Senior Mechanical Design Engineer - Mechanical Integration (Menlo Park)

Company Overview

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.

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

Pragmatic Optimism. Building a new category of world-class power generation requires the optimism of ambition and creativity, balanced with practicality to solve problems efficiently. The challenges that arise are opportunities for growth.

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 Mainsprings 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

Job Overview

We are seeking a Mechanical Design Engineer with strong fundamentals, creativity, and attention to detail to join our Mechanical Integration Team. This role focuses on designing and testing components and assemblies for high-performance generators in a collaborative and fast-paced environment. The ideal candidate will bring a solid background in mechanical design, manufacturing methods, structured engineering processes, mechatronics integration experience, and data analysis techniques.

• Design, analyze, and develop components and assemblies for integrating generator hardware subsystems into the larger product assemblies. Attention to performance, reliability, and manufacturability
• Own designs from initial concept through prototype build, testing, and release to production
• Create 3D CAD models and 2D drawings with appropriate tolerancing and GD&T for manufacturing and inspection
• Support root cause analysis and resolution of mechanical issues from test and fielded systems
• Interface with cross-functional teams including Electrical Engineering, Manufacturing, Test, and Supply Chain
• Contribute to and participate in structured design reviews and release processes
• Develop and manage BOMs, specifications, and documentation within PLM systems
• Select materials and surface treatments appropriate for strength, corrosion resistance, and environmental conditions
• Apply knowledge of mechanical engineering fundamentals including stress, thermal analysis, vibration, and fatigue
• Experience in part and assembly design for manufacturing (DFM), including close collaboration with suppliers and manufacturing partners

• Degree in Mechanical Engineering or a similar engineering field from an accredited institution. Experience and degree will determine level, but minimum requirements are:BS + 8 years of relevant working experience or MS + 6 years of relevant working experience
• Suitable experience for level doing analysis of industrial equipment components. Beneficial if there is past experience developing engine integration subsystems for industrial equipment. Specifically, experience engineering designs that involve elevated temperatures, mounting and isolation systems,intake or exhaust systems, or rotating equipment
• Experience with hands-on prototyping, designing test benches, test fixtures, data acquisition and basic test data reduction
• Good understanding of metal castings, welding/fabrication, sheet metal, stamping, structural FEA, datum selection, tolerance stackup analysis, hardware component selection, and finishing processes with the ability to identify and resolve design for manufacturability issues. Deep understanding at Staff level
• Experience performing technical reviews for drawing and CAD design release packages for completeness, assembly packaging checks, and design intent
• Fluent in SolidWorks or comparable CAD package. Experience with using PDM or a similar CAD version control system is preferred
• Interest in developing creative and cost effective solutions to enable the deployment of zero carbon energy technology at large scale

$126,000 - $148,000 a year

This position is onsite at our Menlo Park HQ. The salary will be adjusted to reflect local market conditions based on employee location as well as the experience of the employee. Along with the base salary, Mainspring offers pre-IPO stock options + benefits.

Does your experience not meet all of our posted requirements? Studies have shown that some people are less likely to apply to positions unless they meet every listed requirement. 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. We generally do not negotiate on salary once we have made an offer. The level of pay within the range will depend on a variety of job-related factors that may include location, relevant prior experience and/or education, or particular skills and expertise. 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.