Can't print with different line weights.

Hello.

I've just drawn a section for my work and I am trying to print it right but it isn't working. I've dran on diffferent levels and I've assigned different line weights for each but when I try to print and save my work as a .pdf all the drawing comes out in one line weight. Basically, my section looks like an elevation. I can't get my head around it. Can you help?

Thank you,

Claudia

Sectiune longitudinala sit .dgn