Mechanical Product Engineer

About Lumilens At Lumilens we are building the critical photonics infrastructure that powers tomorrow’s AI supercomputing. From chip-to-chip optical interconnects to scalable photonic engines, Lumilens is unlocking a new era of computing - faster, cooler, and massively more efficient. We’re a well-funded startup backed by Mayfield and led by veterans who’ve built and scaled some of the most transformative technologies in the industry. At Lumilens, we’re developing high-speed photonics products purpose-built to power the future of AI infrastructure and high-performance computing. This isn’t incremental innovation, it’s a ground-floor opportunity to rethink the optical layer from the silicon up. You’ll work alongside a team of world-class engineers solving some of the hardest challenges in scaling optical systems. If you're looking for mission, momentum, and the chance to make an outsized impact, jump on the rocket ship. We’re just getting started. Position Overview We are seeking a hands-on Mechanical Product Engineer to serve as the primary mechanical engineering interface between Lumilens’ hardware design teams and our worldwide contract manufacturers (CM) and supplier network. In this role you are the mechanical DRI (Directly Responsible Individual) for the manufacturing launch, sustaining, and continuous improvement of Lumilens’ next-generation optical and AI infrastructure. You will own the full arc from early development engagements, through NPI build planning, through volume production release—driving quality, cost, yield, and schedule with the CMs and key suppliers while partnering upstream with Optical, Hardware, and Mechanical Design Engineering teams. This role focuses on precision mechanical design, product packaging, structural design, thermal/mechanical considerations, and system integration—turning loosely defined requirements into robust, manufacturable hardware. This position is ideal for an engineer who combines deep mechanical product knowledge with a passion for manufacturing process excellence, supplier development, and cross-functional execution at a global scale. And for someone who enjoys building, debugging, and iterating quickly while contributing to mechanical architecture, detail design, tolerance control, and design-for-manufacturing decisions that impact performance, automation, reliability, cost, and scalability. Key Responsibilities - Proto / Engineering Validation Test - Build readiness, BOM validation, mechanical fit checks, first-article inspection at CM. - Design Validation Test - DFM/DFA reviews, tolerance audit, tooling buyoff, GD&T deviations, PFMEA launch. - Process Validation Test - Process capability studies (Cpk), yield ramp, packaging qualification, and cosmetic defect standards. - Mass Production / Sustaining - ECO execution, supplier change management, cost reduction, long-term supply continuity. - Failure Analysis - Drive root‑cause analysis for prototype, production, and field‑reported mechanical issues, delivering containment actions and long‑term corrective solutions - Collaboration - Work closely with product owners, optics, test, electronics, and manufacturing teams to resolve technical tradeoffs, maintain execution timelines, and ramp to high volume production. - Nice to have – Design manufacturing tools, jigs, and fixtures. Work directly with fabrication vendors and suppliers to communicate requirements, validate prototypes, and prove-in tools, jigs, and fixtures for production. What You Will Do - Own end-to-end mechanical NPI execution at CMs and Key Suppliers/Partners from proto builds through mass production release and yield stabilization. - Collaborate in material selections, interfaces, and finishes suitable for precision, optical, ESD‑sensitive, and clean manufacturing environments - Lead mechanical DFM/DFA reviews on housing, sheet metal, die-cast, injection-molded, and extruded components — translating design intent into manufacturable specifications. - Ensure clear