We discussed the concept of SFM in an earlier post I last year. The consensus we came to and that I agree with upon further review is that SFM doesn’t really matter for CNC router milling. The origins of SFM came about with perhaps roots in thermal heat generation and metal melting points but no one has a good story and they don’t seem to matter. What matters more is the chipload, as that is proportional to the heat generated since that is how much material you are removing per cut. With CNC companies like Datron, PocketNC, and Kern milling aluminum on 50k spindles, we can certainly do it with 30k routers.
The only thing to be aware of is that at higher SFMs, you do generate more heat and misting some IPA/H2O helps alleviate that and provide lubrication to evacuate chips more effectively.