Up-spiral bits work well for thicker materials but quickly de-laminates the plywood along the cut edge. We tried sanding them but just wasn't a worthy finish.
So today started with a short road trip to visit a man with a laser. After several hours of fiddling with getting my 3D cad to produce DXF files with 'hairline' lines we finally got some pieces cut that look as good as we wanted. Its costing us more than using our own machines but I feel it worth it.
The rest of the afternoon was spent cutting blanks of parts. We've got it laid out in such a way that we produce enough of 1-2 parts at a time for 5 kits. So today I cut the z-rod-clamps and the y-motor and y-idler parts. It took a few hours but only because I didn't trust my blank layout enough to leave the machine unattended. It also didn't help that the vibration caused one of the limit switches wires to break at the solder joint. Always wire your switches to break contact, that way if a wire breaks your machine will stop like mine did; always better to know before you need it!!!
The parts still need a little more hand sanding but have turned out wonderfully.
I run a cnc router at my work and what you need is a compression bit, they are upcutting for a small distance on the bottom and downcutting on the rest. They tend to burn the wood a lot when you plunge with them because the chips have no where to go. They also cost quite a bit more, but its the only way to go on a router if you need both edges clean and can't deal with rounding the corners afterwards. We only ever buy the 1/4" size, that will work with baltic birch up to 3/4", I seem to recall them being harder to find in smaller sizes and they are solid carbide so they get expensive quickly for larger diameters.
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