OBRABOTKAMETALLOV Vol. 26 No. 4 2024 TECHNOLOGY a b Fig. 8. Eff ect of normal load (a) and speed (b) on PO2 wear a b Fig. 9. Eff ect of normal load (a) and speed (b) on PO3 wear Figure 9, a and b shows the infl uence of normal load and speed on the wear pattern for PO3 pin (printing orientation angle of 90°). A gradual increase in the wear was observed under normal load and variable speed. The minimum wear was recorded as 2,538 μm and the maximum wear was recorded as 3,106 μm. It is obvious from Figure 9, a and b that the slope of the wear versus speed graph increased by almost 21 % compared with that of the wear versus normal load graph. This indicates that the speed has a prominent eff ect on the wear pattern. A similar conclusion could be drawn from the exponent values of the equation (PO1) given in Table 4. It is observed form that above fi gures that PO1 material shows lower wear followed by PO3. PO2 exhibited the highest wear. The wear of FDM-printed PLA is greatly infl uenced by speed than normal load. A comparative analysis of the wear of all specimens was performed by maintaining a constant speed and a constant load. The equation given in Table 4 was used to determine the wear at the corresponding constant load. The eff ect of normal load on the wear pattern of specimens PO1, PO2 and PO3 at a constant speed of 600 rpm and the eff ect of speed on the wear pattern of specimens PO1, PO2 and PO3 at a constant normal load of 600 N are shown in Figure 10, a and b, respectively. The load varied from 400 N to 800 N with a constant increment of 50 N. It was observed that at constant speed of 600 rpm, PO1 material exhibited lower wear compared to PO2 and PO3. The lowest wear value for PO1 was 2,328 μm, while the highest was 2,513 μm. For PO2, the lowest wear value was 3,008 μm, and the highest was 3,407 μm. For PO3, the lowest wear value was 2,595 μm, while the highest was 3,023 μm. The wear rate increased steadily, increasing by 1.08, 1.25, and 1.11 times with increasing load for PO1, PO2, and PO3 specimens, respectively. PO1 exhibited a more stable wear pattern compared to PO2 and PO3. This was mainly due to the formation of a stable transfer
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