Hello! Normal operation of conveyor belt, the belt speed roller speed of not less than 95%. If the roll is not enough friction with the conveyor belt, conveyor belt prone to slipping on the phenomenon. Caused by the friction roller and the conveyor belt is not enough reason for many common are: tension is not enough, load start, roller surface friction coefficient is not enough and so on. Tension is not enough reasons: not enough tension journey, with emphasis on weight is not enough belt is too long, etc.; roller surface friction coefficient is not enough number of factors: wear rubber-coated roller too, with body too wet or sticky with oil , with the surface of the sticking of material (easily water-soluble up to).