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.

This paper presents the application of an experimental method for determining the numerical values of the machinability factors of medium alloy carbon steel in the drilling process. Research conditions are defined, including tools, machine, and machining parameters. The experiment was performed according to a two-factor orthogonal experimental plan, and the values of cutting forces were monitored using a dynamometer through other elements of the information measuring system. Cutting forces were also considered in relation to the drilling depth.

Drilling is most often associated with hole-making. The surface roughness parameters represent a measure of surface quality, and it is mainly influenced by the cutting process parameters (cutting speed, feed rate, drill diameter), tool geometry, tool material, tool type, type of processing, coolant and lubricating fluid, tool machine and type of work piece material.

The purpose of this paper is to explore the effects of drilling parameters such as; cutting speed (vc), feed rate (f), drill diameter (d) and drill point angle (θ) on the surface roughness. There are different parameters used to estimate the severity of the surface roughness (Ra, Rz, Rq and Rt). The arithmetic average deviation Ra is commonly used for finish surface processing. The experimental plan was based on Box –Wilson Central Composite Design. First order model predicting equations for surface roughness have been established by using RSM methodology to collecting the experimental data, during machining of Ck45E steel according to EN 10083-1.1191 in wet drilling process, using HSS coated TiN drill tools.

Production of bulbs from flower crops is one of the most dynamic sectors in specific farming systems. Due to their intensive nature, a rapid change in growing conditions, as they tend to change more quickly than other traditional Bulgarian agricultural crops. To implement specialized farming systems the following important conditions must be available: – the availability of highly specialized staff, familiar with specific biological and physiological characteristics of flower crops, with growing technologies, harvesting, storagе and accelerated production of flowers; – the existence of universal and specialized machines and equipment; – аn environment оф propagation and storage, incl. laboratory facilities and outdoor production areas.