Keyboard Builders' Digest / Projects
Cast aluminum keyboard case
u/earth_hair made a moon-themed cast aluminum keyboard case for a design and manufacturing class.
Published June 9, 2022

This gorgeous aluminum case, cast by earth_hair and posted on r/mk, features real crater patterns of the Moon.
It all started out as a pandemic project. The keyboard and the CAD model were already done. (The base keyboard PCB is mjpauly's Phase btw.)
After rapid cardboard prototyping the crater pattern was printed (FDM + SLA), then came the casting process.
Some milling, smoothing, tapping, sanding and bead blasting later this unique keyboard was born.
The casting wasn't the tedious part. I got lucky not needing to re-cast either half. If anything, sanding all the sides over and over again after milling them flat was what was really tedious!
Check out this elaborated photolog on imgur with lots of WIP shots.
When asked about his inspiration, earth_hair told me:
The inspiration for the moon texture came when I was thinking about what I could do to the pattern to complement and accentuate a sand-cast finish. The sand-cast finish adds small-scale details which add texture to the craters which isn't in the original 3D model. And the craters in turn help hide imperfections in the sand-cast finish, such as when sand sticks to the pattern when pulling.
Casting was the manufacturing method used since it was one of the core processes taught in his class (along with milling, turning, and welding).
According to the designer, of these processes, casting lets you manufacture relatively complex geometries since you can 3D print the pattern. However, adherence to sand-casting design rules is necessary to ensure the part comes out OK.
One such important design rule is adding "draft" to the design, sweeping vertical faces backwards so that the pattern pulls out of the sand cleanly.
I didn't get a super clean pull on either the left or the right hand patterns and that influenced my decision to face those sides vertical on the mill instead of leaving them with a sand cast finish (the texture you get from the sand casting process without sanding/polishing).
The top crater faces turned out well, so those were kept as-is.
With regards to his experiences, earth_hair adds:
It's certainly not the most efficient or functional way to design a keyboard case but it was very fun to make. The objective of making just one copy let me invest a lot of time and energy into designing and making it with methods that are less common in scaled manufacturing.
Published on Thu 9th Jun 2022. Featured in KBD #82 (source).