Result and discussion
In milling AISI 304 stainless steel, cutting forces Fx,Fy, Fz and torque Mz measurements were taken by the dynamometer as well as the measurements of the mean,
the minimum and the maximum of each force and torque.The machining parameters are the cutting speed of 80 m/min, the spindle speed of 1 273 r/min, the cutting depth of 0.5 mm and the feed rate of 64 mm/min in these tests. Fig.2(a) shows the plot of Fx versus cutting speed in the cryogenic and dry milling. The results show that in the cryogenic milling and dry milling, Fx increases slightly with increasing cutting speed. The maximum Fx in cryogenic milling is higher than that in dry milling. The average Fx in cryogenic milling is higher by 6.5% than that in dry milling. The change of Fy with cutting speed is given in Fig.2(b). It shows an increase in Fy in both the cryogenic
and dry milling. The maximum Fy in cryogenic milling is higher than that in dry milling. The average Fy in cryogenic milling is higher by 5.6% than that in dry milling. Also, Fy increases with increasing cutting speed. Fig.2(c) shows the plot of Fz versus cutting speed in the cryogenic and dry milling. The graph shows that Fz
increases with increasing cutting speed in the cryogenic milling and dry milling. The maximum Fz in cryogenic milling is higher than that in dry milling. The average Fz
in cryogenic milling is higher by 3.3% than that in dry milling.
The measured maximum cutting forces are comparable to each other. The maximum cutting forces are ordered from higher to lower as Fx>Fz>Fy in the milling of AISI 304 stainless steel. This order is proper to cutting distances. Fig.2(d) shows a decrease in Mz with an increase in the cutting speed. The maximum Mz in dry milling is lower than that in cryogenic milling. There is a difference of 7.9% in the Mz maximum values between cryogenic and dry milling. Multiple variance analysis is also applied to the
cutting force data obtained from milling AISI 304 stainless steel. The experimental data were interpreted by factorial design of 2×2×4 (2 cutting directions, 2 cutting
conditions, 4 cutting speeds). Only the main factors’ effects were considered in the variance analysis. The results of variance analysis of maximum Fx are given in Table 4. According to the results of ANOVA, the cutting direction and cutting condition are the
significant parameters affecting the Fx (P