G. Petropoulos

Surface Texture Characterization and Evaluation Related to Machining

Τhis chapter is aimed at providing current knowledge on the association of surface texture with machining, along with recent advances in surface characterization and evaluation. Various texture parameters, adopted by ISO standards or not, are described and their distinctive power is considered. Arithmetic parameters, statistical and random process functions serve as measures for rendering in-height and inlength surface characteristics and allow multiparameter analysis of the surface, something quite necessary under current high requirements for precision and operation. Theoretical models for roughness parameters and experimental trends with regard to machining conditions are discussed. Isotropy of machined surfaces is also considered and methods for surface typology are finally discussed.

Selecting subsets of mutually unrelated ISO 13565-2: 1997 surface roughness parameters in turning operations

Due to the complexity of machined roughness profiles and the fact that different surface characteristics exist in view of function, a multi-parameter analysis of roughness is recommended by international surface metrology standards, as well as by recent research projects. A multi-parameter surface analysis according to ISO 13565-2:1997 standard is performed on longitudinally and face turned surfaces of Ck60 steel over a wide range of feed and cutting speed values in order to stablish subsets of mutually unrelated roughness parameters; each one of them would describe different features of the surfaces with the criterion for this purpose being insensitivity to cutting conditions. The correlation of each parameter considered is examined with the machining conditions; statistical regression models with varying correlation coefficients are developed. It is concluded further that a minimum concise set of independent parameters towards turning process control and research would incorporate Ra, Rsk, RRku, and RDelQ. [Received 3 November 2005, Accepted 7 January 2007]

A surface roughness analysis in turning of polyamide PA-6 using statistical techniques

This work is aimed at studying the impact of cutting conditions (cutting speed and feed) on surface roughness in turning of Polyamide PA-6, using two different cutting tool materials namely, Polycrystalline Diamond (PCD) and K15 cemented carbide. By applying Response Surface Methodology (RSM) and Analysis of Variance (ANOVA) to the experimental data, predictive models are developed exhibiting excellent correlation and revealing that feed exerts the strongest influence on roughness, whilst cutting speed has a secondary effect. On the other hand the PCD tool tends to provide better finish. These findings permit optimised selection of cutting conditions and tool materials.

Analysis and optimization of dynamically loaded porous metal sliding bearings under conditions of elastohydrodynamic lubrication

Purpose – This paper aims to develop a simulating model of a journal porous metal bearing under elastohydrodynamic conditions and combined (radial, friction and thermal) load distribution and to carry out structural optimization.Design/methodology/approach – The structure analysis is carried out for each kind of load separately and for the combined load distribution of the bearing, where a dynamically loaded porous metal bearing is simulated. This simulating model is developed by finite elements method using the structure analysis module of the CATIA V5 software. Further, a parameter optimization of a porous metal bearing is presented considering the elastic deformations of the bearing shell.Findings – It is revealed that the bearing, even at points with maximum displacements, could not reach the mounting clearance value during its operational life. Relatively small bearing dimensions produce very high values of eigenfrequency response (over 150 kHz) and common dynamic loads met in all sorts of sliding be...