SBIR Phase II: Advanced Manufacturing of Ultra High Molecular Weight Polyethylene and Metal Hybrid Structures for Bicycle Spokes

The broader impact/commercial potential of this Small Business Innovation Research (SBIR) Phase II project is the replacement of steel with synthetic materials that are stronger and lighter. The beachhead market for this technology is the performance bicycle spoke market, which is a $180M global market. The potential benefits of this technology go beyond cycling because the polymer-to-metal interface has other potential applications. Cable assemblies are used in a wide variety of applications and industries such as industrial, aerospace, construction, and consumer goods. Advances in the termination of synthetic cable assemblies will enable the creation of higher strength-to-weight ratio cables and thereby increase efficiencies in transportation applications and improve the safety of tension based systems. An application of particular societal benefit is wheelchair wheels, where weight reduction increases portability for those with physical disabilities. Investment in termination technologies for high performance polymers will also help bridge the gap between polymer research and industry, helping society benefit from developments in polymer science occurring in academia. Finally, the ability to produce low-cost rope terminations will increase US manufacturing competitiveness because the majority of high-volume production is outsourced to low-cost labor markets. This Small Business Innovation Research (SBIR) Phase II project will develop an advanced manufacturing process for ultra high molecular weight polyethylene (UHMWPE) and metal hybrid structures for bicycle spokes. UHMWPE has a strength-to-weight ratio of fifteen times that of steel, but it cannot be utilized in many applications because of the difficulty in manufacturing high-strength bonds to metal. The primary objectives of this research are to automate the insertion and bonding of stainless steel rods inside the hollow cavity of braided fibers, and to automate the creation of eye splices. These operations require delicate manipulation of fibers in a confined space, and are typically performed manually. Instead, we will develop novel automatic machinery that will create these bonds, inspect the final product, and validate the strength with 100% in-process inspection. Another objective of this research is to develop a black surface coating process for braided UHMWPE fibers. To achieve this, we will identify a surface pretreatment procedure to add functionality to the non-polar backbone of UHMWPE, develop the coating chemistry, and create an in-line coating system that integrates with our manufacturing process. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.