Abstract:

Computer numerically controlled (CNC) machine tools are modern manufacturing equipment able to process complex parts with high accuracies. The most common CNC machine tools are milling and turning centers and consequently, the manufacturing operations unfolded on these machines are cutting operations (milling, turning, drilling, boring, tapping, threading).

Because CNC cutting machine tools are used on a wide scale, practically any technical university around the world has introduced in the curriculum for mechanical and/or manufacturing engineers, at bachelor level, specific courses for designing technologies and programs for them. Moreover, some of these courses are divided into manual programming techniques and computer aided programming techniques and taught during more than one semester.

However, there are two special categories of CNC machine-tools, which usually are studied only as chapters in a course for CNC cutting machine tools, or are not studied at all. The first category includes the CNC profiling machines, machines which process parts by means of an energy beam. The energy beam could be a laser beam, a plasma beam, an oxy-gas flame or a water jet. The second category includes the CNC punching machines, which process sheetmetal parts by means of plastic deformation, using specific tools (such as punches).

One could say that because the manufacturing processes on these machines involves only two-dimensional movements, the kinematic and control systems of the machines is simpler than cutting machines kinematics and control systems. However, the use of these machines raises a set of specific problems which an engineer has to be able to solve. First, the technologies, either for profiling or punching are very different than cutting technologies. Second, the optimal placing of the parts on the sheetmetal workpiece (the nesting process) is very important and nesting algorithms is another specific issue when using and programming these machines. Last, but not least, the CAD/CAM software packages for these machines and technologies are very different form the ones specifically designed for cutting processes and require specific training.

At „Lucian Blaga” University of Sibiu, starting with 2010, a Master programme, entitled „CAD/CAE/CAM systems for plastic deformation” was implemented. A specific course named “Alternative equipments with numerical control” was introduced in the curriculum, and its main topic is the study of CNC profiling and punching machine. In the first chapters of the course, the structure and kinematics of these machines are introduces. The following chapters are dealing with the materials and technologies for these machines. The last part of the course is dealing with programming techniques, manual and computer-aided (CAD/CAM techniques). Nesting algorithms are also studied in this part. The applications are unfolded both in the companies which own such machines and within the laboratories within the university, which are equipped with computer networks and specific CAD/CAM software.

Keywords:

CNC profiling machines, CNC punching machines, Master programme.