Sr. Mechanical Design Engineer

Flex•Littleton, MA

2d•Onsite

About The Position

At JetCool, a Flex company, we’re at the forefront of liquid cooling innovation, delivering advanced solutions that empower our partners in AI and high-performance computing. United by a shared purpose, our teams are pushing the limits of what’s possible and tackling complex challenges. A career at JetCool offers the opportunity to make a real impact by helping build smarter, more sustainable data centers. Together, we’re not just advancing technology — we’re redefining cooling standards to create a more sustainable tomorrow. Job Summary To support our extraordinary teams who build great products and contribute to our growth, we’re looking to add a Sr. Mechanical Design Engineer located in Littleton, MA. Reporting to the Mechanical Development Associate Principal Engineer the Sr. Mechanical Design Engineer will take full ownership of converting concepts and SolidWorks CAD models into robust, manufacturable, and production‑ready designs. This role is responsible not just for creating models, but for expertly detailing SolidWorks designs into clear, complete, and executable documentation that enables low‑cost, high‑quality, repeatable manufacturing.

Requirements

8+ years of experience in detailed mechanical design with direct ownership of production‑released hardware.
Expert proficiency in SolidWorks, including advanced part modeling, assemblies, configurations, and drawing creation with manufacturing‑ready detail.
Demonstrated mastery of GD&T, tolerance analysis, and precision detailing, applied intentionally to real manufacturing and assembly constraints.
Extensive experience creating clear, unambiguous engineering drawings for machined parts, sheet metal, weldments, and complex assemblies.
Strong working knowledge of ASME drawing standards and common manufacturing best practices.
Proven experience detailing fabricated and welded structures, including weld definitions, callouts, and fabrication clarity.
Deep understanding of manufacturing processes (machining, sheet metal, welding, precision assembly) and how SolidWorks design decisions affect cost, quality, and yield.
Experience selecting and applying materials, seals, gaskets, and hardware in demanding mechanical systems.
Strong experience developing and maintaining structured BOMs, part numbering schemes, and controlled documentation sets.
Demonstrated ownership mentality—taking responsibility for design quality, manufacturability, cost, and downstream success through production.
Clear communicator who can effectively work with engineers, manufacturing teams, and suppliers to drive issues to closure.

Responsibilities

Take end‑to‑end ownership of detailed mechanical design, from early concepts through fully released, production‑ready SolidWorks models and documentation.
Expertly detail SolidWorks parts and assemblies, converting conceptual designs into fully defined geometry with proper tolerances, fits, interfaces, and manufacturing intent.
Own tolerance stack‑ups, GD&T application, and fit/function strategy, ensuring designs assemble reliably and perform as intended in production.
Produce high‑quality engineering drawings (machined parts, sheet metal, weldments, and assemblies) using ASME Y14 and applicable industry standards, with clarity suitable for external suppliers.
Own weldment modeling and drawings in SolidWorks, including joint design, weld symbols, fabrication notes, and distortion considerations.
Select and specify materials, seals, gaskets, fasteners, and finishes, balancing performance, manufacturability, durability, cost, and supply‑chain constraints.
Build and maintain complete documentation packages, including SolidWorks models, drawings, specifications, and structured BOMs, with accountability for accuracy and completeness.
Define and own BOM structure and product hierarchy, supporting manufacturing, sourcing, configuration control, and lifecycle management.
Lead design reviews with an ownership mindset, proactively identifying tolerance risk, manufacturability issues, assembly challenges, and cost drivers.
Partner closely with manufacturing, quality, and suppliers to resolve build issues, clarify documentation, and continuously improve design robustness and producibility.