The spot check is conducted in accordance with GB / T 6971-2007 test method of feed crusher and GB / T 9480-2001 agricultural and forestry tractors and machinery, lawn and gardening power machinery The preparation rules of operation instructions and other requirements specified in the standards, safety requirements, productivity, power consumption per ton of material, noise, temperature rise of bearing, poor quality of hammer (flat tooth), hardness of hammer (flat tooth), safety signs and operation instructions