Sherpa Design Collaborates with Monterey Bay Aquarium Research Institute to Address Manufacturing Challenge for Underwater Robot
The Monterey Bay Aquarium Research Institute (MBARI) develops and deploys innovative technology to study the ocean. MBARI engineers are advancing the integration of biological sampling tools within autonomous underwater vehicles (AUVs). MBARI aims to improve how samples are collected and processed, while remaining focused on efficient workflows for the biologists and resource managers who work in unpredictable ocean settings.
To support this effort, MBARI required a custom fluid manifold for its Environmental Sample Processor (ESP), a portable robotic laboratory capable of autonomously collecting and processing up to 60 water samples. The component—a toroidal ring with 60 dual fluid ports—presented a unique set of requirements, including pressure resistance, chemical compatibility, and dimensional accuracy across a highly complex internal geometry.
Design and Manufacturing Challenges
Earlier iterations of the part had been produced using an alternative 3D printed platform, but MBARI observed several limitations during testing and use, including brittleness, reduced performance across temperature extremes, and incompatibility with the system’s cleaning protocol (water with 10% bleach).
MBARI evaluated multiple paths forward, including metal additive manufacturing. While technically viable, metal printing introduced cost and complexity considerations that made it less attractive for this application. As a result, MBARI explored polymer additive manufacturing using Carbon’s Digital Light Synthesis™ (DLS™) technology.
Through the Carbon partner network, MBARI engaged Sherpa Design to support both the design-for-additive-manufacturing (DfAM) strategy and fabrication of the part. Sherpa differentiates itself from many other production partners by offering design and product development services in addition to prototyping and batch production runs.
Evaluating Additive + Subtractive Manufacturing
Initial review of the CAD model and reference drawings made it clear that the part’s internal fluid passages and overall geometry were well-suited for additive manufacturing. However, certain external features, including threads, sealing surfaces, and interfaces requiring tight concentricity, exceeded what could be achieved with printing alone.
The team identified a hybrid approach: combining Carbon DLS printing with post-process 5-axis CNC machining. This strategy leveraged additive manufacturing for geometric complexity while using subtractive processes to achieve required surface finishes and tolerances.
Material Selection: Carbon EPX™ 150
Material evaluation focused on machinability, chemical resistance, and dimensional stability. Sherpa quickly identified Carbon’s EPX 150 material for the application because of its exceptional temperature and chemical resistance as well as its functional toughness.
EPX 150 shows excellent retention of material properties via temperature/humidity cycling and thermal shock and is suitable for long-term use at temperatures ranging from -30°C to 125°C. With deep sea temperatures as low as 1°C, EPX 150 was the obvious choice.
The material also shows resistance to exposure of a wide variety of chemicals, including water and substances like bleach, which was critical for this application, with no change in visual appearance and minimal change in tensile properties.
A trial part was printed and manually machined to validate feasibility, demonstrating that the material could support both additive production and subsequent CNC finishing.
Designing for Post-Machining
Sherpa is a Carbon partner focused on the full workflow from product development to design for additive manufacturing and all the way through to small batch production. The Sherpa team can start with anything– a napkin sketch or fully developed CAD. Through a series of DFM changes, printing, and feedback, the team can improve costs, reduce time, and even address part aesthetics.
Sherpa applied this expertise to the MBARI application, and following collaborative reviews between both manufacturing teams, features were categorized based on whether they could be produced additively or required machining.
The workflow included:
- Iterative test prints and dimensional analysis to tune printed features
- Programming multi-step machining operations (drilling, reaming, T-slot cutting) to maintain concentricity across fluid ports
- Revising the CAD model to add machine stock and remove features better produced subtractively
Two key DfAM insights emerged:
- Features requiring tight tolerances and concentricity are best addressed through CNC machining
- Adding sufficient machine stock during printing enables more reliable post-process cleanup and finishing
In practice, this shifted the manufacturing split from an initially print-heavy approach to a balanced combination of additive and subtractive processes.
Outcomes
The final component met all client-specified dimensional requirements and underwent pressure testing up to 500 psi without leakage. The part is now deployed inside MBARI’s Environmental Sample Processor and is currently undergoing field trials aboard the institute’s long-range autonomous underwater vehicle (LRAUV).
“As a Carbon production partner, Sherpa Design’s goal is to act as your guide and take you from prototyping to scaled production. We specialize in product development, design for additive manufacturing, and small batch production. Our team can start with anything from a napkin sketch to fully developed CAD. While MBARI came prepared with a design, we were able to guide them through DFM iterations with our additive engineers and in-house machine shop to get them to a successful working design and manufacturing process for their application.”
This project highlights how Carbon’s engineering-grade materials and DLS technology, combined with the DfAM and manufacturing expertise of Sherpa, can support complex, performance-driven applications where traditional manufacturing approaches may fall short.