Markings in finish pass, from tabs > fusion360

Quick question, I just started using Fusion for CAM, and the tabs locations all have markings in the wall, caused during the final finishing pass (1 pass only at full depth).

Any tips on how to prevent this?

and btw this was the first real thing after my Z upgrade, pretty happy with the improved Z reliability…


Are you using square or triangular tabs?

square… was using triangular before, had a work come loose… but maybe just use bigger triangulars

The square will always tend to mark because the bit is stationary in X, Y whilst is moves up and down in Z, you’ll also get some deflection when it plunges down which may also take a bite out of the wall.

Taller triangulars may help, depends on the material which way to go.

I always try to leave the contour cuts that need the tabs until last as they really weaken the workpiece, even if things don’t break they can vibrate and give a nasty finish. Where I have a lot of contour to cut I run the toolpaths down to the last 3-5mm of the Z depth first by setting the bottom height to do the bulk of the cutting and them come back in a second pass of the contour going full depth with the tabs.

EDIT - those numbers are for wood not metal :wink:


Use triangle tabs. You can use a little bit of math if you want to find the square area of the rectangle tabs, and then use that same area for triangle tabs. Or you can just guess and make the triangle tabs bigger.

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Guessing is more my style :slight_smile:

(or drop the tabs and join the #TapeAndGlue family, just saying :slight_smile: )


nah, I’ll stay with tabs, just tried the triangles, and it’s pretty good now. Also I remove them on the router table, which is supper quick and easy.

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You can also run the pass TWICE, once with the bottom depth set at the TOP of the tabs, then full depth with the tabs, and a stock-to-leave of maybe 0.1mm. This will leave a small ridge around the edge tot he tab height. It is often not visible at all, and will clean up when you remove the tab stubs. It insures that the tool travel doesn’t change speed on the finish surface, which is, as @LiamN said, causes this. It changes the tool deflection.


I like your wall slat system. I have a metal building with C purlins and would have to install plywood on my walls with a treated 2x4 at the base shot into the concrete to hang stuff on the walls. Not that practical for me but in any shop if you cannot expand out them you must go up. I have two ten foot tall 32"x96" shelving units with 6 shelves and several six foot 24"x96" shelving units with 4 shelves as well as many metal shelving units. I like to use Banker Boxes to store things in. They keep the dust out and usually you cannot load them up so heave they cannot be lifted. The 10 foot shelves can hold the Banker Boxes 2 high and 4 in a row making a lot of storage space. Labeling is also important to find stuff when you need it.

Yeah, i really like the flexibility of french cleats all around my shop. For years I struggled in a tiny place, this year, with corona and skipped holidays I finally took the time to build myself a decent size shop, at least decent for Dutch standards, ofc everything is bigger in the US :slight_smile:

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