I am trying to achieve smoother cuts, see attached photo. Parameters of my current cut 1/2 Baltic birch plywood 1/4 inch diameter compression bit, new Plunge rate 300 mm per minute Spindle speed 18,000 RPM Feed speed 2200 mm per minute 4 mm tab thickness 8 mm deep, first pass as per manufacturer, needed to reach down spiral flute I have tried reducing feed speed and spindle speed, without causing burns In each test there is an audible thump when the Feed axis direction changes, or the spindle returns to the original starting point to close the shape. The router shifts slightly from the force of direction change. I have tightened the wheels using the eccentric bushing on each axis. How can I further reduce router shifting? How can I make smoother cuts?
Use an upcut bit for a first toolpath leaving some stock for a finishing path with your compression bit. First toolpath use a stepdown equal to half of the bit diameter. Second toolpath with the compression bit at full depth. Alex.
you still have a lot of backlash in your system, you need to rewatch the build video to make sure you are setting the eccentrics correctly. when you try to move the bit (power off) with your hand, how much movement can you feel?
Good information. Shouldn’t the first pass be a down cut to push wood fibers down? I have been considering a 2mm down cut pass then using the compression bit to insure an up cut on the bottom surface.
I’m sure that you are right. I purchased the machine used. I adjusted all of the eccentrics which improved the work but the is still visible movement when the router path changes. Larger circle diameter is always smaller because the router shifts toward the inside of the cut. I will watch the assembly video again to learn more. Is partial disassembly required? Do the eccentrics wear out?
Upcut will pull the chips out of cut area - especially important if the cut is a slot. The last thing you want is the cutting area clogged with chips. To clarify, the stock to leave I referred to was radial stock - ie in the waste part of the material. Given that a compression bit is much more expensive it makes sense to do most of the work with a cheaper bit, and not cause deflection by cutting too deep. I get what you are saying about starting the cut with a downcut, but you will get a better finish if you leave a small amount of material to be removed by a final, full depth, finishing cut - and better accuracy too. Alex.
No, flexible couplers are a must. But if the setscrews on the couplers rattled loose, they slip. Just check they are all tight and that the motor side grubscrews has one seated on the flat of the D shaped motor shaft
