dahlgren/suregrave wizard 2000st help

hi guys

wondering if you lot could help i have been given the above engraver from a friend im using superpro 6 that came with it.

i have no knowledge of cnc milling, ive been playing around and designing some plates every time it goes to cut out its going right through the plastic plate and into the aluminium base! ive adjusted depth in superpro to no avail
and tried adjusting depth using the hand held controller to no avail always same depth.

thanks neil