Tenson, even with a good vacuum, there may be a tendency for small parts to move after they are cut out. Leaving a couple of small tags where necessary does work wonders. with some plastics sometimes they try to partially weld themselves back together. I find that "climb milling" will usually ensure that the weld sticks to the scrap rather than the cut item. I am afraid that I can't give you any figures for the vacuum - suck it and see!!! G.