J. Liermann

Bio: J. Liermann is an academic researcher. The author has contributed to research in topics: Burnishing (metal) & Honing. The author has an hindex of 1, co-authored 1 publications receiving 146 citations.

Roller burnishing of hard turned surfaces

Abstract: In a hard roller burnishing operation, a hydrostatically borne ceramic ball rolls over the component surface under high pressures The roughness peaks are flattened and the quality of the workpiece surface is improved When combined with hard turning, this process provides a manufacturing alternative to grinding and honing operations The studies determined optimum working parameter ranges Parameter settings were shown to be non-critical in this process, since constant surface qualities were attainable over wide setting ranges A second phase of the studies examined the improvements obtained for various original roughnesses Reductions of 30 to 50 % in mean peak-to-valley height Rz are, for example, achievable, depending on the original roughness Structure analyses and residual stress measurements were used to examine the effects of the process on the workpiece surface zone Hard roller burnishing transforms tensile residual stresses present in the surface zone after hard turning into compressive residual stresses Hard roller burnishing has no effect on the formation of white layers in the surface zone

Effects of working parameters on surface finish in ball-burnishing of hardened steels

Abstract: Burnishing is a chipless finishing method, which employs a rolling tool, pressed against the workpiece, in order to achieve plastic deformation of the surface layer. Recent developments made possible burnishing of heat-treated steel components up to 65 HRC. Features of burnishing include a good roughness (comparable to grinding), as well as improvement of mechanical characteristics of the surface (fatigue strength, corrosion resistance, and bearing ratio), due to implementation of compressive stresses into the surface layer. This paper will present influences of certain burnishing parameters upon roughness, for a hardened steel component (64 HRC).

Experimental techniques for studying the effects of milling roller-burnishing parameters on surface integrity

Abstract: Roller-burnishing is used in place of other traditional methods to finish 6061-T6 aluminum alloy. How to select the burnishing parameters to improve surface integrity (reduce surface roughness, increase surface microhardness and produce compressive residual stress) is especially crucial. This paper presents an investigation of the effect of roller-burnishing upon surface roughness, surface microhardness and residual stress of 6061-T6 aluminum alloy. The residual stress distribution in the surface region that was burnished is determined using a deflection-etching technique. Mathematical models correlating three process parameters: burnishing speed, burnishing depth of penetration and number of passes, are established. A Group Method of Data Handling Technique, GMDH, is used. It is shown that low burnishing speeds and high depths of penetration produce much smoother surfaces, whereas a combination of high speed with high depth leads to rougher surfaces because of chatter. The optimum number of passes that produces a good surface finish was found to be 3 or 4. The maximum value of compressive residual stress decreases with an increase in burnishing speed. The maximum compressive residual stress increases with an increase in burnishing depth of penetration and/or number of passes.