At the basic level, a router and a rotary engraving machine are quite similar. Both move a rotating tool through a cutting path along X, Y, and Z cutting paths; however, beyond the basics, the differences are actually quite obvious. Take size, for example. In general, rotary engravers are smaller, desktop-size machines designed for smaller work pieces. Routers are larger pieces designed for larger substrates, extensive multiple copies, and large-scale projects.
Routers are also designed to go for long runs. Most routers are heavy-duty machines and are designed for more constant use. Among other unique capabilities, routers excel at faster cutting speeds; produce angled, radius, and dovetails cuts; and feature tool changers so multiple tools are always at the ready without having to start and stop to change out tools.
-Chuck Donaldson, Antares Inc.