The Processing of Binder Jet Multi-Material 3D Printing to Improve upon Material Properties

Additive manufacturing methods are becoming more prominent in the world of design and manufacturing due to their reduction of material waste versus traditional machining methods such as milling. As their demand rises, a need to improve their methodologies and produce higher quality products arises. The technology to 3D print has been in around since the 1970’s, and thanks to Scott Crump as of 1989, it is possible to 3D print in layers to obtain a solid component. In today’s present time, we now can multi-material 3D print. However, even though we have the technology for multi-material 3D printing, standards in this field are severely lacking. Therefore, research on multi-material 3D printing and/or the combination of 3D printing filaments combined with nanoparticles is needed. One of the most common methods of 3D printing is fused deposition modeling (FDM). In this research, FDM was used to dope Acrylonitrile Butadiene Styrene (ABS), to introduce conductive properties for strain measurements. There are three pathways of research in this field. The first is to keep the binder used constant and change the nanoparticles tested. The second is to vary the binder used and keep the nanoparticles constant. The third is two use the same binder and nanoparticles throughout testing, but to vary the environment around them (such as temperature and humidity) to observe the environmental effects of curing and testing these samples. The research in this thesis took the first approach. N-Methyl-2-Pyrrolidinone (NMP) was used to bind the selected nanoparticles. In the first experiment, the researchers made their own nanoparticle laced binder, and bounded it to an ABS substrate. The second experiment introduced three new types of nanoparticles to test, nickel, carbon, electric paint. The third experiment repeated the methodology of experiment 1 and 2 and the environmental impacts it has on the conductivity of the samples. The fourth experiment analyzed the geometry of the printed pathways and their effect on conductivity. Using the results of experiment 1-4, strain gages were developed for part two of the study. Experiment 5 tested the conductivity of the strain gages, while experiment 6 studied the effect the various nanoparticles had on the stiffness of the 3D printed ABS strain gages. This extensive and detailed study concluded several points. The first point is nickel consistently showed to be the nanoparticle that yielded the least amount of resistance, and therefore, the highest conductivity. Second, layering multiple layers yields the best conductivity results. Third, the binder selected does indeed improve the performance of the nanoparticles. Fourth, the research was able to create individually isolated conductive pathways. Finally, the research demonstrated that the nanoparticles, when bound increased the stiffness of the ABS strain gages