Senior Mechanical Design Engineer - Metal Structures

Company Overview

Mainspring Energy is revolutionizing power generation with the world’s most flexible and adaptable local power generation technology, the Mainspring Linear Generator. Commercial, industrial, and utility leaders are choosing Mainspring over traditional options like engines, turbines, and fuel cells to quickly and reliably deliver local power for EV charging, commercial facilities, data centers, and grid-scale operations. The Mainspring Linear Generator is fuel flexible, ramps up and down to meet demand, and utilizes a flameless reaction with near-zero NOx emissions.

Backed by top-tier investors including Khosla Ventures, Bill Gates, American Electric Power, Lightrock, and General Catalyst Mainspring designs, manufactures and delivers its products to customers across the U.S. today, and we’re quickly scaling for international expansion.

Inspired by our vision of the affordable, reliable, net-zero carbon grid, Mainspring is rapidly expanding within the $816B global electricity equipment market, and we’re hiring the best talent to meet growing customer demand around the globe. We welcome a broad range of backgrounds, experiences, and talents to bring fresh perspectives and ongoing innovation to our customers.

We are looking to build relationships with people who share our values:

Excellence without Ego. We bring expertise and commitment to creating the best customer experience, from sales to deployment and service, just as we apply deep technical rigor to building and delivering world-class products. We strive for excellence and behave as leaders with the humility to acknowledge our challenges, both collectively and as individual contributors.

Proactive Collaboration. The integration and cross-disciplinary nature of Mainspring’s business requires intentionally seeking out others who bring different skills, perspectives, and priorities. Our culture of inclusion and respect extends beyond our team to interactions with our partners and customers.

More information can be found at

Mainspring is looking for Senior Mechanical Design Engineers with a focus on designing sheet metal components and assemblies. In this role, you will be responsible for developing and improving designs, overcoming DFM challenges, managing vendors, procuring and testing parts, and ensuring high-quality execution across all phases of product development. The ideal candidate will have a strong combination of technical expertise and the drive to solve complex problems in a collaborative environment.

• Contribute to brainstorming and technical review sessions to develop solutions that improve performance, cost‑efficiency, and reliability of the Linear Generator.
• Take ownership of the design, analysis, testing, and optimization of structural systems, with attention to cost, safety, and reliability trade‑offs.
• Apply sheet metal and joint design knowledge to support development of complex assemblies with efficient manufacturing processes.
• Perform FEA analyses by breaking down complex loading conditions into solvable problems to inform design improvements.
• Conduct tolerance stack‑up analysis to support robust and manufacturable designs.
• Use CAD tools to create detailed drawings and 3D models, maintaining accuracy in design and documentation.
• Support procurement, fabrication, and testing of parts, contributing to hands‑on validation and iterative development.
• Collaborate closely with manufacturing, NPI, test, and reliability teams to ensure designs meet performance, manufacturability, and quality goals.
• Interface with vendors and suppliers to support quality manufacturing and timely delivery.
• Participate in DFMEA processes to help identify and mitigate potential failure modes.
• Manage tasks and priorities effectively, supporting delivery of key engineering milestones.

• Degree: BS or MS in Mechanical Engineering or a…