Tool Travel Height

I was trying to figure out how to change the tool travel height when its going over the top of the material. When cutting the tool is traveling to close to the material and hitting it at times. For instance. I am running a piece of corrugated. Warped pieces at times let go off the vacuum once its cut.
I have been search the forum I cant seem to find if someone has already answered this. I'm pretty new to this machine. I would appreciate any help. I have looked in the tool manager and the tools in Aspire. I cant seem to locate something to adjust it. I would rather the tool come up a inch above the material. Right now its at about an 1/8th. Thanks in advance