Molybdenum Disulphide Modified Polylactide for 3D Printed (FDM/FFF) Filaments

Abstract

MoS2 is an additive used to improve the tribological properties of plastics. In this work, it was decided to verify the use of MoS2 as a modifier of the properties of PLA filaments used in the additive FDM/FFF technique. For this purpose, MoS2 was introduced into the PLA matrix at concentrations of 0.025–1.0% by weight. Through extrusion, a fibre with a diameter of 1.75 mm was obtained. 3D printed samples with three different filling patterns were subjected to comprehensive thermal (TG, DSC and HDT), mechanical (impact, bending and strength tests), tribological and physicochemical characteristics. The mechanical properties were determined for two different types of fillings, and samples with the third type of filling were used for tribological tests. Tensile strength has been significantly increased for all samples with longitudinal filling with improvement up to 49%. In terms of tribological properties, higher values of the addition (0.5%) caused a significant increase of up to 457% of the wear indicator. A significant improvement in processing properties in terms of rheology was obtained (416% compared to pure PLA with the addition of 1.0%), which translated into more efficient processing, increased interlayer adhesion and mechanical strength. As a result, the quality of printed objects has been improved. Microscopic analysis was also carried out, which confirmed the good dispersion of the modifier in the polymer matrix (SEM-EDS). Microscopic techniques (MO, SEM) allowed for the characterization of the effect of the additive on changes in the printing process (improvement of interlayer remelting) and to assess impact fractures. In the tribological area, the introduced modification did not bring spectacular effects.

Rotary Friction Welding of Dissimilar Polymer Rods Containing Metal Powder

“…Finally, a comprehensive database of the RFW of dissimilar polymer rods containing metal powder has been successfully established. Two different kinds of polymer filament, i.e., PLA-containing Al powder and Cu powders (Thunder 3D Inc., New Taipei City, Taiwan), were used to print welding specimens in a three-dimensional printing apparatus [25]. These two materials are commercially available.…”

“…The average peak temperature of the welded joint can be as high as 160 • C. However, the average peak temperature of the welded joint is the highest in the RFW of PLA-containing Cu powder and PLA-containing Cu powder rods. The average peak temperature of the welded joint can be as high as 144 • C.To investigate the bending strength of the welded parts under different ambient temperatures, the welded parts were put in ten different ambient temperatures, i.e.,25,27,30,32,34,36,38,40,43, and 45 • C. Figure16shows the bending strength of the welded parts under different ambient temperatures. The bending strength cannot be measured due to the test specimen becoming soft when the test specimen was placed above 45 • C. Two phenomena were observed.…”

Tribological Properties of Thermoplastic Elastomer Used in 3d Printing Technology

“…Recent years have brought significant development of the FFF (Kujawa et al, 2013) -Fused Filament Fabrication technology, which has significantly resulted in a drop in the prices of both machines for this process and the semifinished product -a plastic wire with a precisely defined diameter. This method involves feeding molten plastic through the so-called extruder that moves along a programmed path, feeding material at specific points, layer by layer, building the desired detail.…”