Senior Mechanical Engineer

The Role

We are seeking an experienced and motivated Senior Mechanical Engineer to lead the design and development of precision opto-mechanical systems critical to the performance of Flux’s Optical Tensor Processing Units (OTPUs). This role is ideal for an engineer with proven experience in designing stable, high-precision mechanical assemblies for optical systems. You will work closely with cross-functional teams—including optical, electronic, and packaging engineers—to develop and refine mechanical designs that meet demanding performance, thermal, and alignment specifications in a fast-paced R&D environment.

Responsibilities

• Design and develop mechanical assemblies for optical systems, including precision mounts, alignment stages, and thermal enclosures for photonic and electronic components.

• Collaborate with optical engineers to define tolerances and alignment strategies for lasers, detectors, lenses, and free-space or fiber-optic components.

• Develop CAD models and detailed mechanical drawings using tools such as SolidWorks or Siemens NX, ensuring manufacturability and integration into system-level enclosures.

• Lead the thermal and structural analysis of mechanical components and assemblies to ensure system reliability under various operating conditions (vibration, shock, temperature).

• Evaluate materials and surface finishes for thermal management, mechanical stability, and optical compatibility.

• Interface with vendors and manufacturing teams to support prototype fabrication, DFM (Design for Manufacturability), and design iterations.

• Develop jigs, fixtures, and alignment tools to streamline optical assembly and validation processes.

• Support environmental and reliability testing, including thermal cycling, vibration, and mechanical stress validation.

• Create and maintain comprehensive documentation, including BOMs, tolerance analyses, and assembly instructions.

• Collaborate across disciplines to ensure that mechanical design supports electrical, optical, and thermal performance goals in compact, integrated hardware.

Skills & Experience

• 7+ years of experience in mechanical design, with a strong focus on opto-mechanical systems and high-precision assemblies.

• Demonstrated experience designing for optical alignment, stability, and environmental robustness in photonic or laser-based systems.

• Proficiency in 3D CAD tools (e.g., SolidWorks, Creo, or NX) and experience generating detailed manufacturing drawings with GD&T.

• Strong understanding of materials, tolerances, thermal properties, and structural mechanics relevant to optical systems.

• Experience working with interdisciplinary teams in the design and integration of complex electro-optical systems.

• Proven track record of transitioning designs from concept through to manufacture, including prototype testing and iteration.

• Bachelor’s degree in Mechanical Engineering or a related field; Master’s or PhD preferred.

• Ability to work independently in a fast-paced, collaborative environment and drive results across cross-functional teams.

Compensation & Benefits

• £95,000 – £132,000 annual salary, depending on experience, skills, and location.

• Competitive stock options, you’re not just part of the journey, you will own a piece of it.

• Work from our HQ in King’s Cross, right in the middle of London’s buzzing AI scene.

• Live within 45 minutes of the office? Perfect. Live within 20 minutes? We’ll add an extra location bonus (£24K) to your salary.

• We offer visa sponsorship and full relocation support (UK and abroad), through a dedicated third-party provider who are on hand to make your move to London as seamless as possible.

• Full BUPA healthcare and dental cover, medical history disregarded.

• High-spec tech for everyone - M4 Macs as standard, M4 Pros for Engineers.

• Sony noise-cancelling headphones and ergonomic setups to keep you comfortable and focused.

• Personal company card to spend on tools that help you do your job - like ChatGPT Pro or anything else that boosts your workflow.

• Healthy, chef-cooked dinners in the office every night, with something for every diet and tastebud.

• Monthly off-site team socials.

• 25 days of paid holiday, plus all the UK bank holidays.

• Access to our in-house 3D printer for personal or work projects.

• Cycle2work scheme.

• Need a caffeine fix? We’ve got you covered with a tab at our favourite local coffee shop.

• We offer a pension plan and salary sacrifice options.

We do not accept unsolicited CVs from recruitment agencies, will not be liable for any fees, and prohibit unauthorised use of our company name in recruitment activities.

We’re building fast and that includes our benefits. More exciting additions are coming soon.

If you are passionate about pushing the boundaries of what's possible in AI and thrive in a high-energy, fast-paced environment, we want to hear from you.