G93`

G0 X0 Y0 Z0.4 A-0.7

G1 F1000 Y0.00003 A0.7

The problem is the G1 move, which is specified to take 0.06 seconds but actually takes many seconds to complete a motion of 1.4 degrees in A and .00003" in Y). When the insignificant Y axis motion is removed, Mach 3 performs the G1 in a small fraction of a second as expected.

Can someone confirm that this is a bug? If it is, how do I report it.

What about a work around? My best bet may be to go back to G94 (units per time feed mode) generating synthetic feedrates using the square root of the sum of the squares of the axis movements (inches for X, Y and Z, and degrees for A) divided by the desired time for the operation.

If it helps, I think may have updated my installation to the latest version of Mach 3, but I'm not certain. The "about" screen just says R3.00.