Honeycomb filters are often used in electronics packaging applications to keep radiation in but allow airflow through. Implementing them, however, can be a trick, especially on a small 1RU chassis (a standard height for rack mounted equipment). This part replaces 54 parts in a typical installation and simplifies assembly/design time drastically.
Companies that sell them provide stock options where much of the shape is taken up by a picture frame which chokes off the flow as they get smaller (and small fans are the most sensitive to choked flow). Don’t expect a custom shape from these suppliers either unless you plan to buy a whole bunch of them.
Not only is it hard to get the right part, but then you have to mount it on your sheet metal chassis with rivets, captive nuts, etc. Then you have to mount the fan and form a plenum to direct the airflow between them. The fan mounting hardware is hard to work with and includes a lot of parts. The plenum needs to create a seal against the main chassis as well as any cover that goes on top so you need complicated gasketing, hand-installed RTV, or a complicated weld. It’s hard to seal up all the little spots around the inside of the bends of the different sheet metal parts– hard for design as well as hard for assembly– which means it costs much more. The resulting shape adds a lot of loss to the airflow as well just because of the odd geometry and square corners.
This design is easy to customize, maximizes the airflow opening, minimizes the plenum losses for little fans, and is very easy to install. It replaces 54 parts plus a lot of design/assembly time.
Below you can see two images of the status-quo design for mounting a fan in a 1RU chassis as well as one image of the 3D printed part installed in the chassis. Note how much more efficient the latter design is.