No one engraves skis now. Ski shops did the engraving back when it was done. I don't recall much of it after the early 70s.
I helped my dad engrave skis for our ski club, ESSC. The machine was like a pantograph.
Today, an engraving on a stolen ski could be stickered over. A friend writes his name under a binding. It old give him a positive id on the ski of it is recovered. I have been lax lately, but I do have many serial numbers of my skis.
My Head 720's and Red Stars are engraved. Everything since then I write my initials on the ski with a Sharpie. On a couple of pair I did the initials under the binding thing, too.