Add or subtract before you multiply? I say add.

“Sean, why do they call it “additive manufacturing”? Don’t I have enough buzz words to remember already?…”

Ok, well now that these printed or sintered or layered parts are (in some processes) good enough for immediate actual use in the real world and not just test parts, there needed to be a new terminology to get away from “prototypes”. Since it’s all based on the addition of layers, and since you only build what’s in the CAD model, it’s “additive” in the sense that none of the primary material is removed. If you think of a typical metal machined part, you start with a chunk of metal and machine away the bits you don’t want, this is subtractive (not to mention a waste of expensive raw material — Titanium is not cheap!)

Subtractive machining of complex parts also requires large elaborate machinery, skill/risk of operator error, and takes time for drawings and conversations communicating with the job shop, programming/setting up machines, scheduling delays, and inspection of parts for conformance. Coupled with this are the limitations placed on the design in order to “design for manufacturing” instead of “design for function”.

So if preparing products for later mass production of multiple units, I say first “add” don’t “subtract” if you can help it.