[ additive manufacturing ]
a challenge to manufacture . And because of the incipient nature of the current SOFC market , impellers are produced in relatively small batches , and economies of scale are difficult to realize .
How to bring that cost down ? Additive manufacturing ( AM , aka 3D printing ) provided a compelling answer . While the original project with FuelCell Energy was evolving , Mohawk was also getting calls from R & D groups looking for help with their own fuel-cell component designs . “ Because many of these manufacturers and integrators were still at the research stage , each one had a different operating condition in mind ,” says Cordova . “ Using traditional manufacturing , to make just the handful of the custom impeller wheels or volutes they wanted , would have been extremely expensive . So that ’ s where we started looking at AM ; we did our own research into AM system makers and connected with laser-powder-bed fusion ( LPBF ) provider Velo3D .”
Collaborating on capabilities
With its goal of reducing costs and improving performance of SOFCs , the DOE is enthusiastic about innovative manufacturing methods such as AM , says Cordova . “ Their funding [ through The Small Business Industrial Research Project ] supports our current partnership with Velo3D as well as our previous one with FuelCell Energy . An additional benefit is that this work is helping advance 3D printing technology in general as we learn more and more about its capabilities and potential .”
Velo3D ’ s Mohawk-project leader Matt Karesh agrees . “ Working hand in hand with companies like Mohawk , who are willing to collaborate with us and give us feedback , drives progress on our internal process parameters and capabilities , and helps direct us as to how to make our print methodologies better ,” he says .
Cross-section of a Mohawk AORB highlights the main internal components
A nice price surprise
The switch to AM was an eye-opener : “ Our traditional , subtractively manufactured impeller wheels were running up to $ 15,000 to $ 19,000 apiece ,” says Cordova . “ When we 3D printed them , in small batches of around eight units rather than one at a time , this dropped to $ 500 to $ 600 – a very significant cost reduction .
“ As well as cutting manufacturing costs , LPBF is the one technology that could provide us with the design flexibility we were looking for . AM is indifferent to the number of impeller blades , their angles , or spacing – all of which have a direct impact on aerodynamic efficiency . We now have the geometric precision needed to achieve both higher-performance rotating turbomachinery designs and reduce associated manufacturing costs .”
Picking the perfect alloy
For 3D printing impellers on a Velo3D Sapphire system ( at Duncan Machine , a contract
32 Hydrogen Tech World | Issue 8 | February 2023