Not sure why I’m geting chatter. 1x DOC (6.35mm), 2 flute upcut carbide, baltic birch. Iv’e tried 18k-23k RPM with little difference. Double sided tapes and clamps on the edges. Nearly brand new bit.
A bit disappointed as I looked at Winston’s video and figured 2400mm/min (100IPM) is a no brainer at full DOC. ( Shapeoko Pro Testing in Plywood - YouTube ) and that was with a downcut, which is typically slower than an upcut.
Additionally, this is an adaptive toolpath, which should be even easier than Winston’s video which is a contour and the most challenging.
Cuts are OK but could be better. I can see and feel the router/mount actually moving with the chatter. The bit was hot after cutting which is not surprising as my understanding is chatter leads to friction and a short tool life.
The tape is to hold the speed dial in the same place
Have you verified that your machine is sound mechanically? No loose fasteners, belts are properly tensioned, pulley set screws are tight, etc.
Have you tried matching Winston’s feeds and speeds? His chipload is double yours and could work better.
Like Winston says, cutting wood is always a little noisy but I do hear a little chatter in your cut. Different plywoods, particularly the high layer count ones, can be a bit harder to cut. Try reducing your depth by 20% and see what happens.
At and up to 3000mm/min the chatter was far worse. The plywood I’m cutting would be the same layer count as his, it’s Baltic birch. He goes up to 1.5x DOC even at 100IPM. I’m miles from that.
Yeah mechanicals are good. I did re-tighten all the rails as the fasteners because a bit loose. I did tighten the belts as per SO recommendations. I could tighten up the X more but I am weary to overtighten.
Winston’s plywood appears to be 3 layer plus the 2 veneers. It is difficult to see from your video but it looks like yours is at least 5 layer plus veneers. It could also be using a much more dense wood for the inside layers of your plywood. If the chatter was worse at the higher feedrate, I would suggest reducing your depth. If you want to get back some speed, try using a 3 flute with the appropriate feedrate increase.
Once the belts are at minimum required tension there’s no further benefit from adding more static tension to them, it doesn’t change their tension modulus and it causes premature wear.
Do you need to do the full adaptive clear for those round holes? That’s a lot of wood to cut and it might be faster to just run a contour around the inside edge of the holes with tiny tabs left at the bottom (or none at all if you are using tape / superglue workholding).
@LiamN There’s definitely multiple ways to do things. Tabs would work with finishing, however, currently after those holes are made, I put clamps inside to really secure the workpiece, as the double sided tape can kind of end up anywhere. This is less about the best way to CNC, and I’m open to suggestions of course, but more about the mechanicals of the Pro, and how Winston can obtain a far more aggressive cut.
He wraps up at 9.53mm (1.5x DOC as the tool diameter) with a full contour path which will see a ton of engagement along the tool. I’m at 1x DOC (6.35mm) and adaptive with chatter, and reduce feeds to 50% of his and still get chatter.
