Abstract
CNC (computer numerically controlled) machine tools are highly advanced technological systems, used to machine parts by means of metal cutting processes. Their structure and kinematics are very complex, involving accurate coordinated motions on three to five axes. Operating CNC machine tools is a complicated process, which can easily be affected by errors. Nowadays, safety systems and devices are developed in order to make this process safer and more user friendly. Modern CNC controllers are designed to deal with obvious sources of hazards, such as overloads (by means of various sensor systems) and collisions (by checking the NC code syntax and simulating it on the machine). However, despite of these safety systems, various unwanted events still occur during machining operations on CNC machine tools. These means that there are still certain hazards, not so obvious, which can severely affect the operation of CNC machine tools. This work tries to identify and hierarchize the above-mentioned hazards by using an AHP (analytic hierarchy process) approach. The results of the AHP emphasize which hazard has the biggest influence upon the CNC machine tools operation and consequently should be avoided. The results of this work could be used by the machine tools designers to develop new safety features for the existing CNC controllers. Also, the users of the machine tools could focus some of the safety measures during the machining process upon the most significant hazards pointed by the results of the research.
Highlights
IntroductionMachining parts on computer numerical control (CNC) machine tools, by means of milling (and/or other cutting operations) involves coordinated technological motions on three to five axes
Machining parts on computer numerical control (CNC) machine tools, by means of milling involves coordinated technological motions on three to five axes
There are on the market specialized devices, usually called “machine tool probes for component/workpiece setup” [28], which allows the user to setup the workpiece origin in a semi-automatic way, significantly reducing the possibility of errors. Even if their price is quite high, this study has revealed that reducing or even eliminating the possibility of inaccurate workpiece origin setup (IWS) occurrence makes the purchase of such devices an option to be taken into consideration
Summary
Machining parts on CNC machine tools, by means of milling (and/or other cutting operations) involves coordinated technological motions on three to five axes. These motions are controlled by means of a program, called NC code. Modern machine tools for metal cutting are equipped with various safety systems, which, if used properly, provides comprehensive machine operators protection [3]. Another work, presented in [15], indicates the integration between tool path generation and simulation as an effective approach to avoid collisions during five-axis CNC machining. With the increase in the complexity of the CNC machine tools (increase in the number of controlled axes, milling units equipping turning centers, high-speed machining), various new non-obvious hazards which can generate unwanted events during CNC machining have appeared. An identification of a hierarchy of these hazards is the main purpose of this work
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
