Sweep Along Guide might be the easiest tool to do this.
Do a curve that matches the radius of the slot, then do another curve to the previous curve that matches the other radius. Then sweep a surface of these two and trim the solid. Not a tough one to do.
Thanks for your answer. But this part should be made in part modeling without using surfaces.
Why wouldn't you want to use surfaces? That command is in the Modeling application so nothing fancy is needed for this.
The Swept command you suggested is as much surfacing as is my method.
Thanks I will try in surfacing .
can you please upload that ugnx part model which you made ?