Efficient and low-cost hollow-out method for sapphire wafer bar

The invention discloses an efficient and low-cost hollow-out method for a sapphire wafer bar. Problems that an existing method for hollowing out a bar is poor in chip removal effect and large quantities of cooling liquid cannot reach a bar hollowed-out portion are solved. The efficient and low-cost hollow-out method mainly includes steps of (1), fixing a sapphire crystal on a machine tool, and turning on a cooling water pipe to continuously feed cooling liquid into the sapphire crystal; and (2), moving a cutter to a position to be processed and forming the sapphire wafer bar by more than one processing cycle. Each processing cycle includes hollowing out the bar, lifting the cutter, removing chips and moving the cutter downwards. In the step of hollowing out the bar, the rotational speed of the cutter ranges from 300r/min to 500r/min, and the bar begins to be hollowed out; in the step of lifting the cutter, the cutter is quickly lifted up when the depth of a hollowed-out portion of the bar ranges from 2mm to 5