Salary not listedPosted 14m ago
Real job — pulled straight from CommonwealthFusion’s careers page · Verified September 26, 2026 · No reposts.
Job description
CommonwealthFusion is hiring a Senior Mechanical Engineer, Assembly — a full-time, based in Devens, MA role. Apply directly on CommonwealthFusion's careers page below.
Senior Field Mechanical Engineer - Assembly - Second Shift
Team: Assembly
Location: Devens, MA
Commitment: Full-time
Workplace Type: onsite
Salary:
Salary range for this full-time position + equity + benefits. The actual salary will depend on level, location, qualifications, and experience. The range displayed on each job posting reflects new hire salaries for the position across all US locations. Benefits include:
• Competitive compensation with equity
• 13 Company-wide Holidays
• Flexible vacation days
• 10 sick days
• Generous parental leave policy
• Health, dental, and vision insurance
• 401(k) with employer matching
• Professional growth opportunities
• Team-building activities
About Commonwealth Fusion Systems:
Commonwealth Fusion Systems is on a mission to deliver the urgent transition to fusion energy.
Combining decades of research, top talent, and new technologies, we’re designing and building commercially viable fusion power plants. And we're working with policymakers, suppliers, and many others to build the energy industry of the future.
We’re in the best position to make it happen. Since 2018, we’ve raised $4 billion of capital, making us the largest and leading fusion company in the world.
Now we’re looking for more thinkers, doers, builders, and makers to join us. People who’ll bring new perspectives, solve tough problems, and thrive as part of a team.
If that’s you and this role fits, we want to hear from you.
Join the power movement as a Senior Field Mechanical Engineer - Assembly
As the Senior Field Mechanical Engineer on the Assembly Team at CFS, you will be responsible for the management, engineering oversight, and problem-solving of the most complex and unique work-stations of the SPARC assembly process. You will be the central owner and know your part of the assembly process through-and-through, and you help guide the technicians through any issues that arise along the way, coming up with solutions that continue work and assembly moving forward. You will proactively ensure that they have all the tools required for the work, either procuring them off-the-shelf or quickly designing and building small tools and fixtures for use. This also includes the close collaboration with adjacent teams on the Assembly Team, such as creating and incorporating the new process changes with the Assembly Process team, or providing the Metrology team with any assistance or tools needed for the precision alignment of coils and other key structures. This role is on-site at Devens, MA but is a “field” role in the sense that you will be working day-to-day in the central construction hall in the CFS-2 facility where we are building the SPARC Tokamak. At the core, your role is to keep the assembly process moving smoothly in any and all ways, managing the day-to-day changes in strategy or work orders, problem-solving and making tools, and using your engineering skills and knowledge to solve the many complex challenges that arise during the assembly process. You will guide and manage how the giant parts of this multi-million pound “Swiss-watch” come together!
This particular role is scoped to be third shift focused for the duration of the SPARC Tokamak build project.
Hours: 3:00 pm - 1:00 am
Salary + 10% differential
What you'll do:
- Station owner working on night hours with start times ranging from 3p to 7p for five nights a week
- Owner and expert in the assembly sequence of your work-station, with the responsibility to determine and enact acceptable solutions and changes to the sequence that both allow successful completion of the work-station but also fit with the entire SPARC assembly sequence
- Responsible for new first-encounter work scope definition from the large magnet positioning and installs to the precise plasma facing component alignment and adjustment
- Determination and execution of solutions for identified assembly issues that arise, such as fit, method, or component handling problems. Work with the Tokamak System design teams to determine how a part or process step could be modified to work while also meeting functional requirements
- Proactively procure or build all tools, fixtures, or manipulation equipment required for the upcoming parts of the process in your work-station
- Serve as the extreme owner for a process by testing, implementing, and handing off to production technicians for repeated use for any given operation or tool(s)
- Provide design feedback to SPARC sub-system designs with a focus on manufacturing and assembly. Participate in both formal and informal design reviews to ensure what is delivered can be assembled
- Assist in the disposition and resolution of non-conformance issues on parts or the process, then working to incorporate and release red-line changes into an updated assembly sequence
- Support hands on operations during Tokamak Assembly serving a variety of roles in the process
- Work with teammates in a collaborative fashion to receive feedback early and often to ensure all requirements are met. Many SPARC projects involve high loads, vacuum requirements, and complex manipulation requiring the involvement and review of adjacent sub system experts
What we’re looking for:
- Civil, Mechanical, or Aerospace Engineering B.S.
- 7+ years of Mechanical Engineering
- Experience demonstrating project ownership
- 4+ years experience in overseeing an in-progress construction, manufacturing, or assembly/integration process
- 4+ years of experience with CAD software
Bonus points for:
- 3+ years of experience with Siemens NX
-
Lifting operations experience
-
Knowledge of welding
-
Knowledge of piping and tubing construction and joining
-
Experience with highly complex or delicate assemblies
-
Experience with assembly or integration in tightly packaged spaces
-
Experience with fast-paced and dynamic construction, manufacturing, or assembly/integration builds
-
Design of simple yet sizeable alignment and positioning fixtures
-
Heavy component manipulation and welding of large structures
Must-have Requirements:
- Ability to occasionally lift up to 50 lbs
- Perform activities such as typing, standing, stooping, climbing or sitting for extended periods of time
- Required onsite 5 days/week when assembly operations with relevant tools are underway, with possible first or second shift assignment
- Work in a facility that contains industrial hazards including heat, cold, noise, fumes, strong magnets, lead (Pb), high voltage, high current, pressure systems, and cryogenics
At CFS, we excel in fast-paced environments, driven by our values of integrity, execution, impact, and self-critique. As we grow, we’re eager to bring on mission-driven folks who offer diverse perspectives and fresh ways to tackle challenges.
We value diversity deeply and are proud to be an equal opportunity employer by choice. We consider all qualified applicants equally, regardless of race, color, national origin, ancestry, citizenship status, protected veteran status, religion, physical or mental disability, marital status, sex, sexual orientation, gender identity or expression, age, or any other basis protected by law.
This role requires compliance with U.S. laws concerning the export of controlled or protected technologies or information (collectively, “Export Control Laws"). Any offer of employment will be contingent on the need for compliance with such Export Control Laws.
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Frequently asked questions
What skills are required for Senior Mechanical Engineer, Assembly at CommonwealthFusion?
The required skills for Senior Mechanical Engineer, Assembly at CommonwealthFusion include: Mechanical Engineering, Welding, Assembly.
What is the seniority level for Senior Mechanical Engineer, Assembly at CommonwealthFusion?
Senior Mechanical Engineer, Assembly at CommonwealthFusion is a Senior level position.
How do I apply for Senior Mechanical Engineer, Assembly at CommonwealthFusion?
You can view the full description and apply for Senior Mechanical Engineer, Assembly at CommonwealthFusion on EchoJobs: https://echojobs.io/job/commonwealthfusion-senior-field-mechanical-engineer-assembly-second-shift-8kjho.