As the head of the operation and maintenance center of the installation engineering department of Zhenghe, Mr. Zhao clearly realized that "serving customers is the foundation of the enterprise's survival", and carried out on-site construction management and engineering after-sales service in strict accordance with the IS09001 quality management system standard. After the completion and acceptance of the project, he will be fully responsible for the technical support and maintenance of the system guarantee in the after-sales service stage of the project.