3DDave the gap is also a concern I have. The two pieces are touching when the foil backer connecting them is cut. I will look into rotary cutters like many have suggested.
We do currently use a snap off tip style knife. The issue is that it is not very predictable as to when it will get dull...
The problem is the adhesive builds up on the cutting edge. That is why I was thinking if I could do something with that did not contact the foil we wouldn't have to deal with that issue.
As part of our process we apply an adhesive lined foil backer to one of our products. Currently we use a glorified utility knife and drag it across the product to cut the foil. This works great the first 50 or 100 times until the foil tears instead of cuts, wads up on the cutter, causing scrap...