Backup-Ring Optimization for High-Temperature and High-Pressure Applications Through Dynamic Composition Modification in Composite 3d Printing

Abstract

Abstract Performance optimization was demonstrated in thermoplastic sealing systems for oil and gas equipment using emerging technologies in 3D printing to manufacture multicomponent composite structures. A custom 3D printer was equipped with a patented print head designed for dynamic mixing of individual feed materials and paired with advanced print-planning procedures to enable fabrication of novel thermoplastic structures. Simple flat backup rings used in O-ring sealing connections were manufactured with numerous architectures including homogeneous carbon fiber distributions, consistent with typical commercial processes and products, and novel carbon fiber distributions unique to this study. Specimens were tested in a sealing configuration to determine performance. Backup rings made from polyether ether ketone with uniformly distributed carbon fiber at high concentrations result in lower peak extrusion pressures than do unfilled grades but have the advantage of lower permanent deformation during long periods of steady-state loading. Flat backup rings were produced with discrete regions of each unfilled and carbon filled grades of polyether ether ketone and polylactic acid to optimize extrusion pressure at failure and long-term creep which were found to be dependent on both the volume ratio and orientation of the two regions relative to the primary O-ring seal. Uniform distributions of carbon fiber were outperformed by at least one binary or functionally graded architecture having the same nominal carbon fiber content. This demonstrates the viability of on-demand 3D printing of backup rings and provides a novel means of simplifying multicomponent systems while simultaneously expanding the operating envelope and life expectancy of oil and gas equipment since extrusion resistance and long-term creep in thermoplastic backup systems are major factors influencing service ratings for temperature, pressure, and service life. Innovative technology and methods described in this study enable fabrication of novel composite structures that increase performance when compared to homogeneous materials manufactured through traditional molding processes. In addition to supporting fabrication of sealing components for rapid response in oil and gas equipment, this technique provides a means of improving the overall performance of sealing systems without an increase to the size or complexity of the sealing assembly.