Use of roughness probability parameters to quantify the material removed in plateau-honing

This paper presents a new methodology for quantifying the material to be removed in the finish honing operation of plateau-honing using the roughness probability parameters to obtain a specified surface roughness. An estimated Abbott–Firestone curve is obtained, starting from the specified roughness values, which are defined by the roughness probability parameters: the transition bearing ratio (Rmq), the valley roughness (Rvq) and the plateau roughness (Rpq). To evaluate the accuracy of probability parameters for estimating the Abbott–Firestone curve, a series of cylinders were machined via plateau-honing under different conditions. The difference in area between the experimentally obtained curve and the estimated curve, generated from the measured values of Rmq, Rvq and Rpq, was then calculated. This difference was found to be sufficiently small to enable the use of probability parameters and of the estimated Abbott–Firestone curve. In the experiments performed, different grain sizes were used for the rough strokes (64, 91 and 181 [FEPA standard]), and a grain size of 20 was used for the finishing strokes. The roughness of each cylinder was characterised by measuring roughness at nine different points. The average Abbott–Firestone curve of the nine curves was then determined once the extreme curves had been eliminated according to Chauvenet’s criterion. The Abbott–Firestone curves obtained from the experiments were averaged by using as height reference the heights of Abbott–Firestone profiles corresponding to 92.5%, 95%, 97.5% and 100% of material. The resulting average curve was compared to the estimated Abbott–Firestone curve. The difference in area between the average curve and the estimated curve was calculated. The smallest difference in area between these curves was found for the reference profile height corresponding to 97.5% of the material. This difference was found to be sufficiently small to enable the use of the probability parameters and of the estimated Abbott–Firestone curve. The average differences in area were 9.2% for a rough grain size of 64, 2.1% for a rough grain size of 91 and 2.3% for a rough grain size of 181. The difference in area between the Abbott–Firestone curve corresponding to the rough honing and the estimated Abbott–Firestone curve corresponding to the finish honing is proportional to the quantity of material to be removed in the finishing operation. This methodology will be used as a preliminary step in future work aimed at predicting the parameters that control the process as a function of the specified roughness.