Mechanical Engineering Intern

Arn Autonomy • South San Francisco, CA

5d • Onsite

About The Position

Arn Autonomy is building autonomous, non-humanoid robotic systems to construct infrastructure in extreme, unstructured environments, starting with next-gen construction job sites. Our vision is to disrupt the $16 trillion global construction industry by pioneering a new Deep Tech philosophy that blends robotics, AI, and systems engineering at the frontier. Our flagship product, GRID, is an autonomous rebar-tying robot deployed with rebar and concrete contractors on live job sites. We're seeking a Mechanical Engineer Intern to join the team building GRID, our rebar-tying mobile robot. You'll work on real hardware: the tying mechanism, gantry, chassis, and powertrain. This is a hands-on, cross-disciplinary role spanning mechanical design, prototyping, and system-level testing, in close partnership with our software, electrical, and manufacturing teams. You'll get mentorship from senior engineers and a high degree of autonomy, and you'll see your designs built, tested, and run on live construction job sites.

Requirements

• Completed a bachelor's or graduate degree from an accredited program in Mechanical Engineering, Robotics, Mechatronics, or a similar field, with no ongoing coursework, so you can commit to the internship full time and in person
• Working knowledge of statics, mechanics of materials, and machine design fundamentals
• Proficiency in at least one CAD package (for example SolidWorks, Fusion, CATIA, or similar), with a working understanding of GD&T and tolerancing
• Hands-on experience building or testing mechanical or electromechanical hardware, from coursework, a robotics team, or personal projects
• Ability to analyze problems and work with teammates to find well-reasoned solutions
• A self-starter with proven examples of self-directed learning, who stays productive with minimal support
• Available to work full-time (40 hours/week) for an internship lasting at least six months
• Authorized to work in the United States

Nice To Haves

• Proficiency in a second CAD package and strong GD&T and tolerance-stack fundamentals
• Experience running FEA and sizing structures by hand calculation
• Practical knowledge of CNC machining, 3D printing, and welded fabrication, and when to choose each
• Experience sizing electric motors and gearboxes from payload, speed, slope, and duty-cycle requirements
• Exposure to mobile or outdoor robotic platforms (AMRs, construction or ag equipment, off-road vehicles) and how wheeled or tracked chassis behave over uneven terrain
• Familiarity with IP-rated enclosures for dusty or wet environments, and with reliability testing
• Prior internship, co-op, or substantial project experience (robotics clubs and competition teams count)
• Ability to rapidly learn, evaluate, and adopt new AI tools and platforms as project needs evolve

Responsibilities

• Design mechanisms, gantry, chassis, and structural components for a mobile robot operating outdoors, with durability, serviceability, and performance in dust, vibration, temperature swings, and weather in mind
• Turn 3D models into complete drawing packages for machined parts, including GD&T, materials, finishes, and inspection requirements; maintain BOMs and engineering change documentation
• Integrate motors, sensors, bearings, cabling, and power transmission into robust, field-ready assemblies, using off-the-shelf and custom components
• Build and instrument prototypes and test setups; design parts for 3D printing and CNC machining and choose the right process for each
• Size components with hand calculations and run structural analysis (FEA) on load-bearing parts to validate designs under real operating conditions
• Plan and run tests on GRID, troubleshoot mechanical subsystems, and work with the responsible team to resolve issues and failures
• Support DFM/DFA for machined, 3D-printed, and welded parts, and help build test fixtures and procedures
• Document designs, test procedures, and results for traceability and knowledge sharing; contribute to design reviews and, where relevant, invention disclosures
• Work alongside mentors to develop reliable mechanical designs for a range of robotic tasks

Benefits

• Work on a real product: your designs ship on GRID, a robot deployed on live construction job sites
• Hands-on experience in mechanical design, integration, testing, and debugging on real hardware
• Collaborate with electrical, software, and manufacturing engineers in a small, fast-moving team
• Mentorship and professional development from senior engineers
• Kaiser Gold HMO health plan
• Relocation support
• Daily lunches
• Pet Friendly

What This Job Offers

• Job Type: Full-time
• Career Level: Intern