## RESEARCH AND ANALYSIS OF DYNAMIC PARAMETERS IN V-BELTS

Trans Motauto World, Vol. 2 (2017), Issue 6, pg(s) 235-237

In this work is presented research about main dynamic parameters that have influence in the efficiency of trapezoid belts (VBelts). Research is done in the testing machine with 3 wheels. Two main parameters analyzed are important dynamic parameters: Force of preliminary belt tightening (Fpr), and Coefficient of elastic slipping (Kes). Last coefficient is important factor for dynamic analysis of belt transporters while it defines clearly level of carrying capacity vs. defined force of preliminary belt tightening. Through laboratory testing has been researched influence of power that is transmitted and force of preliminary tightening in the coefficient of elastic slipping, with the aim to determine optimal limit of this coefficient. In practice it is recommended that values of this coefficient not to be higher than 2%.

## MATHEMATICAL MODELING OF THE INFLUENCE OF CUTTING PARAMETERS ANDTOOL GEOMETRY ON SURFACE ROUGHNES DURING DRILLING PROCESS

Machines. Technologies. Materials., Vol. 11 (2017), Issue 9, pg(s) 446-449

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.

## TOOL LIFE MODELING BASED ON CUTTING PARAMETERS AND WORK MATERIAL HARDNESS IN TURNING PROCESS

Machines. Technologies. Materials., Vol. 11 (2017), Issue 7, pg(s) 356-359

In this paper we have presented methodology for development of life prediction model for first order tool during turning of hardened 42CrMo4 steel at different levels of hardness. It is important to be able to predict and describe the tool life in regards to manufacturing costs during industrial production. Tool life is defined as the of cutting time that tool can be used. Cutting tools can be used when they do not reach tool life criteria and can produce parts with desired surface finish and dimensional accuracy. Flank wear of cutting tools is often selected as the tool life criterion because it determines the diametric accuracy of machining, its stability and reliability. Tool wear is defined as a gradual loss of tool material at contact zones of workpiece and tool material, resulting the cutting tool to reach its life limit. This paper investigates the tool wear of TiN coated tungsten carbide inserts under dry cutting, using the central composite design of experiments method (DoE) with three factors at three levels. By using the multiple linear regression analysis between cutting speed, feed rate and depth of cut, it determines the effects of cutting conditions on extended Taylor’s tool life equation.