Try WiseVIEW, they have a free 14 day trial for CATIA V4 3D to IGES converter. It is a viewer and translator so don't be confused. Open file then export as iges.
Try out some translators that can convert CATIA to MasterCAM or EDGECam directly. There are also some third party translators available for translation. you can contact me if you need more details on translators.