Air cutting above stock

I’m still somewhat new, but have a fairly good understanding. I have been frustrated by the fact that no matter how I set the program, the CNC still thinks the stock is twice the height. I use the touchplate to zero everything, the simulation in Fusion runs fine, but the spindle starts aircutting .75 in ABOVE the board. I’m at my wits end with this thing and have no idea why nothing is working. I have no doubt it is something simple, but I cannot find it. please help

Is it an 0.75" board? Perhaps your machine and your design disagree on where “z=0” is? I.e. if your design has the Z=0 origin on the bottom of the board, but you use the touch plate on the top of the board, you’ll be off by the width of the board.

I’ve found that keeping some cheap 1-2-3 blocks around is handy - you can “G0 Z3” and use the 123 block to see how close to 3" you really are.

Can you post a picture of your Fusion 360 setup in the manufacture space? Or even better post your F3D file?

I completely agree, if the program has Z0 on the bottom (spoil board surface) and you touch off at the top of your project, it will air carve. If the programmed thickness of the touchplate is less than the actual touchplate thickness, it will also air carve.

Okay, ive tried everything i can think of and things continue to get worse. I managed a 2d contour program by programming the z to .75 in below the stock in Fusion360. Moving on to the next project, everytime i tried to flatten the spoilboard, it would shut down with y axis soft limit exceeded. Fought with that for 2 days and gave up. Next, tried a simple 2d contour and again air cutting. Then, when the program finished, the machine would lock up and not move.
I feel I am the proud owner of a 13,000 dollar lump of junk at this point!

Okay, ive tried everything i can think of and things continue to get worse. I managed a 2d contour program by programming the z to .75 in below the stock in Fusion360. Moving on to the next project, everytime i tried to flatten the spoilboard, it would shut down with y axis soft limit exceeded. Fought with that for 2 days and gave up. Next, tried a simple 2d contour and again air cutting. Then, when the program finished, the machine would lock up and not move.
I feel I am the proud owner of a 13,000 dollar lump of junk at this point!

It would be really helpful if you could post your F3D file here, I could take a look at your setup. I suspect it’s a simple, but not obvious setup error.