Safe retract Height

I have a .75" wasteboard on yop of the stock waste board, Then my stock is 2"thk
Im doing some air cutting to check for clearances.
At the start of the operation the z moves up and maxes out even though it does not need to goto max height.
When complete the tool extracts but the height it retracts to is slightly below the 2" stock which would cause a plow through to go to home.
is there a way to move the same height up a bit.
It seems like the retract height in fusion does not affect this final move to home

Sounds like a post processor issue. If you lost steps at the start, your Z “thinks” it’s higher than it is. That last Z lift will be lower than expected because of this (all cuts will be deeper).

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I did a test where it did not max out on the initial move. the tool retracts to a safe height then drops back below the stock as it travels back to the home position.

Can you share your gcode? At least the first 20 and last 10 lines.

It seems to be working now
Is there a setting in cm to set a default safe height

Yes, but it needs to be done on each toolpath. it carries over from one to another if you set it when you create the first one, then create another. If you already have them, you can edit them together (sometimes), or one at a time to change the retract and safe heights.

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What changed? If it just worked one time after not working, you’re probably losing steps in your Z.

I’ve also got 3/4” of wasteboard on top of my stock wasteboard. I cut a 2 1/4” project and found the same issue (crash Z on retract, machine loses it’s zero and plows too deep). Retract height is critical, just enough to clear with a small margin. What finally worked for me in addition to retract height was to raise the router in the mount by an inch or so. If you raise it 3/4” you’ve pretty much made up for the added wasteboard thickness.



In CC, the safe retract height is in mm while the other sizes are imperial. I was caught once when I thought it was in inches. The bit traveled on the board instead of lifting clear.

I have had the same problem but because as stated above the Z axis was retracting all the way, slipping and getting out of sync with the zero set. I am using flat clamps now and had set the retract height too high to avoid hitting the clamps during rapids. Now I use the default retract height and have had no further issues with Z getting out of sync. Live and learn.

if i manually lift the z axis and release it it will drop, is that too loose?

My XXL does the same thing. It is normal as far as I can tell. During power on the stepper motors hold the carriage. So if you lift it up all the way manually with the power off it will probably drop some. The springs are at their most tension when the Z axis hits the switch. So if you are not having problems when running you should be ok. If you have a dust extraction hose make sure it is supported. I bought some 2.5" hose from Amazon that is extremely flexible. I made a sort of diving board above the XXL and made sure the hose is long enough to go to the extreme corners. The diving board is centered on the spoil board. I put a wire tie on the Z motor bracket with enough slack so when full down there is enough hose to not bind the Z axis.

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