Marking & Coding
Laser marking and coding are closely related applications. Marking involves physically creating a contrasting surface mark on the target material by discoloration or surface melting. Coding is a type of marking, however instead of marking with a static graphic or text, the mark varies, either from item to item as in a serial number, or from batch to batch as in an expiration date. The single biggest advantage for laser marking is the mark is permanent, and cannot smear or rub off.
Surface discoloration produces a contrasting mark by creating a heat-induced color change in the target material; there is no melting or removal of material. This is the most efficient marking process since speeds are very fast and power requirements are low, typically below 25 W.
Surface melting produces a contrasting mark by physically melting the material surface. The melting creates a color change in the material that contrasts with the unaffected (unmarked) areas. Typically, the melted material changes density and volume, creating a raised surface.