Product Design Engineer

LEX Diagnostics Limited; Melbourn; On-site; GBP 60,000 - 80,000; Full time

Job summary

A fast-growing diagnostics company in the UK is seeking a Mechanical Designer to create and refine solutions for next-gen diagnostics platforms. The role requires deep CAD experience, preferably in SolidWorks, and the ability to collaborate effectively with diverse teams. You'll have a direct impact on product development, with benefits that include a competitive salary, medical insurance, and a supportive team environment.

Benefits

Competitive salary

10% employer pension contribution

Private medical insurance

Life insurance

25 days' holiday + bank holidays

Qualifications

• Strong portfolio of product/test rig/jig designs.
• Deep CAD experience, ideally SolidWorks.
• Hands-on prototyping and assembly experience.

Responsibilities

• Design jigs, test rigs, and subsystems.
• Develop full mechanical designs.
• Assemble, iterate, and troubleshoot assemblies.

Skills

CAD design

Prototyping

Collaboration

Tolerance analysis

Electromechanical systems

Tools

SolidWorks

Job description

What you’ll be doing

In short: designing the things that make the thing work.

You’ll be part of a small but mighty mechanical engineering team, working alongside other engineers, scientists, firmware developers, and product managers. Your job is to design the product, and build the jigs, fixtures, and subsystems that bring our platform to life.

This is a hands-on role. You’ll be deep in CAD one day, on the bench troubleshooting an electro-mechanical prototype the next. You’re not expected to be the “blue-sky concept” person, but you’ll work closely with those who are. Your superpower is turning big (and sometimes vague) ideas into robust, elegant designs.

Expect to:

• Design jigs, test rigs, and subsystems to support product development and verification
• Develop full mechanical designs in SolidWorks (this is your second language)
• Specify parts for manufacturability, durability, and performance
• Apply tolerance analysis and dimensioning (ideally using GD&T)
• Assemble, iterate, and troubleshoot mechanical and electro-mechanical assemblies
• Collaborate with cross-functional teams on systems involving thermal, fluidic, and motion control
• Engage in design reviews, test planning, and real-world problem solving

In 2025, you’ll help optimise and refine our existing system. In 2026, you’ll be starting fresh, helping us define and deliver the next-generation platform.

What we’re looking for

You’re not just a good designer, you’re a good collaborator. You know how to talk to scientists, biologists, and less-technical colleagues without making them feel like they’re speaking a different language.

We’d love to hear from you if you have:

• A strong portfolio of product/test rig/jig designs (and the stories behind them)
• Deep CAD experience, ideally SolidWorks, with a focus on real-world, manufacturable solutions
• Knowledge of materials, tolerances, and how to design for robustness and repeatability
• Hands on prototyping and assembly experience (you’re the person who builds the thing you design)
• Familiarity with electromechanical, thermal, or fluidic systems
• Confidence working in a multidisciplinary team with varied skillsets and communication styles
• Experience working alongside “big idea” people, and grounding those ideas in practical design

Bonus points if you’ve worked in ISO13485 environments or helped take a product from lab prototype to scaled manufacture.

LEX Diagnostics is scaling fast, with major investment, an FDA submission in motion, and big plans for 2026. We\'re still small enough for everyone to have a voice, but big enough to do serious engineering. Your work will have a direct impact on our next chapter.

Benefits

Here’s what you’ll get:

• Competitive salary based on experience
• 10% employer pension contribution (+3% from you)
• Private medical insurance
• Life insurance
• 25 days’ holiday + bank holidays
• Autonomy, support, and the right tools for the job
• A collaborative, ego-free team who enjoy solving hard problems together

Want to help shape both the product, and the future of a next-gen diagnostics platform?

Click apply. Or let’s talk. We’re happy to show you what we’re building.