[dcrace]

Hoping someone can shed some light on my brain-melting confusion of 5 axis programming...

Machine is a Mazak VC-500. B axis table rotates about Y and C is Z.

We run these parts in another 5 axis (Doosan, A is along X axis) using G68.2 coordinate rotation. I did not write the original program, so I am still trying to understand how the G68.2 is defined.. Due to some tight true position tolerance, we also probe each part when loaded on the fixture for X/Y pos. and rotational error in the C axis. Part is programmed from the common origin regardless of rotary position.

Original code:

A-90.C90.
G68.2X0Y0Z0I90.J-90.K0 (A pos. is 90, why I90.?, C is 90 / why J-90. and not K90.?)

G53.1
X0Y-.7
G43Z1.6265H06M8

When we bought the machine, we were told to program using G54.2 dynamic work offset and also sold the G54.4 WSEC option ($900.00) and we wouldn't need to use G68.2?

The apps guy took our original Doosan program and modified it calling up G54.2 after positioning the rotary:

G90G54G00G69
B-90.C90.
G54.2 P1 X0.7000 Y-0.0000 Z10.
Z1.6265 M08

Once he came in and assisted in getting this running, he changed the program to use a DIFFERENT style of G68.2 programming because he said it had to be that way because we probe the parts??G0B-90.C90.
S2838M03

B-90.C90.
G68.2 P3 Q1 X0 Y0 Z0 I0. J0. K1.
G68.2 P3 Q2 I0. J-1. K0
G53.1
X0.7000 Y-0.0000 Z10.

Z1.6265 M08

Once again, confusing me as the explanations I have found are confusing.

Fusion outputs the G68.2 different also:

G0 B-90. C90.
G68.2 X0. Y0. Z0. I0. J90. K90. (shouldn't "J90" be "J-90."?)
G53.1 P1

if anyone can explain, it would be appreciated as I haven't yet found a complete description of the tilted workplane or if the part can be programmed using G54.2/G54.4 using the probing cycles. I have also seen talk about a macro to probe the part, calculate the difference from COR and populate the G54.2 or G54.4 but haven't seen a complete or proven example for the Mazak.



Thanks in advance.

If the simple way is to position the rotary, Call up G54.2 and program off the origin of the part, then that seems like the most logical solution

[lucaswalker]

Hi,

IJK in the G68.2 are probably euler angle definition to rotate reference (with the +-90 inputs),
The one with +-1 inputs looks likes an axis selection followed by some reverse, but its not very clear...

You can rotate the reference in any convenient way, there is no "unique" way of doing so, whats important is that the set of coordinates thats comes after are coherent with what you have chosen as a new reference.

G43 probing result in Z axis compensation (in 3 axis programming), maybe because of controller limitation you have to keep your Z axis invariant after reference rotation (in 5 axis).