Mechanical Engineer Jobs at Mainspring Energy with Visa Sponsorship
Mechanical Engineer jobs at Mainspring Energy involve developing and manufacturing linear generator technology, with visa sponsorship available across multiple categories. If you're on a work visa or transitioning from OPT, Mainspring treats engineering roles as a core part of its sponsorship pipeline.
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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:
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 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.
Senior Staff Mechanical Engineer – Structures & Alignment
Mainspring’s Linear Generator is fundamentally different from a traditional engine. Instead of rotary motion and a crankshaft, our system converts linear oscillation directly into electricity. A low-temperature, flameless reaction accelerates pistons and its translator shaft wrapped with permanent magnets through stator coils. Air-spring chambers reverse the motion — generating power with high efficiency and ultra-low emissions.
Critically, the translator shaft and pistons float on precision air bearings, riding on a thin film of pressurized air. This minimizes friction and wear — but it also removes rigid mechanical constraints. The translator must remain precisely aligned within tight tolerances across the full cylinder length while traveling at resonance under dynamic loads.
This architecture is elegant — and mechanically unforgiving.
Core Responsibilities
- Lead structural design and alignment strategy for alignment-critical components
- Design and validate bolted joints under cyclic and thermal loading
- Develop GD&T and tolerance stack strategies across subsystem interfaces
- Own 3D CAD (SolidWorks) and structural FEA (ANSYS or equivalent)
- Model structural behavior under vibration and thermal gradients
- Plan and execute durability testing and structured root cause investigations
- Translate test and field data into improved design standards
- Partner with Electrical, Controls, and Manufacturing teams to ensure scalable robustness
Qualifications
- Degree in Mechanical Engineering or a similar engineering field from an accredited institution. Experience and degree will determine level, but minimum requirements are: BS + 12 years experience or MS + 10 years experience
- Delivered products as a technical lead through 3+ full design lifecycles from concept to manufacturing support, preferably with product in high vibration environments with large cyclic loading
- Expertise in bolted joints, thermal impact on structures, design and analysis for severe vibration environments a big plus
- Fluent in SolidWorks or comparable CAD package. Experience with using PDM or a similar CAD version control system is preferred
- Hands-on mechanical prototyping, assembly, testing skills, and experience with mechanical engineering analysis tools (FEA, CFD, thermal analysis, tolerance stack-ups)
- Deep understanding and knowledge of mechanical design principles, materials, manufacturing processes (sheet metal, welding, casting), and ability to identify and resolve design for manufacturability issues
- 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
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 don’t meet all posted requirements for a particular role, we’d 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.
We may use artificial intelligence (AI) tools to support parts of the hiring process, such as reviewing applications, analyzing resumes, or assessing responses. These tools assist our recruitment team but do not replace human judgment. Final hiring decisions are ultimately made by humans. If you would like more information about how your data is processed, please contact us.
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:
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 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.
Senior Staff Mechanical Engineer – Structures & Alignment
Mainspring’s Linear Generator is fundamentally different from a traditional engine. Instead of rotary motion and a crankshaft, our system converts linear oscillation directly into electricity. A low-temperature, flameless reaction accelerates pistons and its translator shaft wrapped with permanent magnets through stator coils. Air-spring chambers reverse the motion — generating power with high efficiency and ultra-low emissions.
Critically, the translator shaft and pistons float on precision air bearings, riding on a thin film of pressurized air. This minimizes friction and wear — but it also removes rigid mechanical constraints. The translator must remain precisely aligned within tight tolerances across the full cylinder length while traveling at resonance under dynamic loads.
This architecture is elegant — and mechanically unforgiving.
Core Responsibilities
- Lead structural design and alignment strategy for alignment-critical components
- Design and validate bolted joints under cyclic and thermal loading
- Develop GD&T and tolerance stack strategies across subsystem interfaces
- Own 3D CAD (SolidWorks) and structural FEA (ANSYS or equivalent)
- Model structural behavior under vibration and thermal gradients
- Plan and execute durability testing and structured root cause investigations
- Translate test and field data into improved design standards
- Partner with Electrical, Controls, and Manufacturing teams to ensure scalable robustness
Qualifications
- Degree in Mechanical Engineering or a similar engineering field from an accredited institution. Experience and degree will determine level, but minimum requirements are: BS + 12 years experience or MS + 10 years experience
- Delivered products as a technical lead through 3+ full design lifecycles from concept to manufacturing support, preferably with product in high vibration environments with large cyclic loading
- Expertise in bolted joints, thermal impact on structures, design and analysis for severe vibration environments a big plus
- Fluent in SolidWorks or comparable CAD package. Experience with using PDM or a similar CAD version control system is preferred
- Hands-on mechanical prototyping, assembly, testing skills, and experience with mechanical engineering analysis tools (FEA, CFD, thermal analysis, tolerance stack-ups)
- Deep understanding and knowledge of mechanical design principles, materials, manufacturing processes (sheet metal, welding, casting), and ability to identify and resolve design for manufacturability issues
- 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
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 don’t meet all posted requirements for a particular role, we’d 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.
We may use artificial intelligence (AI) tools to support parts of the hiring process, such as reviewing applications, analyzing resumes, or assessing responses. These tools assist our recruitment team but do not replace human judgment. Final hiring decisions are ultimately made by humans. If you would like more information about how your data is processed, please contact us.
Tips for Finding Mechanical Engineer Jobs at Mainspring Energy
Tailor your resume to linear generator work
Mainspring builds combustion-based linear generators, so frame your mechanical experience around thermodynamics, combustion systems, or precision manufacturing. Generic mechanical resumes get filtered out early. Highlight tolerances, materials selection, or production-scale hardware development.
Confirm your visa category fits the role
Mainspring sponsors H-1B, E-3, TN, and F-1 OPT for Mechanical Engineers, but not every category fits every situation. Verify your degree field aligns with the specialty occupation definition USCIS requires before you apply.
Time OPT applications around Mainspring's hiring cycles
If you're on F-1 OPT, start your application at least three months before your authorization expires. Mainspring's manufacturing roles often require onboarding ramp time, and USCIS STEM OPT extension processing adds another variable to your timeline.
Use Migrate Mate to find open Mechanical Engineer roles
Mainspring posts Mechanical Engineer openings across different engineering specializations. Use Migrate Mate to filter specifically for Mainspring roles that match your visa type so you're targeting positions the company is actively sponsoring.
Ask about LCA filing during the offer stage
Before signing an offer, confirm your employer will file the Labor Condition Application with DOL promptly. LCA certification is a prerequisite for H-1B and E-3 petitions, and delays at this stage can push your start date beyond your authorized period.
Prepare PERM-relevant documentation early for Green Card pathways
If you're targeting long-term sponsorship, organize transcripts, foreign credential evaluations, and employment verification records now. PERM filings require DOL to audit your qualifications against the job description, and gaps in documentation create costly delays.
Frequently Asked Questions
Does Mainspring Energy sponsor H-1B visas for Mechanical Engineers?
Yes, Mainspring Energy sponsors H-1B visas for Mechanical Engineer roles. The company has a consistent track record of filing H-1B petitions for engineering positions, which reflects how central technical talent is to its manufacturing operations. You'll want to confirm the specific role qualifies as a specialty occupation under USCIS criteria, which generally requires a bachelor's degree or higher in a directly related engineering field.
How do I apply for Mechanical Engineer jobs at Mainspring Energy?
Applications go through Mainspring Energy's careers page, where roles are listed by engineering function. Migrate Mate also aggregates Mainspring's open Mechanical Engineer positions and filters them by visa type, which makes it easier to identify which roles align with your sponsorship situation before you apply. Tailor your application to Mainspring's core focus on linear generator hardware and manufacturing scale-up.
Which visa types does Mainspring Energy commonly use for Mechanical Engineers?
Mainspring Energy sponsors H-1B, E-3 visa, TN visa, F-1 OPT, and EB-2 or EB-3 Green Card pathways for Mechanical Engineers. H-1B and E-3 visa are the most common nonimmigrant routes for engineering hires. Australian nationals can pursue the E-3 without entering the H-1B lottery. Canadian and Mexican nationals in qualifying engineering roles may qualify under TN visa. Green Card sponsorship typically follows after an initial nonimmigrant visa period.
What qualifications does Mainspring Energy expect for Mechanical Engineer roles?
Most Mechanical Engineer postings at Mainspring require a bachelor's degree in mechanical engineering or a closely related field. Roles focused on hardware development and manufacturing often favor candidates with hands-on experience in combustion systems, electromechanical assemblies, or precision machining. For USCIS specialty occupation purposes, your degree field needs to directly correspond to the duties of the specific role you're applying for.
How do I think about the timeline for visa sponsorship at Mainspring Energy?
The timeline depends heavily on your visa category. H-1B petitions are cap-subject and filed once per year, with an October 1 start date, so planning 9 to 12 months ahead matters. E-3 and TN visas can be processed at a consulate with significantly shorter timelines. If you're on OPT, confirm your authorization period gives you enough runway for USCIS to process a change of status petition before your current work authorization expires.