CNC MACHINE TOOL SAFETY FROM THE ASPECT OF HAZARD PERCEPTION BY OPERATING PERSONNEL

Abstract

Safety of machinery, including CNC machine tools, must be ensured in all phases of their life cycle. The operation and maintenance phase is the most important as it represents the longest period in the machine´s technical life linked to occurrence of work injuries. Every designer of a safe machine must consider also any reasonably foreseeable incorrect behaviour of the machine operator. The latest revision proposal of the Machinery Directive 2006/42/ES [EUR-LEX 2021] sets new requirements on solution of CNC machine tools safety. Aside from assessing the impact of cybersecurity on the machinery safety, the manufacturers will now have to take into account also the psychological stress arising from human-machine interaction. From the psychological point of view, the operating personnel of multifunctional CNC machine tools experience high level of stress when machining complicated and complex-shaped workpieces as the material often costs as much as 30% of the price of the machine; therefore, any mistake of the operator resulting in a nonconforming product causes high financial loss. Influence of various stressors on the operating personnel leads to their impaired concentration on the performed tasks, which may be accompanied by insufficient perception of the hazards associated with the machine operation and thus may lead to occurrence of work injuries. The presented paper discusses the factors that may put the operators of multifunctional CNC machine tools under psychological stress and analyses possible application of the virtual reality technology to assess the ability to perceive the hazards linked to such a complex machine on a group of university students representing both operators (beginners) and designers of a multifunctional CNC machine tool.