Principal Mechanical Engineer - Web Handling

Commonwealth Fusion Systems is on a mission to deliver the urgent transition to fusion energy. Combining decades of research, top talent, and new technologies, we’re designing and building commercially viable fusion power plants. And we're working with policymakers, suppliers, and many others to build the energy industry of the future. We’re in the best position to make it happen. Since 2018, we’ve raised $4 billion of capital, making us the largest and leading fusion company in the world.

Now we’re looking for more thinkers, doers, builders, and makers to join us. People who’ll bring new perspectives, solve tough problems, and thrive as part of a team.

We are looking for a Principal Mechanical Engineer specializing in Web Handling and Roll-to-Roll (R2R) systems to serve as the definitive company-wide technical authority for continuous material processing equipment. In this "First Chair" leadership role, you will shape the overall technical direction, architecture, and deployment of high-precision web transport systems operating in a variety of thermal environments. You will lead the execution of highly complex, ambiguous cross-functional initiatives that directly impact our core R&D and manufacturing roadmap.

Operating with complete independence, you will combine deep technical expertise in web dynamics and precision mechatronics, with strategic leadership establishing division-wide design standards, mitigating significant technical risks, and mentoring the engineering organization.

• Shape R2R System Architecture: Serve as the chief architect for next-generation roll-to-roll equipment, dynamic tension systems, precision accumulators, and high-speed winders/unwinders
• Research Advanced Winding & Unwinding Technologies: Actively research, evaluate, and benchmark next-generation web handling, winding, and unwinding equipment and technologies to inform tool architecture and roadmap decisions
• Lead Cross-Functional Strategy: Translate complex scientific R&D objectives into actionable engineering architectures, bridging mechanical design, process physics, electrical hardware, and closed-loop controls across multiple project groups
• Master Web Dynamics & Technical Risk: Drive advanced dynamic modeling, web physics analysis, and experimental validation to resolve critical web defects (e.g., thermal buckling, lateral drift, scratching, or tension transients) in flexible metal substrates
• Establish Division Standards: Institutionalize company-wide engineering standards, design guidelines, and testing methodologies for web handling, precision roller design, bearing selection, and mechatronics
• Drive Process & Tool Innovation: Pioneer novel mechanical concepts, dynamic guiding schemes, and non-contact web transport modules operating inside temperature zones
• Independently Manage Risk: Identify, evaluate, and mitigate high-impact technical risks across major equipment initiatives, establishing contingency paths and robust design margins
• Direct Strategic Vendor Partnerships: Audit, qualify, and direct global suppliers and contract manufacturers for specialized R2R sub-assemblies, precision ground rollers, custom surface coatings, and drive components
• Organization-Wide Mentorship: Actively coach and mentor Staff, Senior, and Junior mechanical engineers, elevating technical rigor, design review standards, and professional development across the discipline.

• Education: Master’s or PhD in Mechanical Engineering, Mechatronics, or a related field (or equivalent specialized industrial experience)
• Experience: 15+ years of proven track record as a recognized technical leader in the…