Document Type

Thesis - Open Access

Award Date


Degree Name

Master of Science (MS)

Department / School

Mechanical Engineering

First Advisor

Todd Letcher


This project focuses on developing a high strength composite material for largescale 3D printing applications using recycled materials like High-Density Polyethylene (HDPE) and Steel 430. This material has applications for in-space manufacturing (the Moon or Mars) as well as large-scale manufacturing on earth. In addition to creating a strong useful material, materials that are easily recycled, but are often not recycled, are used. Recycling plastic and metal reduces pollution, saves resources, reduces waste going to landfills, and prevents the destruction of habitats from the polymerization of new plastic and similarly mining new ore. The percentage of HDPE generated from recycled waste is less than 21% annually. In the same way, steel makes up the largest category of metals in the municipal solid waste and industrial waste streams. Although the usage of steel in construction sites is very common, the challenges of 3D printing with recycled steel reinforcements are extreme, because of the size and scale of most waste steel products. In this work, material samples are manufactured using a vacuum oven molding process and varying ratios of steel pins to HDPE polymer pellets. Mechanical properties including elastic moduli, ultimate strength, flexural strength, % elongation at break, and surface hardness were evaluated, and the results were compared to other proportions. Samples were also manufactured using a large-scale 3d printer to determine differences between molding the material and 3d printing the material.

Library of Congress Subject Headings

Three-dimensional printing.
Composite materials.
Plastic scrap.
Steel -- Recycling.
Recycling (Waste, etc.)

Number of Pages



South Dakota State University



Rights Statement

In Copyright