Post 3: Getting it made
Mid-Sept 2020 | By: Thuan D.
Even before sending parts out for quote, it was very clear that:
we wanted the enclosure to be a solid aluminum housing
it would be the most expensive single part of the whole thing
A lot of work was done to optimize the design to minimize machining operations and machining time. One of the difficulties that we ran into was the geometry required to mount the mechanical switches. In a plate mount design that is most commonly found, the plate is waterjetted so the sharp corners required to mount the mechanical switches aren’t a problem. In machining, this requires tooling and longer machining time and is a bit tougher to get right.
We sent it out to various vendors, in the US and overseas with requests for prototype quantities and quantity pricing breakdowns. We eventually settled on a machining vendor in the US that we felt had:
good pricing breakdown at reasonable quantities
good capabilities (tooling, surface finishes, consistency, ability to scale, etc),
good potential for us to work with and learn from
After a round of DFM (design for manufacturing) feedback, we kicked off prototype quantities (ouch! very expensive), to test their capabilities and start experimenting with finishing options. I love the look of a well-made, high quality aluminum part, and worked with the machining vendor to try and find the right one. There are lots of different types of finishing operations, and even within each of the operations, there’s a lot of different parameters that can be tuned. We worked with the vendor to find the right look and tested parts with both anodization & with no anodization.
Anodization is a process by which a hard-oxide layer is developed on the surface of the aluminum that protects it from contaminants. Naturally, aluminum doesn’t rust and develops this protective layer so is generally pretty robust, especially in mild environments such as an office desk. If we could, we wanted to not have to add another operation and add cost to the parts. However, we found that despite the robustness, a non-anodized aluminum enclosure had quite a porous surface and during our testing would pick up contaminants (mostly grease, oils, etc). While this doesn’t effect the durability and structural integrity of the housing, we wanted to stay true to our dedication to creating a high quality product, and worked with the vendor to find an acceptable clear anodization. It also added some depth to the already stunning media-blasted finish, so that was also a plus.
It took about 2 months to get from the design stage to get prototypes in-hand, but the time was well-spent to get the exact unit that we had envisioned. We were happy with the decisions and experimentation done to get a high quality enclosure with a stunning finish that celebrates the natural look of aluminum.
One of the potential finishes that we were considering, but didn’t end up going with.
