Senior Mechanical Engineer

Exthymic•San Diego, CA

13d

About The Position

We are scientists, engineers, and operators who have spent our careers inside cell therapy manufacturing. We have built the platforms, scaled production, and watched these treatments fail to reach the patients who need them. We are building the technology to close that gap. If this is work you want to do, read on. You are a hands-on Senior Mechanical Engineer who turns requirements into working hardware. You move fluidly between CAD and the bench, and you know the difference between a prototype that proves a concept and a design that's ready to build. You take pride in parts that are not just functional but manufacturable and serviceable, and you are comfortable owning the detailed design of components and subsystems while collaborating with fluidics, software, and biology teams to get the whole instrument working. You have instrument and consumables design experience and a track record of translating high-level product and process requirements into prototypes across stages of development, from breadboard through functional verification.

Requirements

Bachelor's or advanced degree in mechanical engineering or other relevant disciplines.
5–7 years of relevant mechanical design experience, including instrument or hardware product development; experience with biological or chemical systems in instrumentation is a strong plus.
Direct experience with common fabrication techniques (CNC, sheet metal, molding, forming, stamping, die-cut, 3D printing, etc.).
Proficiency with enterprise CAD software (e.g., Solidworks, NX, Creo, Onshape, or Fusion360).
Passion for rapid prototyping and iteration, quickly turning concepts into testable hardware and refining across build-test-learn cycles.
Familiarity with design for manufacturing and assembly, including tolerance analysis and cost optimization.
Experience authoring and executing structured test protocols, capturing data, and writing engineering reports.
High tolerance for executing design work in an environment where requirements are still being defined alongside the biology.
Hands-on experience with laboratory work and collaborating with bench scientists.

Nice To Haves

Track record of working in an interdisciplinary R&D / early product development setting.
Experience with regulated product development under 21 CFR Part 820 and ISO 13485, including contributing to design history files.
Familiarity with cell therapy manufacturing workflows, bioprocessing equipment, or related biological manufacturing.
Experience designing disposable consumables, including cartridge interfaces and single-use flow paths.
Experience using simulation tools (ANSYS, COMSOL, SolidWorks Simulation) for thermal, structural, or fluid analysis.
Software-literate and open-source-minded; comfortable scripting to automate design and analysis tasks.
Experience evaluating and working with job-specific AI tools, including using AI/LLM tools to accelerate the mechanical workflow generative and CAD-assisted design exploration, DFM and tolerance analysis, documentation and BOM generation

Responsibilities

Translate requirements into mechanical designs—Take product and process requirements and turn them into detailed component and subsystem designs, including material and component selection, make-versus-buy calls, and tolerancing. Work within the broader system architecture set in partnership with systems and senior engineering.
Build, assemble, and test prototype hardware—Hands-on fabrication and bring-up across mechanical, fluidic, and optical subsystems, from first article through functional verification. Drive failures to root cause and iterate quickly.
Design for manufacturability and assembly—Apply DFM and tolerance analysis, develop BOMs, and refine designs for cost, reliability, and serviceability as they mature toward production.
Coordinate with external fabrication and assembly vendors—Work with vendors to get parts made and assembled, managing quality, schedule, and cost on the components you own.
Collaborate across fluidics, software, and biology teams—Work directly with cross-functional partners to understand how mechanical decisions affect process performance and fold those findings back into design changes.
Contribute to design control and documentation—Maintain engineering drawings, BOMs, and design rationale as living artifacts.