After the "Ruled Surface5" feature as you can see below the two lines intersect and I can't figure out how to combine them or make it "smooth" and I think this is causing my "unable to thicken" error. Any ideas? I've attached the sldprt file.. Thanks in advance!
How thick are you trying to go? I had tried with 1mm and it worked but now I see that 2mm doesn't (even though it will preview!). I did a check for the minimum radius of curvature (which can be the cause of thickening problems) and it says there is a radius of .0016mm here:
I now think that the original surface loft doesn't blend well with the adjacent planar surface. I tried adding the edge of the planar surface as a guide curve to the loft, but then it gets a weird error (it says the profile line and the guide curve don't intersect).
But then if I roll back and measure from the profile curve to the edge it says that they DO intersect.
So I guess that is a bug. My guess is that the tangency is messing it up.
I replaced the surface loft with a boundary surface, so that I could select that edge and set tangency to the planar face, and that seems to have fixed it.
See if that will work for you. I've also attached my part in case you want to look at it.