In order to increase the modeling power and productivity of CAD/CAM systems, demands for customization of CAD/CAM system increased. Customization of a CAM system involves making it easier to learn and use, adding new modeling features not supported in a general purpose CAM system, and providing parametric inputting mechanism. A customization from a commercial CAM system (OMEGA) has implemented for two dimensional free curve CNC glass scribing machine of medium size company in Cheonan. A CAD technician who has no CAM experience can operate this customized CAM system satisfactorily.