Date of Award
Doctor of Philosophy
The 3 dimensional printing (3DP), called to additive manufacturing (AM) or rapid prototyping (RP), is emerged to revolutionize manufacturing and completely transform how products are designed and fabricated. A great deal of research activities have been carried out to apply this new technology to a variety of fields. In spite of many endeavors, much more research is still required to perfect the processes of the 3D printing techniques especially in the area of the large-scale additive manufacturing and flexible printed electronics.
The principles of various 3D printing processes are briefly outlined in the Introduction Section. New types of thermoplastic polymer composites aiming to specified functional applications are also introduced in this section.
Chapter 2 shows studies about the metal/polymer composite filaments for fused deposition modeling (FDM) process. Various metal particles, copper and iron particles, are added into thermoplastics polymer matrices as the reinforcement filler. The thermo-mechanical properties, such as thermal conductivity, hardness, tensile strength, and fracture mechanism, of composites are tested to figure out the effects of metal fillers on 3D printed composite structures for the large-scale printing process.
In Chapter 3, carbon/polymer composite filaments are developed by a simple mechanical blending process with an aim of fabricating the flexible 3D printed electronics as a single structure. Various types of carbon particles consisting of multi-wall carbon nanotube (MWCNT), conductive carbon black (CCB), and graphite are used as the conductive fillers to provide the thermoplastic polyurethane (TPU) with improved electrical conductivity. The mechanical behavior and conduction mechanisms of the developed composite materials are observed in terms of the loading amount of carbon fillers in this section. Finally, the prototype flexible electronics are modeled and manufactured by the FDM process using Carbon/TPU composite filaments and the FDM printer modified in Chapter 5.
The mechanical properties are sensitively affected by the morphology of additive materials such as concentration, size, type, and shape. The printing parameters such as fill density, temperature, nozzle diameter, and layer thickness are also influential factors resulting in changes in final properties of 3D printed objects. Thus, mechanical properties of the thermoplastic polymers, e.g. acrylonitrile butadiene styrene (ABS) and polylactic acid (PLA), as a function of fill density and printing temperature are studied in Chapter 4.
Chapter 5 describes a way to modify the FDM printer for multi-material printing of flexible composite filaments in order to make single-structured 3D electronics via FDM process. To achieve the goals, the dual-nozzle filament extrusion system is installed to the FDM printer and the part for filament feeding is modified in this chapter.
Received from ProQuest
Hwang, Seyeon, "Study of Materials and Machines for 3D Printed Large-scale, Flexible Electronic Structures Using Fused Deposition Modeling" (2015). Open Access Theses & Dissertations. 1072.