can someone explain to me what burnishing is please

thanks

 

Burnishing, Roller Burnishing

 

Good link info. Usually looks like a boring tool but with a set of rollers on it. Leaves a lovely finish, Ra in double digit micron range i.e. you feels like glass to the finger. Drills and milling will give a comparable finish when drill/tips are new but a burnisher will do thousands and thousands of bores whereas normal carbide or even diamond will have keeled over by then. Has to be rough cut first though, unlike a drill etc.