Senior Mechanical Design Engineer

Smiths Detection is a global leader in threat detection and screening technologies supporting aviation, ports & borders, defence, and urban security.

With 5 R&D centres, 21 global offices, and 7 manufacturing sites, our 3,000 brilliant minds have spent over 40 years at the frontline, developing solutions that protect society from explosives, prohibited weapons, contraband, toxic chemicals, and narcotics.

Every minute of every day, our technology and people help make the world a safer place.
Learn more about what we do:

Job Description

We are looking for a talented Mechanical Design Engineer to join our Technology function, here in Hemel Hempstead, working at the forefront of innovation in a highly regulated environment.

In this role, you’ll play a key part in designing and developing cutting-edge products—working within multidisciplinary teams to translate complex technical challenges into robust, manufacturable solutions.

This is an exciting opportunity for a creative and hands-on engineer who thrives on delivering high-quality designs from concept through to production.

What You’ll Be Doing

• Develop innovative mechanical design solutions to meet challenging customer and regulatory requirements
• Generate concept designs and collaborate with scientists and engineers on experimental hardware
• Translate technical requirements into practical, cost-effective design solutions
• Lead and contribute to the industrial design process
• Create detailed 3D models using SolidWorks and apply design-for-excellence principles
• Build and test prototypes, including environmental validation (temperature, shock, vibration, ingress)
• Define and execute verification and validation testing
• Produce comprehensive engineering documentation and technical data packs
• Support products throughout their lifecycle, driving continuous improvement
• Work across multi-functional project teams on multiple concurrent projects
• Mentor junior engineers and contribute to ongoing departmental development.

Qualifications

• Must be UK based already and eligible to obtain SC level clearance.
• Degree or HNC in Mechanical Engineering (or equivalent).
• Minimum 5 years’ experience in mechanical design engineering.
• Strong experience designing electronic/scientific equipment packaging for harsh environments.
• Proficiency in 3D CAD tools (SolidWorks preferred).
• Experience with prototyping, testing, and validation.
• Strong communication skills and ability to collaborate across teams.

Knowledge of manufacturing processes including:

• Injection moulding
• Sheet metal design
• Additive manufacturing
• Conventional machining

Desirable Experience:

• Analytical instrument design (e.g. ion mobility spectrometry or mass spectrometry)
• Simulation tools such as COMSOL, MATLAB, or LabVIEW
• Thermal and fluid flow analysis
• Familiarity with military standards
• Understanding of gated engineering design processes
• Exposure to ERP or product lifecycle systems

Additional Information

Join us and we’ll help build your career, with excellent training and opportunities for career growth across the business, both locally and globally. You’ll experience an inclusive environment, with strong leadership and a focus on safety and wellbeing. You’ll also have the flexibility to choose from a wide range of benefits to suit your lifestyle, offering you and your family support from a health and wellbeing, financial and lifestyle perspective.

Join us and work for a world-leader, with the benefits and training to reward your dedication and skills. Be part of a team where we are making the world a safer place.

We believe that different perspectives and backgrounds are what make a company flourish. All qualified applicants will receive equal consideration for employment regardless of color, religion, sex, sexual orientation, gender identity, national origin, economic status, disability, age, or any other legally protected characteristics. We are proud to be an inclusive company with values grounded in equality and ethics, where we celebrate, support, and embrace diversity.

At no time during the hiring process will Smiths Group, nor any of our recruitment partners ever request payment to enable participation – including, but not limited to, interviews or testing. Avoid fraudulent requests by applying jobs directly through our career’s website ( Careers - Smiths Group plc )