The effects of PLA color on material properties of 3-D printed components

As the number of prosumer printers has expanded rapidly, they now make up the majority of the 3-D printer market and of these printers those in the open-source lineage of the RepRap also have expanded to dominate. Although still primarily used for prototyping or hobbyist production of low-value products, the RepRap has the capacity to be used for high-value distributed manufacturing. A recent study found that RepRap printed parts printed in realistic environmental conditions can match and even out perform commercial 3-D printers using proprietary FDM in terms of tensile strength with the same polymers. However, tensile strengths of the large sample set of RepRap prints fluctuated. In order to explain that fluctuation and better inform designers on RepRap print properties this study determines the effect of color and processing temperature on material properties of Lulzbot TAZ deposited PLA in various colors. Five colors (white, black, blue, gray, and natural) of commercially available filament processed from 4043D PLA is tested for crystallinity with XRD, tensile strength following ASTM D638 and the microstructure is evaluated with environmental scanning electron microscope. Results are presented showing a strong relationship between tensile strength and percent crystallinity of a 3-D printed sample and a strong relationship between percent crystallinity and the extruder temperature. Conclusions are drawn about the effects of color and processing temperature on the material properties of 3-D printed PLA to promote the open-source development of RepRap 3-D printing.