Influence of the Density of the Track Grid on the Surface Roughness in Raster Honing
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uence of the Density of the Track Grid on the Surface Roughness in Raster Honing K. R. Muratova, *, **, T. R. Ablyaza, E. A. Gasheva, and D. P. Ismailovaa aPerm
National Research Polytechnic University, Perm, Russia *e-mail: [email protected] **e-mail: [email protected]
Received February 2, 2020; revised February 2, 2020; accepted February 2, 2020
Abstract—The influence of the density of the tool’s track grid (the raster cycloid) on the surface roughness of a cylindrical surface is studied experimentally. The resulting mathematical formulas permit calculation of the height of the surface irregularities with variation in the density of the track grid in the course of honing by abrasive bars of different grain size. Keywords: raster honing, grid density, surface roughness, honing bars, grain size DOI: 10.3103/S1068798X20100184
In honing with raster motion of the tool, the influence of various factors on the roughness of the machined surface is similar to that in traditional honing. One of the main factors determining the height of the surface irregularities is the grain size of the honing bars. The surface roughness in honing is practically proportional to the size of the abrasive grains. Within the working range, changing the cutting speed and the pressure of the bars on the workpiece surface has no marked effect on the surface roughness [1–3]. Raster honing differs from traditional honing and vibrational methods in that the cutting motion is the result of two sinusoidal vibrations with different frequencies ω1 and ω2 (ω1 > ω2) and amplitudes А (azimuthal) and В (axial) in mutually perpendicular directions [4]. In raster honing, the microrelief of the machined surface is formed under the influence of the density q of the grid of machining tracks, which varies widely thanks to the azimuthal and axial tool motions. In the range 30°–60°, the characteristic angle of the track grid has practically no influence on the surface roughness. The difference between the longitudinal and transverse surface roughness is pronounced when the amplitude ratio of the tool vibrations В/А < 0.25. If В/А is close to one, the texture of the machined surface is isotropic. If the grid angle is close to zero, the surface roughness increases, and the productivity declines.
in the direction of trajectory formation. The grid density of the raster trajectory takes the form
1 q= 1 = , ω − ω v π P 2 1 2 A2 + B 2 + B ω1 + ω2 ω1 where A and B are the azimuthal and axial amplitudes; ω1 and ω2 are the azimuthal and axial vibrational frequencies of the tool (honing head); vВ is the tool velocity. We see that the mean grid density depends in a complex manner on all the parameters of the elementary motions forming the final raster trajectory. In raster honing, the grid density q (mm−1), which varies over a wide range, controls the final working trajectory. The height of the surface irregularities and the standard deviation of the profile, characterizing the uniformity of the microrelief are least when 0.9 ≤ ω2/ω1 ≤ 1 and the ratio of axial and
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