A high impact speed generates oblong machining tracks due to sliding impacts, as observed by Barletta and Tagliaferri (2006), Barletta et al. (2007a,b) and Yabuki and Matsumura (1999). Oblong machining tracks are evident in Fig. 16.
The machining tracks are rather long and occasionally characterized by deep scratches with adjacent ridges.Sometimes a prow of material occurs ahead of the scratch as a result of material accumulation in front of indenting abrasives impinging on theworkpiece surface at high speed. Therefore, the nature of the machining tracks confirms both material removal by micro-cutting and material displacement by microploughing.