Development of mathematical models for surface roughness parameter prediction in turning depending on the process condition

This paper presents mathematical models for predicting Rz,Rp,Rv,Ra,RSm and Rmr(c) roughness parameters based on the kinematical-geometrical copying of the cutting tool onto the machined surface. The feed f, the radius rε and the angles λs,γo,κr have been used as input parameters in mathematical models. In order to increase the mathematical models' accuracy, as well as their practical applicability, this paper proposes connecting the R-parameter prediction models with the condition of the surface roughness formation process. The parameter of statistic equality of sampling lengths in surface roughness measurement (SE) has been used for this purpose. The proposed mathematical models were verified using two different CNC lathes, working pieces made of the material 42CrMo (EN), using finishing inserts. The paper provides the theoretically calculated values, the measured values and the percentage differences between them for the considered R-parameters. The paper proposes an algorithm of steps for predicting and realizing the considered roughness parameters for industrial purposes.