Experimental study of the relationship between the vibro-acoustic parameters of the grinding process and the macro-roughness of the treated surface

OBRABOTKAMETALLOV Vol. 23 No. 3 2021 technology To increase the reliability of the experimental results, each experiment with unchanged factors was carried out three times. Table 1 summarizes the data on the magnitude of the sound averaged from the three experiments. The data were graphically displayed in the form of point dependences of the sound level distribution on the amplitude-time plane (Fig. 2, 3). Having analyzed the acoustics graphs, two characteristic stages can be distinguished. The first is the intensive growth of the sound level. Here, the workpiece is processed with a GW profile formed by dressing. The duration of this stage depends on the radial feed rate of the GW. Grinding at the second stage is performed with a run-in GW. The sound level continues to grow; however, this growth is much slower than at the first stage. G. B. Lurie, in his works studying vibrations of a TS during grinding [16–18], justified the division of the abrasive grains wear cycle between dressings into three stages: –  initial – the period after dressing, when there is increased wear of the cutting grain peaks and grains defective in shape and unfavorably oriented break off; the bunch is removed from the surface of the GW. This stage is characterized by a short duration, which depends on the dressing and processing modes. – normal – the period characterized by the mechanical wear of the cutting edges of abrasive grains. Compared to the initial stage, the wear slows down, and worn areas are formed on the grains. In advanced modes, when the load on the abrasive grains is significant, we observe the splitting of larger particles from the grains, called self-sharpening. – emergency – the period when the wear of the abrasive grains again increases, partly due to an increase in the amplitude of vibrations. However, the wear during the emergency stage is much slower than during the normal stage. Ta b l e 1 Average sound level data for various process conditions Grinding wheel running time t, min Radial feed rate S r , mm/min 0.2 0.3 0.5 0.8 Average sound level β, dB 0.25 –54.67 –58.00 –62.67 –59.33 0.50 –52.00 –54.67 –59.33 –44.00 0.75 –48.67 –50.33 –47.33 –39.33 1.00 –50.00 –46.33 –42.33 –34.33 1.25 –46.67 –45.33 –37.33 –34.67 1.50 –45.33 –44.67 –34.33 –33.33 1.75 –42.33 –45.67 –33.67 –29.67 2.00 –42.67 –45.67 –34.67 –31.33 2.25 –41.00 –42.33 –34.33 –28.00 2.50 –39.67 –39.00 –31.67 –27.67 2.75 –41.33 –37.67 –32.67 –28.33 3.00 –39.67 –36.33 –32.00 –29.00 3.25 –38.00 –33.00 –31.67 –27.00 3.50 –37.33 –32.33 –30.67 –29.67 3.75 –35.67 –33.67 –32.00 –27.33 4.00 –34.67 –33.67 –32.00 –29.67 4.25 –33.67 –32.00 –32.00 –28.00 4.50 –34.67 –32.00 –30.67 –27.00 4.75 –34.00 –30.67 –30.67 –27.67 5.00 –32.00 –31.67 –31.33 –29.00