(ORNL: Oak Ridge, TN) -- Researchers at the U.S. Department of Energy (DOE) Oak Ridge National Laboratory (ORNL) and their collaborators received a 2026 Award for Composites Excellence (ACE) Award for developing a large-format, 3D-printed, water-soluble polymer mandrel for manufacturing lightweight, linerless Type V composite pressure vessels. The vessels store hydrogen, compressed natural gas, nitrogen, and helium for the aerospace, defense, transportation, and energy sectors.

The project, “Novel Water-Soluble Large Format Additive Manufacturing Mandrels Enabling Type V Gas Storage Tanks,” received the ACE Award in the Equipment and Tooling Innovation category. ORNL collaborated with Infinite Composites, JuggerBot 3D, and Oklahoma State University on the technology.

“Type V linerless composite pressure vessels represent the next frontier in lightweight, high-pressure gas storage, but their manufacturing remains extremely challenging, particularly when it comes to producing and removing complex internal tooling,” says Ahmed Arabi Hassen, group leader for composites innovation at ORNL. “Our water-soluble, 3D-printed mandrels represent an important step toward overcoming this barrier and enabling scalable, cost-effective manufacturing of Type V vessels. This achievement demonstrates how advanced manufacturing and strong industry partnerships can help bring these technologies closer to commercial reality.”

Type V pressure vessels are made entirely from composite materials and don’t retain an internal liner. The award-winning approach uses large-format additive manufacturing to print a temporary mandrel from a specially formulated water-soluble polymer. Carbon-fiber is wound around the mandrel, and after the vessel cures, water dissolves the temporary tool, leaving the hollow composite pressure vessel. A gas barrier coating is then applied.

The linerless design reduces weight and eliminates liner failures, while the 3D-printed mandrel replaces costly metallic or mechanically complex collapsible tooling. The approach can also eliminate solvent-based removal, shorten lead times, and provide greater flexibility to manufacture large or complex shapes with high dimensional accuracy.

The ORNL portion of the research was conducted at the DOE’s Manufacturing Demonstration Facility (MDF). The MDF is supported by the DOE’s Advanced Materials and Manufacturing Technologies Office and acts as a nationwide consortium of collaborators focused on innovating, inspiring, and catalyzing the transformation of U.S. manufacturing.

The project was supported by the DOE’s Office of Critical Minerals and Energy Innovation.