Swept Cut Normal To Sheet Metal

Hi there!

I'm trying to cut a open through a sheet metal part based on a swept/spiralling tube.  It's a bit hard to explain what I would like to accomplish, but here goes:  I would like to end up with a cut that is normal to where the tube meets the sheet metal on the underside, as well as where the tube exits on the top surface of the sheet metal.  I tried cut with surface but the result is not 'normal to'.  I also attempted to use the 'Intersection Curve' to create a sketch I can cut 'normal to' with but this only gives me half of the result I'm looking for.  In the example attached, the cut is normal to where the tube exits the top surface.  Any suggestions would be much appreciate!

Thanks,

Paul

SolidworksSheet Metal