Senior Mechanical Design Engineer - Metal Structures

About Mainspring

Mainspring Energy manufactures and delivers fuel-flexible, low-emissions local power solutions that rapidly add new capacity and deliver reliable, affordable, and sustainable electric power. The company began commercial shipments of its Mainspring Linear Generators in 2020 and today has hundreds of megawatts in advanced development and field operations for leading Fortune 500 companies, data centers, and utilities. Mainspring also partners with global energy leaders including AEP, Next Era Energy Resources, Schneider Electric, and more.

Core values that ground our work, guide our decisions, and connect us together:

• Pragmatic Optimism
• Excellence without Ego
• Proactive Collaboration

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 similar engineering field from an accredited institution. Experience and degree will determine the level, with the following minimum requirements:
  Senior: BS + 6 years or MS + 5 years
• Strong knowledge of sheet metal design, manufacturing processes, fastener selection, joint design, coatings, and assembly practices.
• Experience designing for durability under cyclic and thermal loading, with an awareness of vibration and acoustic challenges.
• Proven track record contributing to complex projects by helping define requirements, evaluating technical trade-offs, identifying risks, and supporting key decisions to meet functional and performance goals.
• Detail-oriented, with experience generating and reviewing drawings, bills of materials, tolerance stack-ups, work instructions, and test documentation.
• Proficient in Solid Works and PDM (or similar CAD version control systems), with experience using FEA and CFD tools such as Solid Works Flow Simulation or Ansys.
• Familiarity with forming analysis tools to catch DFM challenges early is a plus.
• Comfortable working hands‑on with prototyping, testing, and failure analysis of structural components.
• Experience working cross functionally with manufacturing, supply chain, test and reliability teams.
• Self-motivated and capable of delivering high-quality design work in a fast-paced environment. Experience across the full product development cycle—from concept through manufacturing support—is valued.
• Enthusiastic about supporting and sharing knowledge with peers and junior engineers.
• Passion for creating innovative…