US Patent 9521929 Self cleaning tribological coated tobacco and herb grinders

A tobacco and herb grinder suitable for grinding many dried plant products, having two interfacing sets of knives or pins with low friction omniphobic coated parts that inhibit the adherence of plant material buildup. The grinder inhibits the accumulation of resins or oils and, thus reduces or eliminates binding and the necessity for removing debris by use of a particular combination of knife blades and coatings.