I've not seen anyone CNC'ing phone cases. I can't imagine it would be very cost effective. I have seen a lot of laser engraved phone cases, as well as dye sublimated phone cases. If mobile phone cases is your thing, you should look into dye sublimation. Much cheaper and more powerful for phone cases.
Lasers : Trotec Speedy 300 75W, Trotec Speedy 300 80W, Galvo Fiber Laser 20W
Printers : Mimaki UJF-6042 UV Flatbed Printer , HP Designjet L26500 61" Wide Format Latex Printer, Summa S140-T 48" Vinyl Plotter
Router : ShopBot 48" x 96" CNC Router Rotary Engravers : (2) Xenetech XOT 16 x 25 Rotary Engravers
Real name Steve but that name was taken on the forum. Used Middle name. Call me Steve or Scott, doesn't matter.