bioresources. com
PEER-REVIEWED ARTICLE
There were significant effects of the spindle speed, feed rate, and tool diameter parameters on the R a value and R z at a confidence level of 95% (Tables 2 and 3). The depth of cut had no significant influence on surface roughness ( i.e ., R a and R z ). There was no significant interaction between the model parameters (Tables 2 and 3). Table 3. Result of the ANOVA for R z Source DF SS MS F- value Sig. Spindle Speed_A 1 189.682 189.682 10.114 0.002* Feed Rate_B 3 351.119 117.040 6.241 0.000* Depth of cut_C 1 3.438 3.438 0.183 0.669 Tool diameter_D 1 120.651 120.651 6.433 0.012* A*B 3 16.875 5.625 0.300 0.825 A*C 1 31.356 31.356 1.672 0.197 A*D 1 40.677 40.677 2.169 0.142 B*C 3 126.655 42.218 2.251 0.083 B*D 3 44.833 14.944 0.797 0.496 C*D 1 23.866 23.866 1.273 0.260 A*B*C 3 34.675 11.558 0.616 0.605 A*B*D 3 41.559 13.853 0.739 0.530 A*C*D 1 0.911 0.911 0.049 0.826 B*C*D 3 35.587 11.862 0.633 0.595 A*B*C*D 3 13.563 4.521 0.241 0.868 Error 288 5401.280 18.754 Total 320 253768.290 Corrected Total 319 6476.725 DF: Degrees of freedom, SS: Sum of squares, MS: Mean square, *:p<0.05 To examine the effects of levels of these machining parameters, t-tests were utilized to determine whether the differences associated with the two spindle speed factors (18000 and 24000 rpm) and two tool diameter factors (4 and 6 mm) were significant. The t-test results for the effect of spindle speed and tool diameter on the surface roughness are presented in Table 4. The effects of spindle speed and tool diameter levels on surface roughness were different. The surface roughness value ( R a = 5.82 μm) at a spindle speed of 18000 rpm was higher than the surface roughness value ( R a = 5.565 μm) at a spindle speed of 24000 rpm (Table 4). This result suggested that the surface roughness decreased with increasing spindle speed. The surface roughness values increased as the tool diameter increased. The surface roughness value ( R a = 5.795 μm) at a tool diameter of 6 mm was higher than the surface roughness ( R a = 5.589 μm) at a tool diameter of 4 mm (Table 4). Table 4. Results of the t -test for Spindle Speed and Tool Diameter Level Parameters Level N Mean SS t _test P Spindle Speed 18000 160 5.818 0.838 0.627 0.008 24000 160 5.565 0.848 Tool Diameter 4 160 5.589 0.73401 11.689 6 160 5.795 0.94528 0.031 The effects of four different feed rate levels (2500, 5000, 7500, and 10000 mm/min) on surface roughness values were determined by the Duncan test, and the results are summarized in Table 5. There was no statistically significant difference between the effects of feed rate level 1 (2500 mm/min), level 2 (5000 mm/min), and level 3 (7500 mm/min)
İşleyen & Karamanoğlu (2019). “ Roughness of MDF ,” B io R esources 14(2), 3266-3277. 3271
Made with FlippingBook - Online catalogs