Manufacturing / Mechanical Engineering

Senior Mechanical Engineer - Cylinder Design Mainspring Energy is revolutionizing power generation with the worlds most flexible and adaptable onsite power generator, 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 technology with near-zero NOx emissions. Backed by top-tier investors such as Khosla Ventures, Bill Gates, American Electric Power, and Lightrock, Mainspring designs, manufactures and delivers its products to customers across the U.S. today, and were 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 were 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. Building a new category of world-class power generation requires the optimism of ambition and creativity, balanced with practicality to solve problems efficiently. 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. Our culture of inclusion and respect extends beyond our team to interactions with our partners and customers. Lead essential development efforts for the reaction cylinder component, including design, 3D CAD modeling (Solidworks), engineering analysis (FEA/CFD tools like ANSYS), testing, root cause investigation, and comprehensive documentation. # Collaborate with cross-functional teams (Electrical Engineering, Controls, Manufacturing, Suppliers) to ensure seamless subsystem integration, performance, and new product introduction (DFM/DFA, work instructions, tooling/fixtures). # Plan and execute rigorous verification and validation testing to ensure designs meet all requirements (functional, durability, safety, reliability). # Provide technical guidance to junior engineers and technicians, and contribute to the continuous improvement of engineering processes, tools, standards, and best practices. # Stay current on advancements in mechanical engineering relevant to power generation, and identify opportunities to reduce cost, improve performance, and increase reliability as Mainspring scales its technology. # Uphold and further Mainspring's mission to create clean, affordable, and reliable power generators that accelerate the world's transition to a sustainable energy future. Bachelor's or Master's degree in Mechanical Engineering or similar field. #5+ years as a professional mechanical design engineer. # Delivered products as a technical lead through 2+ full design lifecycles from concept to manufacturing support, preferably in industrial equipment, power generation, or electromechanical machines. # Proficiency in 3D CAD modeling (Solidworks preferred), engineering drawing creation (GD&T), and experience with PDM or similar CAD version control system. # Knowledge of mechanical design principles, materials, manufacturing processes (sheet metal, welding, casting), and ability to identify and resolve design for manufacturability issues. # Hands-on mechanical prototyping, assembly, testing skills, and experience with mechanical engineering analysis tools (FEA, CFD, thermal analysis, tolerance stack-ups). # Expertise in thermal systems, generator combustion systems or design and analysis for severe vibration environments a big plus. Excellent problem-solving, creative thinking, communication, and collaboration skills for effective cross-functional teamwork. # Ability to work independently, manage multiple projects in a fast-paced environment, and demonstrate leadership and mentoring abilities. # Passion for clean energy and commitment to creating a more sustainable world. The Bay Area salary for this role is $126k-$148k base + pre-IPO stock options + benefits. This position is on-site in Menlo Park, CA. At Mainspring, we are committed to building a diverse, inclusive, flexible, and collaborative environment, so if you want to help us transition the world to clean and affordable electricity, and dont meet all posted requirements for a particular role, wed still love to hear from you. Mainspring can sometimes be flexible enough to shift responsibilities for the right person, or otherwise identify open or upcoming roles that may better fit your professional background. In more traditional words, Mainspring Energy, Inc is an Equal Opportunity Employer. All qualified applicants will receive consideration for employment without regard to race, color, religion, sex, sexual orientation, gender identity, national origin, or protected veteran status and will not be discriminated against on the basis of disability. This compensation and benefits information is based on Mainspring Energy's estimate as of the date of publication and may be modified in the future. New hires joining the company tend to be paid within the starting base pay range noted above, with opportunities to increase pay over time based on development of additional skills, competencies, and company-specific knowledge. #