Milling stepped pattern with curved and flat Treads

[Anonymous]

Hello Everyone-

I need to mill 3 steps into an aluminum bar 2.75 x .472 x .160 inches high.

Machinist wants to use an oversized cutter such as a .375 end mill.

Tread of step 2 and 3 are curved (varies in Z axis). read 1 is flat.

I cannot get the large cutter to reliably go into the corners and/or follow all contours.

Any ideas? Inventor 2020 w/ CAM package. Part file and picture enclosed.

Please and thanks, Jim

[Anonymous]

Trying again with picture. 

[lenny_1962]

you wont have a perfect flat, slight elliptical surface, flat at the high spot but elliptical as it goes to the ends.

[Anonymous]

Thanks Len.  Without a fourth axis there will be a little compromising on the curve.

I am still perplexed why the cutter avoids the corners unless I reduce the stepover to a very small number.

Thanks, Jim

[Anonymous]

sketch added for Project toolpath toolpaths with 2D Contour and 3D Project

I tried a few more times. The square step is working well with 2D Contour and the gradual arcs picked up easily using a sketch to define tool path center with 3D Project. I did two passes for each level, one at .005" axial and radial offset and a second to finish at nominal.