Wrong Offsets (X/Y/Z) after fusion360 Tool Change

[FerrumD]

Hi

I've designed a small part in fusion360...
there's three operations in one setup.
First two use the same tool... third op uses a 60° Engraver bit... different tool.

I have homed the part (G54) on one corner, as XYZ Zero... and when I run the code it all works exactly as it should... for the FIRST TOOL.
After the two ops with the first tool, the code calls a G53 X0 Y0 and moves the machine to the machine's coord 0 Position for the tool change.
So far so good.
I swap the tool (the machine does NOT have an ATC (yet)...). And tap on Cycle Start to continue...

it actually calls a G54 again - so in theory, it should be back on the originally set working coordinates..
but the second feature is offset badly on X/Y ...


now the interesting part:
IF I output the second op from Fusion as an individual code... suppressing the first two... it works as intended ...


here's the tool-change segment of the G-Code:

Code: Select all

X41.894 Z-5.883
X41.833 Z-5.821
X41.783 Z-5.75
X41.746 Z-5.671
X41.723 Z-5.587
X41.716 Z-5.5
G0 Z15.
M9
G53 G0 Z0.

(Engrave1)
M5
(Move to tool change position)
G53 X0. Y0.
M0 (Pause program for tool change)
T10 M6 (chamfer mill D=6. 6mm Engraver)
S2900 M3
G64
G54
G43 H10
G0 X50.371 Y-16.482
Z15.
Z5.
G1 Z0. F333.3
X50.459 Y-16.192 Z-0.277 F600
X50.545 Y-15.943 Z-0.5

My suspicion is that after the G53, the G54 does somehow not work as I think it should...

thanks for the help...

[lp_felix]

Have you made z zero again after change to T10?

[FerrumD]

Have you made z zero again after change to T10?

no - and would I need to??

When i set up the part i first home the machine,
Then use my 3d manual probe to define G54 X/Y/Z work offset

The g54 and tool offset must be correct, as otherwise the first operation wouldn’t work either

Only when i have a tool change in the g-code from fusion
X/Y are wrong after that

[Delco]

How far out is it ? in XY - maybe loosing steps ?

Why would you go G53 X0 Y0 ????
How are you doing tool change - possible you are moving the steppers while you are doing it ? lots of possibilities without much information being provided ?

[FerrumD]

How far out is it ? in XY - maybe loosing steps ?

Why would you go G53 X0 Y0 ????
How are you doing tool change - possible you are moving the steppers while you are doing it ? lots of possibilities without much information being provided ?

Haven’t measured it, but eyeballing it: about 50mm
Also it seems to be a repeatable error
And happens after the G53
So i don’t think the steppers are losing steps in this case

Is there Anything in the gcode that could throw the G54 out?

[Delco]

How far out is it ? in XY - maybe loosing steps ?

Why would you go G53 X0 Y0 ????
How are you doing tool change - possible you are moving the steppers while you are doing it ? lots of possibilities without much information being provided ?

Haven’t measured it, but eyeballing it: about 50mm
Also it seems to be a repeatable error
And happens after the G53
So i don’t think the steppers are losing steps in this case

Is there Anything in the gcode that could throw the G54 out?

Nothing in your Gcode shown that would do it.

[FerrumD]

How far out is it ? in XY - maybe loosing steps ?

Why would you go G53 X0 Y0 ????
How are you doing tool change - possible you are moving the steppers while you are doing it ? lots of possibilities without much information being provided ?

Haven’t measured it, but eyeballing it: about 50mm
Also it seems to be a repeatable error
And happens after the G53
So i don’t think the steppers are losing steps in this case

Is there Anything in the gcode that could throw the G54 out?

Nothing in your Gcode shown that would do it.

Ah. Well then i shall be hunting that ghost in the machine for a bit

[ger21]

Delete the line with the G53 in it, and see if it's still out.

[FerrumD]

Delete the line with the G53 in it, and see if it's still out.

I'll give that a try today... maybe replace it with a G28 and see what happens..

[FerrumD]

ok for those who're interested in the solution / culprit of the issue:

MASSIVE lost steps..

I found that (alignment issues, now fixed) the X-Axis was over-torquing the pathetic stepper (open loop) for it to loose a LOT of steps.
essentially it got stuck... it would move well and home well, but sometimes a rapid move would "jam" it up enough- this is why this happened sometimes during tool changes...

Solution: proper alignment and tossing the steppers out of the door. the alignment issues were introduced (by me) after a modification I had made ,...
But the sad and silly open loop steppers remained an issue and would loose steps every now and then whilst milling too... so I've treated myself to a set of clearpath SDSK servos... should be at my place by the end of the week.


But it wasn't a software issue...