OBRABOTKAMETALLOV TECHNOLOGY Vol. 26 No. 4 2024 a b c Fig. 4. Roundness error varying with a) cutting speed, b) feed, and c) number of passes It can be seen that the maximum microhardness, lower surface roughness and roundness error can be obtained by roller burnishing under NFMQL cutting condition compared with dry roller burnishing. The microhardness and roundness error can increase with the increase of feed. And the increase of microhardness and decrease of roundness error can be seen with the increase of the number of passes. It can be seen that the increase of feed leads to contradictory responses for surface roughness and microhardness. A compromise between roundness error and microhardness and lower surface roughness can be obtained by using a feed value in the range of 0.18–0.22 mm/rev. The surface roughness can decrease with the increase of the number of passes. However, no signifi cant benefi t is observed in reducing the surface roughness beyond the use of four passes. The roundness error can be minimized by using more passes. Similarly, the maximum microhardness can be obtained by using more passes. Tables 5–7 show the ANOVA fi ndings for the F-values of surface roughness, microhardness, and roundness error for roller burnishing under dry and NFMQL cutting conditions, respectively. Referred to in [20], the ANOVA examined the responses for roller burnishing under dry cutting conditions. The F-value is highlighted to indicate the factors that signifi cantly infl uenced the responses. Tables 5–7 also include the percentage contributions of the various elements, which are calculated by dividing the F-value of each element by the F-value of the entire element. Table 5 shows that under dry conditions, the surface roughness is primarily aff ected by the higher order of feed (contribution of about 30.76 %), the higher order of cutting speed, and the interaction eff ects Ta b l e 5 ANOVA for surface roughness (Ra): F-values and % contribution of diff erent parameters Elements Dry NFMQL F-Values % contribution F-Values % contribution Cutting speed (V) 0.3382 0.07 4.2267 1.85 Feed (f) 6.3512 1.23 21.6487 9.46 Number of passes (N) 63.1738 12.25 11.2517 4.92 Interaction V x f 12.7024 2.46 2.8334 1.24 Interaction V x N 81.8517 15.88 5.2688 2.30 Interaction f x N 21.7218 4.21 0.0234 0.01 V 2 103.2749 20.03 45.6632 19.96 f 2 158.5728 30.76 53.2904 23.29 N 2 67.5406 13.10 84.6219 36.98 Total F-value 515.5274 100.00 228.8283 100.00 * Signifi cant elements are shown as underlined and contributions are in bold-case.
RkJQdWJsaXNoZXIy MTk0ODM1