Smiths Detection is a global leader in threat detection and screening technologies, providing advanced solutions to protect people and infrastructure by helping prevent the illegal trafficking of drugs, weapons, harmful chemicals and explosives. Our products are deployed in highly regulated environments, including Aviation Security, Customs & Border Control, Defense & Military, Law Enforcement & First Responders, Critical Infrastructure Protection, and Ports & Cargo Screening. This role will be at our R&D site in Hemel Hempstead, due to sensitive nature of the products you will be working on, you will have to undergo UK SC Level Clearance, we are unable to sponsor. The Role We are seeking an experienced Mechanical Design Engineer to join our dynamic team. This role is strongly preferred for professionals who have worked in the design and development of mechanical systems for security, defense, or highly regulated industries. You will play a key role in developing robust, high-performance solutions that meet stringent industry and regulatory standards. Key Responsibilities Design and develop mechanical components and assemblies for detection and screening equipment used in security applications. Work closely with multi-disciplinary teams (electronics, software, systems engineering) to integrate mechanical designs into complex products. Conduct 3D CAD modelling and produce detailed engineering drawings (SolidWorks preferred). Perform mechanical analysis (stress, thermal, vibration, and fatigue) to ensure structural integrity and reliability in demanding operational environments. Support prototyping, testing, and validation of new designs in compliance with industry-specific standards. Ensure compliance with regulatory and certification requirements applicable to aviation security, border control, defense, and critical infrastructure. Work with manufacturing teams and suppliers to optimize design for production, cost efficiency, and quality. Participate in design reviews, FMEA, and risk assessments to enhance reliability and safety. Key Skills & Experience Proven experience as a Mechanical Design Engineer in a manufacturing environment supplying to aviation security, defense, law enforcement, or other regulated sectors. Proficiency in 3D CAD software (SolidWorks preferred) and engineering drawing creation. Strong knowledge of mechanical design principles, materials selection, and manufacturing processes. Experience with DFM (Design for Manufacturability) and DFA (Design for Assembly) methodologies. Familiarity with standards and regulations in security-related industries. Experience with thermal management, shock, and vibration considerations for ruggedized equipment is highly desirable. Knowledge of Finite Element Analysis (FEA) tools for mechanical validation. Ability to work in a cross-functional team environment and effectively communicate technical concepts. Why Join Us? Work on cutting-edge technology that protects people and infrastructure worldwide. Be part of a highly skilled and innovative engineering team. Competitive salary and benefits package. Opportunities for career growth and professional development. A collaborative, inclusive, and mission-driven work environment. Diversity and Inclusion: We believe that different perspectives and backgrounds are what make a company flourish. All qualified applicants will receive equal consideration for employment regardless of race, 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. We have several employee-led Employee Resources Groups (womenwork, Black Employees Network, Veterans, Pride Network) providing support, enhancing career development, and contributing to personal development in the work environment and beyond. At no time during the hiring process will Smiths Detection, 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 ( www.smithsdetection.com/careers )or LinkedIn.