Mechanical Engineering Intern

About the Company

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.

About the Role

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.

Responsibilities

• Mechanical Design: 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

• CAD & Drawings: Turn 3D models into complete drawing packages for machined parts, including GD&T, materials, finishes, and inspection requirements; maintain BOMs and engineering change documentation

• Electromechanical Integration: Integrate motors, sensors, bearings, cabling, and power transmission into robust, field-ready assemblies, using off-the-shelf and custom components

• Prototyping & Fabrication: Build and instrument prototypes and test setups; design parts for 3D printing and CNC machining and choose the right process for each

• Analysis: Size components with hand calculations and run structural analysis (FEA) on load-bearing parts to validate designs under real operating conditions

• Testing & Root Cause Analysis: Plan and run tests on GRID, troubleshoot mechanical subsystems, and work with the responsible team to resolve issues and failures

• Manufacturing Readiness: Support DFM/DFA for machined, 3D-printed, and welded parts, and help build test fixtures and procedures

• Documentation: Document designs, test procedures, and results for traceability and knowledge sharing; contribute to design reviews and, where relevant, invention disclosures

• Learning from Senior Engineers: Work alongside mentors to develop reliable mechanical designs for a range of robotic tasks

Required

• 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

This is an in-person role, five days a week, in the San Francisco Bay Area. You must be based in the Bay Area or willing to relocate for the internship.

Preferred

• 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

Benefits

Why join us:

• 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

We're a startup moving fast, and being in the room together is how we build.

• Kaiser Gold HMO health plan

• Relocation support

• Daily lunches

• Pet Friendly

Arn Autonomy is an Equal Opportunity Employer. All qualified applicants will receive consideration for employment without regard to race, color, religion, sex, gender identity or expression, sexual orientation, national origin, age, disability, veteran status, or any other characteristic protected by applicable law.