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Old 11-16-2020, 04:52 PM
cncdood cncdood is offline
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Default Unwanted ripple on baltic edges

I'm cutting with an onion skin method and am ending up with ripples in the edge as shown in this image. I've tried adjusting smoothing and tolerance to .0001 in Fusion 360 to no avail.

I'm using fairly new 1/4 amana downcut leaving .05 for a 1/8 amana compression to clean. The 1/4 roughing is a climb cut and the finishing is conventional.

Any ideas on how to get this smoother?
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Old 11-16-2020, 05:15 PM
Kyle Stapleton Kyle Stapleton is offline
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What are your feeds and speeds?
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Old 11-16-2020, 05:19 PM
cncdood cncdood is offline
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1/4 - 18k at 450ipm
1/8 - 18k at 180ipm
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Old 11-16-2020, 05:27 PM
Jim Becker Jim Becker is offline
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Have you tried it with just a 1/4" compression cutter with an allowance and a last-pass opposite direction or equivalent? A .125" cutter is going to be less stable than a .25" cutter as you push it around, even for a slight, finishing cut.
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Old 11-16-2020, 06:39 PM
Erik Land Erik Land is offline
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I agree with Jim, I’d be use it a1/4” at the very smallest unless there’s a factor we don’t know about. A 3/8 would be even better. Also, have you checked to see your node population? Too many nodes can give you the rough cut I see on your parts.
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Old 11-17-2020, 01:08 PM
guitarwes guitarwes is offline
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I concur with Jim and Eric. I usually cut .75" BB with a 1/4" downcut bit in a Climb direction leaving an onion skin, then the cut thru pass with a 1/4" compression in a Conventional direction. The edge is slick as snot.
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Old 11-17-2020, 02:10 PM
Jim Becker Jim Becker is offline
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Quote:
Originally Posted by guitarwes View Post
The edge is slick as snot.
That sounds like really moldy plywood...

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OP, the major point here is to use the largest tool you can for the cleanest cuts...the mass and strength will be a lot more stable. "Chatter", while certainly being possible because of the nature of a vector, is most likely from deflection/tool strength at the depth you are cutting.
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Old 11-17-2020, 02:55 PM
Kyle Stapleton Kyle Stapleton is offline
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I would slow my feeds down (240i/m), BB is way harder than your normal ply.
We cut it in two passes with a downcut 1/4" at 180i/m (we only have 2.2hp), one climb down to .03", and clean it up with a conventional -.02.
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Old 11-18-2020, 03:01 PM
cncdood cncdood is offline
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Ok I figured it out through the help of a local CNC guru and the problem was actually nothing suggested here.

Turns out my CAM software, Fusion 360, hates splines. The machine was cutting lines instead of acrs which explained the jerkiness.

To remedy, I used a Fusion plugin that converts the splines to polylines and then re-did the CAM on the resulting DXF. It's another step in the workflow, but the machine runs so much smoother and the results are perfect.

Fusion plugin is here: https://apps.autodesk.com/FUSION/en/...autostart=true
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