SUMMARY
In this work an effective simulator for a CNC milling machine is presented. It has been developed in EMC2, a free Opens Source NC software running in Linux environment, developed by an international community. It can be installed on a common PC and is able to: control a CNC machine; read part programs; display the tool path; send instructions to the CNC machine for the cutting process. In this work a new feature has been implemented, which can both display a 3D model of the machine and simulate all the motions of the movable parts of a real 3 axis end milling machine. This simulator lets the users not only verify the toolpath but also detect any possible collision by using the very computer which controls the milling machine. This system is very efficient and easy to use as powerful tool in Engineering education.