Multi axis reduce corners radius inside box

[oliverU4NA2]

Hello everybody,

We are using a simultaneous 5 axis milling machine.

I have an item in a rectangular shape 18.2x6,3x8,2mm with an inner pocket cut through of 4.1x4.1mm.

The 4 inner corners have a radius of 0.5 mm

I need to reduce this radius to 0.2mm or less for a distance of 3mm from outside towards inside.

We have created geometries but every time we had the error message using Swarf and multi axis contours

Can anyone help me with the toolpath.

Have a great day