Stone less than 50mm enters sand making machine though conveyor belt. Stone is crushed by hitting other stones. Material falls down to impellor cavity. Under great centrifugal force, it hits material that coming downwards. After hitting each other, they force a vortex between impellor and shell, and hit each other several times; finally smaller stone comes out, and goes to vibrating screen. Satisfactory material is transported to sand washing machine; however overlarge material will go back to sand maker to be recrushed. Output sizes can be made according to customers' requirement. If input size is larger than the designed size, other crushing equipment will be necessary.