Hello, I am Emiliano Gasparovic, Print3D Ideas' owner. We have experience designing parts in Autodesk Inventor and 3D Printing them. We have built from fully functional parts, one-print assemblies, to artistic figures, so we're qualified for making the job right as you desire.
My offer is to make a free preview of the part, and if you agree, then you hire me and I'll deliver the file in .igs and in .dwg so as to make sure there's no problem when you send them to make the mold.
Please contact me if you have any questions.
Emiliano Gasparovic.