I found a couple of other views that reveal a bit more detail about this part. The second image is really big, but it does show important imformation.
- The base tapers; the bottom is wider than the top; so it’s not strip material.
- The material thickness is very uniform; so it’s probably ‘plate’ or ‘strip’ stock’ material.
- The surface texture is essentially smooth, with a ‘honed’ finish; another characteristic of ‘plate’ or ‘strip’ materials (the finish being added).
- The bottom of the base has a recess for a non-slip material; machined.
- There is a through-hole in the back; machined
- The edges of the part are ‘sharp’; again, characteristic of flat stock.
- The edges of the part show no draft; not cast or molded.
Based on these features, I would say, that starting with flat stock:
- the round hole, and the recess (for the non-slip) are first CNC milled; the endmill having a small ‘round over’ of .020" (?) to remove the sharp edges. Then,
- the perimeter is milled, freeing the part.
- It is then formed to shape, and then,
- tumbled, or blasted, (or both) with soft shot (walnut shells, plastic shot, etc.) to achieve the final surface texture. And finally,
- Clear anodized to protect the finish.
Casting would be, by far, the most expensive way to manufacture this part.
The volume of the mold would have to encompass the entire part(s), and a slide would be required to form the hole, and recess. Cycle time to allow the part(s) to cool, enough to remove from the machine, would be measured in minutes. Excess flash would need to be removed, and the surface treatment applied. Without coring it is difficult to cast parts without creating unattractive ‘sinks’ (dimples). Castings require ‘draft’, somehwere, to get them out of the mold (unless they are sandcast). This thin, flat-sectioned, part is just not economical for casting.
The extrusion process is generally used to form linear products; channel, flat, ‘angle’ , ‘rounds’, I-sections, tube, etc. Any feature(s) perpendicular to the direction of the extrusion requires secondary operations (milling, drilling, punching); in this case essentially the entire part … the perimeter, the hole, and the recess. This part may, in fact, start with an extrusion; a flat piece of strip stock.
That pretty much leaves us with a ‘bent’ component; generally termed ‘Formed.’ While the perimeter, and the round hole, on this part could be cut out using laser, or water-jet, technology, the recess on the bottom would still require a secondary milling operation. Some material would be saved because the parts could be ‘nested’ tighter on the flat stock. I suspect, however, that the added expenses of handling incurred to move the blanks to a milling station would offset those savings.
Now, having pontificated on this process, we may yet learn that these components are a naturally occurring object that Apple mines out of the ground on Saturn, and grades for size, and texture… … .