G. Muresan1, L. Morar1, R.E. Breaz2

1Technical University of Cluj-Napoca (ROMANIA)
2Lucian Blaga University of Sibiu (ROMANIA)
Nowadays manufacturing processes are unfolded on CNC (computer numerical control) machine-tools, which allow the user to manufacture complex parts, with high productivity and accuracy.

In order to drive the machine slides on the required toolpaths, a NC (Numerical control) code has to be generated, either manually or by using computer aided manufacturing software packages.

As a future manufacturing engineer or industrial engineer, the student from a technical university has to be able to manage a manufacturing process which involves the use of CNC machine-tools and CAM (computer-aided manufacturing) software packages.

The main problem when designing the curricula is how to balance between the amounts of knowledge related to CNC programming and the knowledge related to using CAM techniques in modern course content. Are the manual programming knowledge still useful in an environment where CAM programs are more and more efficient and user friendly? Furthermore, should the CNC programming courses include more information about the structure and control of CNC machine-tools or more information about technological processes and cutting regimes?
It was generally accepted that nowadays manual programming skills and advanced knowledge about machine structure and control are not as important as using CAM techniques skills and knowledge about manufacturing processes.

The work will present how the evolution of machine-tools, mainly the wide spreading of five-axis machine-tools has changed this idea. Five-axis machines have a very complex kinematics and using CAM techniques for generating the NC code requires an extended user input. Thus, in most cases the user has to define the machine kinematics, the limitations of each kinematic chain, the hierarchy between the machine axes. Moreover, the user has to fine-tune the post-processors, which are CAM modules used for adapting the NC (Numerical control) code for different types of CNC controllers.

The authors have proposed an integrated approach which combines theoretical notions of CNC programming with practical training, both as operator and programmer on a 3-axis CNC machine-tool. In this stage, only simple parts will be manufactured using programs made manually.
As a further step, the students are trained in using a CAM software package, simultaneously with practical training in programming and operating a five-axis CNC machine tool.

In the third step, the students have to build the 3D model of the machine, modeling each major component of the machine structure and assembling them in a 3D assembly. Finally, the kinematics of the machine will be defined and the post-processor will be tuned for a particular CNC controller.