Engraving small font - the bit digs deeper and deeper as the job goes on. 6040z

[lucan07]

Having seen similar problems with thin acrylic on several occasions that were put down to software issues which is why as a non machinist I got involved, I identified the cause in every case as the helix screwing action pulling material up or mill down I have noticed same thing happen with acryilic since I started to use a CNC flexibilty and its tendancy to grab the mill or get a little soft and sticky whichever cause it seems most likely to me. It just strikes me that this is another situation where the obvious has been discounted at the outset by poster a way to eliminate would be try a straight router bit no helix and see if problem still occurs.
"Material Table = very thin stickypad mounted to the aluminum CNC table (this is not likely causing the issue)"