October_AMP_Digital

A D V A N C E D M A T E R I A L S & P R O C E S S E S | O C T O B E R 2 0 2 0 1 7 (Figs. 5g-h; Triboconstituents B and D, Table 2). The evidence presented indicate that the formation of trans- fer films during testing also has an effect on the tribological behavior, Fig. 4 — Plot of (a) µ mean and (b) WR of PLA-based composites as a function of PLT. Fig. 5 — SE SEM images of (a) PLA surface and (b-c) corresponding Al 2 O 3 surface, (d) PLA-bronze surface, (e) BSE of the same area and corresponding alumina surface in (f) SE, and (g) BSE of the same region during tribology testing against alumina (all samples printed using PLT of 0.2 mm). TABLE 2 – EDS SUMMARY OF DIFFERENT TRIBOCONSTITUENTS Composition C O Si Cu Sn A 22.7 ± 4.6 4.18 ± 0.31 0.94 ± 0.06 67.4 ± 5.17 5.14 ± 0.24 B 7.29 ± 0.89 2.19 ± 0.34 x 85.6 ± 0.77 4.89 ± 0.03 D* 36.9 13.4 0.57 42.6 2.55 *Single data point was used (a) (b) (c) (d) (e) (f) (g) where the formation of lubricious tribofilms lowered the µ mean . Com- paratively, PLA-Fe and PLA-Cu had µ mean in the range of 0.51-0.56; the WR of PLA-Fe decreased from 5.9 x 10 -4 to 1.9 x 10 -4 mm 3 /Nm, while in PLA-Cu, the WR decreased from 6.3 x 10 -4 to 4.6 x 10 -4 mm 3 /Nm as the PLT was in- creased from 0.1 to 0.4 mm. The µ vs. distance profiles of these tribocouples were also stable compared to the PLA/ alumina tribocouple (Figs. 3c, d). Ertane et al. also observed that the addition of biogenic carbon in PLA stabilized the µ vs. distance profile [21] . In the literature, detailed studies of tribofilms formed during tribologi- cal studies of 3D-printed samples are not well reported. Currently, we are per- forming detailed studies to understand the effect of PLT on mechanical perfor- mance and other physical properties. However, at this juncture, we can pro- pose that the triboactive behavior of FFF-printed samples can be tailored by adding metal and ceramic particles. Based on the presented results, we can also propose that FFF-printed samples have potential in diverse triboactive ap- plications as we transition into digital manufacturing. CONCLUSIONS FFF is a promising technology that can be tailored for use by entrepre- neurs and small-scale businesses. More fundamental and applied research is needed in the design and development technologies for producing filaments. FFF is a highly adaptable technology for designing triboactive components by infiltrating the polymer with ceramic and metal particles. The current state of the art has successfully demonstrated its use at the laboratory scale. A further push for commercialization and pilot testing is recommended. As a case study, it was demonstrat- ed that various PLA-filled particles can enhance the tribological behavior. More specifically, PLA-bronze showed the best performance, where µ mean varied between approximately 0.45-0.47 in all (a) (b)