A well-known valve manufacturing company's four-way directional valve faced the problem of loose sealing of the valve core during mass production.Through the introduction of Hai Ruisi's special inspection solution, accurate inspection of many key parts such as the flatness of the sealing surface and the welds of the valve body has been achieved.After the implementation of the project, the product defect rate dropped from 1.2% to less than 0.008%, the annual quality cost was reduced by 4.2 million yuan, and it obtained inspection-free supplier qualifications from multiple mainstream air-conditioning manufacturers.