OK, so I've been using my CNC for about a year. I've tried the shoe that fits over the router with the bristles. That only works good, in my opinion, if you are routing out a lot of sheet goods. I route guitar parts so I have lots of different contours and cut depth up to 2 1/2". For now I've just let it go, but the saw dust is literaly at my ankles. I tried putting a wide mouth funnel dust collection port at the end of the CNC table and have a large house fan at the front of the CNC table blowing toward the funnel. It worked all right, but was in the way as I had foam board screwed to the sides of the CNC table inside of the gantry. Which makes for hard setup. It didn't work perfect so I scraped it. I tried it with different angles with the fan, I even make a cover and blocked off the exhaust ports on the bottom of my Bosch router, because the Bosch has a very powerful fan blowing out the bottom, probably to clear the chips away. I tried it with it blocked off, full open and redirected with a piece of platic. The full open seemed to work the best keeping the dust blowing down onto the table so the large fan could kick it into the dust collector. Nothing I've tried work good enough for me.
So here's my solution. I started thinking that I needed something to follow the work piece as well as the Z axis. SO I made this in the picture. It's finished except for the bristles on the bottom, which should be here this week. What you're looking at is a 4" dust collection ABS plastic glued and reinforced with Hot Glue and attached to the underside of the router. Then a piece of easy flexible 4" dust collection hose glued to the inside of a 4" ABS drain waste pipe. Now that part moved up and down with the Z axis but the bottom is held in place by Loc-Line flexible line, usually used for directing coolant on machinery. The Loc-Line is bolted to base of the Z axis, which doesn't move up and down, and bolted to a plexiglass base. The plexiglass base will have the 4" hose hot glued to it and on the underside of that will be a 1" horse hair fine bristle.
So for setup I will have my work piece on the CNC then move the base so the horse hair is onto the piece. The base will stay in place and since it doesn't move up and down with the gantry it will remain at a constant height to the work piece, hopefully catching 90% of the dust. The Z axis can move up and down freely as the flex hose acts as an according to allow movement. Now it is able to go up and down completely to the same height I had before, meaning I don't really have to have longer bits. The bristles are horse hair so they are fine and very easy to bend. I didn't want hard bristles like those on the end of shop vacs, but I'll keep experimenting until it's good.
I do have to unscrew it, 2 screws, from the underside of the Z axis, but that only takes 5 seconds. Yes that's a pain in the....but this is really a prototype if it works I might machine it out of aluminum and make it pretty as well as strong which means I will add a quick release to the unit, I've already got it designed, its a pretty basic engineering item but will allow the unit to come off with a quick twist.
I would love feedback as well as anyone who has suggestions in design or function so I can refine this if it needs it.