An air pass, also known as a dry run, is a crucial step before cutting your project on a CNC router. It allows you to simulate the cutting process without actually cutting the material. This helps to ensure that the programming is correct, preventing any possible mistakes that could damage the material or the machine.
Once you have all of your axis zero’d, move the head up to a distance that is safely above your work that if you run your program it won’t cut your part. I for example usually choose 30mm. Then zero your Z axis and run your program.
Once your air pass is complete (or you see that there aren’t any issues) move the head off your part and bring it back to the original height (in my case -30mm) and zero your Z axis again.
<aside> ⚠️ Doing an air pass this way is good since it will also tell you if your spindle, coolant pump, and vacuum system are enabled.
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There is also a quick way to do a dry run without changing the Z axis zero. In this case the spindle won’t spin up, nor will the other linked systems turn on.
Move the head up so that the lowest cut in your program won’t hit your material (IOW safely above your material)
Press MDI:
Press Dry Run then Exit
Now rewind and hit start to do a Dry Run