1 transportation of materials containing sharp objects, sharp objects may well be scratch conveyor belt, if the scratches are deep, will be at the material time, especially when those heavy items, it is easy to tear. 2, belt deviation occurs, if the conveyor belt deviation occurs, it will cause uneven loading of conveyor belt, in some places, in some places by force. In such cases where force will be very prone to tearing. 3, the cassette is also easy to cause the conveyor belt torn, when large quantities of materials falling within the chute when the conveyor belt will be jammed, making conveyor belts will not operate properly, but the motor continues to run, makes conveyor belts in the context it is prone to tearing. 4, conveyor belts are generally rubber belt, therefore it is prone to aging phenomenon, if delivery of high temperature, corrosive material, can accelerate aging. Belt once the aging are prone to tearing.