Common machining techniques include turning, drilling, milling, sawing, die-cutting and shearing. Their function is for shearing or cutting food during chewing. The most common cutting method is shearing. It has 34 sharp teeth which are optimal for shearing flesh and grinding meat. Their teeth are adapted to shearing (cutting) relatively nonabrasive vegetation. Each shearing produces approximately of fiber per alpaca. Grinding hadrosaurids and shearing ceratopsians became extremely diverse across North America and Asia. Wool from shearing sheep is a little-used yet promising renewable growing medium. Calenders utilize downstream equipment for shearing and splicing calendered components. Tungsten tips are usually made by electrochemical etching, and platinum-iridium tips by mechanical shearing. DNA can be nicked by physical shearing, over-drying or enzymes. Indri, for instance, have teeth that are perfectly adapted for shearing leaves and crushing seeds. Scissors are hand-operated shearing tools. Longer mating times result in management problems with lamb marking and shearing etc. Viscosity is a material property which describes the resistance of a fluid to shearing flows.