International Scientific Journals
of Scientific Technical Union of Mechanical Engineering "Industry 4.0"

In the knowledge society (KS) and ”Industry 4.0” (I4.0) in the 21st century and today’s rapidly developing world with a large number of important applications, one of the most advanced and growing areas of manufacturing technologies is micro- and nano-machining (traditional and non-traditional) and micro- and nano-aditive manufacturing. Certainly one of the most important technologies of micro and nano machining is micro drilling. Micro-drilling (MD or D) is type of machining (processing) technology used for the drilling of miniaturized parts of small diameter in micro-scale, i.e. diameter in a range of a few microns to several hundred microns. In this paper is given a brief description of the development of micro-drilling process, as well as the basic division of micro-drilling process.

The paper deals with an operating photovoltaic plant in Bulgaria. The wide application of photоvoltaic plants in the energy system is known. At the same time, subject matters about their normal functioning are fundamental. The goal of the paper set is to analyze data from the operation of a photovoltaic power plant , which is ultimately related to improving its behavior. Relevant conclusions have been dоne.