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Senior Field Mechanical Engineer Assembly Second Shift

Commonwealth Fusion Systems

Job Location:

Devens, MA - USA

Yearly Salary: USD 110000 - 185000

Posted: 29 September 2026 (8 days ago)

Application Deadline: 27 December 2026

Vacancies: 1 Vacancy

Job Summary

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 were designing and building commercially viable fusion power plants. And were working with policymakers suppliers and many others to build the energy industry of the future.

Were in the best position to make it happen. Since 2018 weve raised $4 billion of capital making us the largest and leading fusion company in the world.

Now were looking for more thinkers doers builders and makers to join us. People wholl bring new perspectives solve tough problems and thrive as part of a team.

If thats 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 youll 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 were 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

$110000 - $185000 a year

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

At CFS we excel in fast-paced environments driven by our values of integrity execution impact and self-critique. As we grow were 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.

Required Experience:

Senior IC

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