Principal Mechanical Engineer - Vacuum & Thermal R&D Systems

Commonwealth Fusion Systems; Milpitas (CA); On-site; USD 180,000 - 240,000; Full time

Benefits offered by this job

Equity

Health insurance

401(k) with employer matching

13 Company-wide holidays

Flexible vacation days

Generous parental leave

Job summary

Commonwealth Fusion Systems is seeking a Principal Mechanical Engineer to lead end-to-end design and integration of advanced thermal vacuum equipment for next-generation R&D machinery. The role emphasizes technical leadership, architecture innovation, and a strong background in high-temperature and vacuum environments.

You will mentor teams, drive projects from concept to testing, and collaborate with scientists, vacuum specialists, and electrical engineers to ensure high-performance hardware

Qualifications

• Master's degree in Mechanical Engineering or related field (or equivalent industrial experience).
• 15+ years of experience designing and implementing complex R&D systems or semiconductor manufacturing equipment.
• Proven capability in high-temperature structural design and complex thermal management within vacuum environments.
• Deep understanding of vacuum architecture, including material outgassing, seal integrity, and pump-down optimization.
• Proficiency with 3D modeling and FEA/thermal simulation tools (SolidWorks, NX, COMSOL, ANSYS).
• Hands-on capability bridging design and shop floor, including machining, prototyping, and hardware troubleshooting.
• Experience selecting and qualifying global vendors for specialized components or sub-systems.
• Ability to lead effectively in direct and matrixed organizations.

Responsibilities

• Lead design, integration, and validation of advanced R&D processing equipment.
• Define system-level requirements and innovative concepts linked to mechanical precision and product quality.
• Standardize engineering workflows and best practices aligned with semiconductor standards.
• Lead design reviews focusing on manufacturability (DFx) and best practices.
• Collaborate with scientists, vacuum specialists, and electrical engineers to maintain critical interfaces.
• Report milestones to stakeholders and ensure on-time, in-spec delivery.
• Mentor engineering staff on delivery, discipline, and professional growth.
• Drive projects from concept through assembly, testing, and implementation.

Skills

System design

Cross-functional leadership

Agile/adaptability

Vacuum systems

3D modeling

FEA/thermal analysis

Vendor management

Leadership

Education

Master's degree in Mechanical Engineering

Tools

SolidWorks

NX

COMSOL

ANSYS

Job description

Commonwealth Fusion Systems is seeking a Principal Mechanical Engineer to lead end-to-end design and integration of advanced thermal vacuum equipment for next-generation R&D machinery. The role emphasizes technical leadership, architecture innovation, and a strong background in high-temperature and vacuum environments.

You will mentor teams, drive projects from concept to testing, and collaborate with scientists, vacuum specialists, and electrical engineers to ensure high-performance hardware