The finished product of the sand and gravel production line includes both small-grained sand and large-granularity stone. The sieving of the raw material of the finished product is mainly carried out by the round vibrating screen of the sand and gravel production equipment. The production of sand and gravel materials is divided into links such as crushing, screening and VSI Crusher. The quality control of sand and gravel aggregates is mainly based on the particle size and grading requirements of concrete aggregates. Advanced and mature crushing equipment, vibrating screens and standard aperture drying are used to ensure The grading quality standards and regulations determined by the produced concrete aggregate composite specifications. 1. Screen size control: The screen for screening coarse aggregates can be a square mesh screen made of polyurethane material. The size of the mesh is divided into 5mm, 10mm, 20mm, 40mm, 80mm and other specifications according to the aggregate gradation. The production process Except for the gravel inspection, every month or every 20,000-30,000 cubic meters of production needs to be inspected and repaired once to ensure the integrity of the production equipment. In water conservancy and hydropower projects, multi-layer screening and classification are commonly used. In small projects, because of the small amount of dashi used, drum screens can be used for individual production as needed. Second, the screen removal of impurities: the inclination angle of the screen and the amount of raw materials that need to be screened are strictly controlled, and a reliable and stable washing system is equipped for it. The layout of the water spray holes should be uniform, and the water pressure should be adjusted to the appropriate pressure during washing. The purpose is to keep the water uniformly covering the entire screen and keep the screen tools clean at all times. Therefore, after the stone material is crushed, it is also very important and key to do a good job of sieving the stone material, because the sieving of the finished material directly affects the particle shape of the subsequent finished product, and thus affects the quality of the finished product.