Demo

Principal Mechanical Engineer

Exthymic
San Diego, CA Full Time
POSTED ON 5/22/2026
AVAILABLE BEFORE 7/22/2026

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.

About You

You are an experienced mechanical engineer who has taken hardware products from concept to launch. You know the difference between a prototype that proves a concept and one that's ready to build at scale. You know when to 3D print and when to specify injection-molded parts, and you take pride in designs that are not just functional, but manufacturable and serviceable. You thrive at the intersection of disciplines, working fluidly with fluidics, software, and biology teams, and are eager to contribute to a mission-driven team focused on democratizing life-saving therapies

You have relevant instrument and consumables design experience with a proven track record of translating high-level product and process requirements into working prototypes at various stages of development, from unit-test breadboards all the way through to product launch.

  • Own the mechanical design of our next generation system - from component selection and make-vs-buy decisions through system-level performance testing. This will require working closely with systems, bioware, informatics, and fluidics teams, with the agency to recruit or contract support as needed.
  • Build, assemble, and test prototype hardware - Hands-on fabrication and bring-up across mechanical, fluidic, and optical subsystems, from first-article through functional verification. 
  • Manage relationships with external fabrication and assembly vendors - Own fabrication and assembly vendor relationships, holding the line on quality, schedule, and cost.
  • Lead design transfer to manufacturing - Drive transfer to pilot production, including process validation and documentation.
  • Partner with systems on design controls - Align on stage gates and design reviews as the team transitions from research into development, feeding mechanical decisions into a regulatory-compliant DHF.
Qualifications
  • Bachelor’s or advanced degree in mechanical engineering or other relevant discipline.
  • Typically requires 10 years of relevant experience, including at least 4 years working with biological or chemical systems in instrumentation; medical device or IVD experience strongly preferred.
  • Strong track record driving development projects with multiple external vendors for component fabrication and assembly.
  • Direct experience working with common fabrication techniques (CNC, sheet metal, molding, forming, stamping, die-cut, 3D print, etc.) with the knowledge of the benefits and limitations of each
  • Proven technical and administrative experience with enterprise CAD software (e.g. Solidworks, NX, Creo, Onshape, or Fusion360).
  • Deep familiarity with design for manufacturing and assembly, including tolerance analysis and cost optimization.
  • Experience recruiting, hiring, and mentoring engineering team members.
  • 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.
Preferred Qualifications
  • Track record working in an interdisciplinary R&D / early product development setting, ideally in early-stage startups.
  • Experience with regulated product development under 21 CFR Part 820 and/or ISO 13485, including creating and maintaining design history files.
  • Familiarity with cell therapy manufacturing workflows, bioprocessing equipment, or related biological manufacturing.
  • Experience evaluating and working with job-specific AI tools, including using AI/LLM tools to accelerate design, documentation, and cross-team communication.
  • Experience using simulation tools (ANSYS, COMSOL, SolidWorks Simulation) for thermal, structural, or fluid analysis.

We offer our employees comprehensive benefits, including medical, vision, and dental coverage, as well as retirement savings plans. Optional benefits include Accident and Term Life offerings.

Salary.com Estimation for Principal Mechanical Engineer in San Diego, CA
$172,040 to $202,005
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