One: the rolling pressure is too large, and the local stress of the roll is too large.
Two: the roller has a history of sticking in the past, and no cracks have been found after broaching or grinding. Under the pressure of large rolling force, meat will fall off at the crack, the roll will explode, and the roll will be broken seriously.
Three: the physical and chemical indexes of the roller itself are uneven, which will cause the roller to break in inappropriate parts.
Four: My humble opinion. . .