Hi there,
This is Bogdan from Romania.
I'm a mechanical engineer, designer, modeler and inventor with over 15y experience in designing, modeling and effective manufacturing of different products, devices and systems which spans across multiple industries.
I could stitch the model for you and be sure it is ready for 3D printing.
Just send me the original file (autodesk inventor, solidworks, pro-e, etc) and point the issues.
If you'll send the stl or stp file will take longer, because will need to convert into another format.
If you need/like we could discuss more about the project via msg channel here.
I'll fix the model for you and i'll send a 3d pdf in order to inspect it.
if the model is ok, i'll send the exchange file (iges, stl, step)