Senior Mechanical Design Engineer - Hybrid in Chelmsford, Essex

Job Title: Senior Mechanical Design Engineer - Thermal Location: Colchester Salary: £60,000 to £70,000 Employment Type: Permanent Working Arrangements: Hybrid working We're supporting a long‑established technology company in Colchester as they continue to expand their engineering capability. They design and manufacture high‑performance electronic systems for defence, aerospace and industrial environments, and due to a strong order book, they're looking to add a Senior Thermal Mechanical Engineer to the team. This is a hands‑on, end‑to‑end role where you'll own thermal performance across complex electromechanical products - from requirements review through to prototype build, test and production support. Creating initial conceptual mechanical designs. - Running detailed structural and thermal analysis (SolidWorks + Flow Simulation preferred). - Presenting work at preliminary and critical design reviews. - Managing projects independently while collaborating with PMs, hardware, software and manufacturing teams. - Investigating production issues, quality problems and root causes under time pressure. - Building, testing and debugging prototypes in the lab. - Designing jigs, fixtures and producing assembly drawings with correct GD&T. - Supporting new product introduction and exploring new thermal technologies (heat pipes, vapour chambers, advanced TIMs). What you'll bring - Strong understanding of thermal principles in electronics. - Proven experience with SolidWorks - Ability to work dynamically, independently and think creatively. - Comfortable engaging with suppliers, project managers and cross‑functional teams. - This role requires the successful candidate to pass BPSS screening and meet the eligibility criteria for Security Check (SC) clearance.