Honing is a superfinishing process that generates fine surface topographies with interesting tribological properties. However the control of the process requires highly experienced operators. The selection of proper stones (abrasive grit size and type) is decisive for reaching the target topography. Furthermore, especially in the case of a feed controlled process, the stone expansion must be in adequacy with the selected stone. This paper proposes to investigate the effect of the abrasive grit size for different stone expansions on surface topographies generated during the honing process. Honed samples are produced by a specific test bench reproducing the honing kinematics and recording process induced forces. In total, two hundred forty areal surface topography measurements are analyzed and discussed alongside with the force measurements. A systemic analysis of a wide range of roughness parameters is performed. Results demonstrate that the grit size has a significant impact on the final topography signature. Furthermore, even though expansion speed was doubled, no obvious influence was observed on the surface roughness parameters except one (isotropy Str). Based on these observations it is suggested that the expansion speed has a limited impact on the number of grooves generated. © 2022 The Author(s).

Topographies are one of the challenges for the development of the metal additive manufacturing promising technique. The article investigates multi scale topographies (from form to roughness) of as built surfaces generated by selective laser melting (SLM). Different building inclinations of samples were observed both for upskin and downskin surfaces with a wide range of measuring techniques. The two main aims are: (i) to make a critical review of measuring techniques at different scales, (ii) to enlighten the different surface generation phenomena (and the corresponding scale) occurring during additive manufacturing. The effect of heat treatment on each scale of the topography is also discussed. It is found that the focus variation technique is well suited for AM surfaces. Concerning the observation of the inclined surfaces, some parameters are emphasized as good indicators of typical signatures of AM surfaces: isotropy for the weld track component, the skewness and Rsm for the staircase effect, fractal dimension for the presence of partly melted particles. The different parameters studied helps to model and understand the different surface generation phenomena aforementioned. © 2018 Elsevier Inc.

The possibility to reduce the amount of cutting fluids from machining processes is actively studied by the industrials and researchers. Minimum Quantity Lubrication (MQL) is a solution towards cutting fluids reduction. This article investigates the consequences on friction coefficient induced by the use of MQL. A tribometer is used in order to simulate experimentally the tribological conditions encountered during machining. As the cutting speed increases a lower amount of oil is deposited on the rough surfaces. Depending on the MQL operating conditions and sliding velocities it is plausible to reach starvation by leaving the real rough contact partly dry. A model computing a starvation percentage by filling an estimated oil amount in a deformed topography correlates with the experimental results. © 2015 by ASME

The manufacturing and finishing (honing) of cylinder liners for the automotive industry is a constant challenge in order to reduce friction losses and oil consumption. A better knowledge of surfaces generated during plateau honing is then required for optimization of the process. Despite a well-known and controlled honing process, variations in surface roughness appear due to honing tool wear and need to be mapped and analyzed. The following paper proposes to map the variations in roughness by using confocal 3D measuring equipment able to inspect any area of a cylinder liner. Six motor blocks, each with five cylinder liners, were evaluated with 20 topography measurements per liner (giving six hundred 3D measurements in total). In addition to standard 3D roughness parameters, tailor made parameters extracting honing texture information are computed. The results show that only a few parameters (Spk, Ssc and Sk) do correlate with the honing tool wear specific to each cylinder. Tailor made parameters indicate similar results. Indeed, as the honing tool wears down, the cylinder liner surface gets rougher plateau or peaks and sharper asperities indicating that ploughing occurs instead of cutting. In future, experimental models could be built in order to perform production and functional optimizations. © 2015 Elsevier Inc. All rights reserved.

The manufacturing and finishing (honing) of cylinder liners for the automotive industry is a constant challenge in order to reduce friction losses and oil consumption. A better knowledge of surfaces generated during plateau honing is then required for optimization of the process. Despite a well-known and controlled honing process, variations in surface roughness appear at both global (due to honing tool wear) and local (TDC, middle stroke, BDC) scales and need to be mapped and analysed. The following paper proposes to map the global and local variations in roughness by using a confocal 3D measuring equipment able to measure and scan any area of a cylinder liner. Six motor blocks (five liners each) are evaluated with twenty topography measurements per liner. In total, six hundred 3D measurements of size 1×1 mm are performed and roughness parameters are computed. The results show that some parameters do correlate with the honing tool wear specific to each cylinder. Experimental models could be built. Furthermore surface roughness varies significantly over the axial length of the liners due to waviness deviations combined with a lack of flexibility of the honing tool in axial direction. © Published under licence by IOP Publishing Ltd.

The automotive industry and the design of engines are strongly ruled by performance and legislation demands. In the valve train, besides the main function (transformation of rotation to translation movements) to fulfill, new requirements in environmental demands and performance in terms of wear are leading to more and more detailed studies of the cams and rollers. Wear reduction studies for prolonging lifetime of these components require decreasing the scale of observation down to roughness. Among the different wear stages of a component, the running-in is a crucial period which will greatly influence the lifetime and performance of components. The aim of this paper is to analyze the topography variations observed during the running-in of a camshaft on a valve train rig test. A truck engine's camshaft is run under realistic conditions and 3D surfaces are measured before and after the test by using relocation techniques. By measuring the very same surfaces before and after the experiment, a deep analysis of the running-in effects on surfaces can be performed. 3D surface roughness parameters are used in parallel with new proposed methods of analysis. As a result, the mechanisms involved during running-in are emphasized and can be used for further simulations and optimization of the cam roller contact. (C) 2014 Elsevier B.V. All rights reserved.