Unexpected vertical tool offset following the change of workspace G54 G55 G56

[Anonymous]

Hi,

I wish to do a job requiring 2 tools in 3 Work Coordinates System (WCS) : G54, G55 and G56.
Tool 1 must work in each WCS before changing to Tool 2.

I use the option "Multiple WCS Offsets / Order by Tool" of the Setup in Fusion 360.

I observe that the tool change induces a vertical offset of tool 2.
This offset is precisely the difference between length compensations of tool 1 and tool 2.
This difference is even doubled in the last WCS G56 at the end of the program.

e.g.
Tool 1 Length Compensation -130,00
Tool 2 Length Compensation -133.50
Compensation difference = 3,50

DRO Work_offsets at the end of the program:
G54   X0.00   Y 0.00   Z0.00
G55   X0.00   Y15.00   Z3.50
G56   X0.00   Y30.00   Z7.00
(The 3 Work_offsets are Y-aligned and spaced 15.00).

I'm using Fusion 360 / Mach3 Version R3.043.062 / PostProcess Mach3mill_43262

Here attached a very simple Fusion project /  Gcode to help fixing this issue.

I would be grateful for if you could support me for this problem.

[johnswetz1982]

What is it you are expecting to see. From what you describe I would expect that to be the behavior. Tool 1 is -130 (I assume mm) from the spindle nose. Tool 2 is -133.5 from the spindle nose.

What ever tool you used to set the WCS system will be the tool length - distance to Z0.0 for that WCS. What you didn't list is the WCS register values. So you would have something like,

G54 -400.0,

G55 -396.5,

G56 -393.0 

[Anonymous]

Hi johnswetz1982,

I thank you for your 1st analysis.

here is a photo report to better visualize what is wrong.

How could be explained this z offset ?

[timo_gross]

Hello,

just an idea.

When system changes between G54 and G55 and so on do you need to call G43 (tool offset) again?

Did you check z-value for all G54, G55 and G56 same?

My post processor is repeating the G43 every coordinate change.

Greetings Timo