Date of Award


Document Type

Open Access Master's Thesis

Degree Name

Master of Science in Materials Science and Engineering (MS)

Administrative Home Department

Department of Materials Science and Engineering

Advisor 1

Joshua M. Pearce

Committee Member 1

Julia A. King

Committee Member 2

Paul G. Sanders


The low cost 3D printing market is currently dominated by the application of RepRap (self-replicating rapid-prototyper) variants. Presented in this document are practical utilizations of RepRap technology. Developed are innovative processes to manufacture composite materials systems for thermal management solutions.

First, a laser polymer welder system is validated by quantifying maximum peak load and weld width of linear low density polyethylene (LLDPE) lap welds as a function of linear energy density. The development of practical engineering data, in this application, is critical to producing mechanically durable welds. Developed laser and printer parameter sets allow for manufacturing of LLDPE multi-layered heat exchangers

Second, newly introduced metal-polymer composite materials (e.g. copper-PLA, bronze-PLA, iron-PLA and stainless steel-PLA) were shown to influence the thermal conductivity (W/m·K) of the composite matrix. Increased volume percentage of metallic constituent was shown to increase thermal conductivity. Air void fraction, a resultant of the manufacturing process, reduced the bulk composite 3D printed component. No significant effects were realized dependent upon the metallic constituent morphology (i.e. flake-like vs. spherical).

Third, development and fabrication of a large format multi-head RepRap 3D printer displays the ability of large-scale manufacturing potential. Energy efficiencies are realized upon utilization of all hot-ends (i.e. the embodied energy of each printer movement (X, Y and Z)) and are simultaneously shown at each hot-end. Furthermore, multi-head format printers are proven to develop composite components. Utilizing a novel weaving and layering method 1000-series aluminum wire is embedded into a polyethylene terephthalate glycol modified (PETG) matrix. Parametric customized gcode commands allow for innovative manufacturing.

In total, laser parameter development, material characterization, custom machine fabrication and printing process development are quantified. The three presented projects demonstrate the engineering advancement of RepRap technology in application to thermal management solutions and composite material development.

Available for download on Tuesday, April 10, 2018