Lubrication A: is the process or technique of reducing wear between surfaces by using a lubricant between the surfaces. B: is a special liquid that performs three main functions during machining. It lubricates the cutting action, carries off the heat generated, and flushes(冲洗) the chips(切削). C: is the material being machined. It can be any material and any shape. In the machine shop it usually refers to round or flat pieces of metal ready to be machined.