Thoughts on cutting a pocket with a flat bottom rounded at edges?

[WillAdams (William Adams (Carbide 3D))]

There are a number of ways to do this, but most involve multiple pieces of geometry and usually 3 toolpaths, which need to be coordinated in terms of ordering.

Wrote this up a while back:

Pocket with rounded perimeter and flat bottom

as requested on support… Given an arbitrary shape which one wants to cut as a pocket and have a rounded shape along the perimeter and a flat bottom: [image] Start with a pocket down to the height where the rounding begins at: [image] [image] [image] Then, inset by the radius of the ball-nosed tool: [image] [image] Apply [image] assign a toolpath which starts at the bottom of the previous toolpath and cuts to the finished depth: [image] [image] Then assign a No Offset Cont…

which seems to work well, at least conceptually — so the basic form would be:

given an approximate design which one wishes to cut thus, select it:

and choose “Filet All”

with an appropriate value (at a minimum, the radius of the pair of tools which will be used)

Assign a Pocket toolpath to the desired depth using a square tool (to get the flat bottom):

then assign a No Offset Contour to the same depth:

using a ball-nose tool (to get the rounding at the edges)

The one drawback is that the geometry does not have the same dimensions as the actually cut pocket, but the simplicity makes up for it in my book.

Are there any unanticipated issues/concerns which would argue against this approach other than that?

[Redlander (Tim Jones)]

No argument at all, I use a bowl bit from WP’s to finish the pocket and counter cut. Hog out the pocket leaving 0.075” from full cut depth and offset from design by 0.01”. Swap to the bowl bit and run pocket tool path at full depth and same offset , then (inside) contour tool path to full dimension and depth. So, 3 cuts with two bits. I got the set of three of these and they cut exceptionally well, the limit is the 0.5” D. WP also has smaller bits with cut radius on them as well that could be used in your scenario.

Your process is faster for sure.