Theoretical Roughness Modeling of Hard Turned Surfaces Considering Tool Wear

Abstract

Surface roughness is an important factor in metal cutting, and usually different surface roughness characteristics are used to control the quality of the machined surfaces. However, as the cutting tool wears out during the cutting process, the roughness values change. In most cases, theoretical roughness values are calculated without taking the wear characteristics of the tool into account. For this reason, the calculated and measured roughness values may differ from each other, and the tendency of their change may also be different. This paper presents a method for the determination of the theoretical roughness of hard turned surfaces considering the wear of the cutting tool. The purpose of the analyses performed was to show the effect of wear trace on the tool and the roughness of the machined surface and to give a possible method to take the wear into account when calculating the theoretical roughness values. During the investigations, the shape of the actual (worn) edge section of the cutting tool was recorded by an optical microscope, and the theoretical surface roughness values were calculated with that profile by a CAD modeling method developed earlier. Cutting experiments were conducted on a lathe machine with two similar cutting tools, one of them has significant tool wear, while the other was a completely new one. The calculated theoretical roughness values were compared with real measured roughness values, and the error of the estimates was between 8.7 and 68.3%, larger errors were found at lower feeds.

Modeling of the influence of the wear of the cutting wedge of the tool on the stability of the metal turning process

“…7) tends to form such wear of the wedge, in which the force preventing cutting does not increase. It may even decrease slightly, resulting in a slowdown of the vibration activity of the tool, which determines the future roughness of the workpiece [30]. In case of such, the cutting system achieves some stabilization of the second segment of the wear curve by through reducing the vibration activity, as well as by some minimization of the flank friction coefficient [13].…”

Analytical determination of high-feed turning procedures by the application of constructive geometric modeling

“…Due to the kinematic and geometric relations of the turning procedure, the surface-generating point of the cutting edge describe a helical curve on the workpiece machined surface, generating a periodically changing profile. Felhő and Varga showed, that increasing the feed rate leads to a more orderly generated surface [4]. There can be also problem with the roughness changes locally in surfaces with untraditional geometries, as shown by Matras et al in their study of curvilinear surfaces [5].…”

Evaluation of the Feasibility of the Prediction of the Surface Morphologiesof AWJ-Milled Pockets by Statistical Methods Based on Multiple Roughness Indicators

“…In most of these cases, the predicted surface topography is appropriately determined by considering the interaction between the cutting edge or edges and the workpiece material on a given toolpath, with the surface topography estimated by the material remaining after the action of the cutting tool [14,15]. As the final topography also incorporates the effect of other phenomena occurring during machining processes, such as chattering or tool wear, in some cases information from vibration measurements or worn tool geometry is taken into consideration in order to improve the accuracy of prediction and attempts to quantify other stochastic elements are also made [16][17][18][19]. However, in the case of processes with a higher influence of stochastic elements andwhere it is not possible to directly quantify the action of each particle, such as abrasive processes, the efficiency of these models is limited.…”