In this paper, a novel approach to the definition of universal machinability is presented. The machinability model is based on analysing the vector of the cutting process performance. The machinability of C45E steel was analysed and evaluated according to the developed machinability definition. As the machinability criteria, cutting force, intensity of tool wear and surface roughness were used. Analysis of machinability was performed using different cooling and lubrication conditions: conventional flooding, minimum quantity lubrication (MQL) and high-pressure jet-assisted machining (HPJAM). Technological parameters were adjusted to the semi-finish regime, with the use of the highest parameter values possible. During the research, cutting forces, chip shapes, tool wear and surface roughness were monitored and measured. The influence of different cooling and lubrication techniques and the relationships between process performance indicators on C45E steel machinability are analysed.
COBISS.SI-ID: 13279771
The development of cutting simulation still requires an improvement in the understanding of the frictional phenomena at the tool-work material interface. This paper introduces a method for a fast identification of friction and heat partition models, based on a special tribometer able to simulate wide ranges of contact pressures and sliding velocities, similar to those occurring along the tool-work material interface in cutting. The method is applied for a wide spectrum of work materials and lubrication conditions. Combined with an analytical post-treatment, this set-up provides a modelling of the frictional behaviour that may improve significantly thermal aspects in cutting simulations.
COBISS.SI-ID: 12859163
The influence of nanolayer AlTiN/TiN and multilayer nanocomposite TiAlSiN/TiSiN/TiAlN hard coatings on the wear behavior and cutting performance of carbide cutting tools was investigated in face milling of hardened AISI O2 cold work tool steel (∼58 HRC) at dry conditions. Characterization of the coatings was performed using nanoindentation, scratch test, reciprocating multi-pass wear test.
COBISS.SI-ID: 26697767
The purpose of the study was to verify whether the appropriate creative approach enables establishing a positive classroom climate in the elementary school and whether, consequently, lead to changes in the field of creative practices and flexibility of learning. The results of quantitative research show a positive impact of a workshop on the establishment of creative classroom climate, resulting in greater flexibility and creativity of the students who attend the workshop.
COBISS.SI-ID: 1536145860
This paper is addressing the problem of under-representation of young people in general, and females in particular, in the fields of science, technology, engineering and mathematics (STEM) in Slovenia. It has two main objectives: (1) to identify which priorities male and female STEM students in Slovenia seek in their future careers, and (2) to identify different important factors (i.e. key persons, previous school and out-of-school experiences) that influenced their choice of studying STEM. The main data collection method was a questionnaire developed within the Interests and Recruitment in Science project group. The sample consisted of 861 males and 420 female undergraduate STEM students towards the end of their first year of higher education and thisrepresented 60.8% of the whole target population. For data analysis, basicdescriptive statistics with one-way analysis of variance was used.
COBISS.SI-ID: 4383959