1. Inspection and testing: Inspection and testing are the most common and direct quality control measures. They include visual inspection, dimensional measurement, functional testing, etc. of products or services to ensure that they comply with quality standards and requirements. Inspection and testing can be carried out during the production process or before the product leaves the factory.

2. Process control: Process control is a control measure to ensure product quality by monitoring and controlling key parameters and indicators in the production process. It includes monitoring and control of input, operation and output in the production process to ensure the stability and controllability of the process, so as to ensure the stability of product quality.

3. Standardization: Standardization is a measure to manage and control quality through the development and enforcement of standards. It includes the development and implementation of work standards, operating procedures, quality standards, etc., to ensure the consistency and standardization of work processes and reduce the occurrence of variability and defects.

4. Feedback and improvement: Feedback and improvement is a kind of quality control measures by collecting and analyzing quality data, customer feedback and other information, identifying problems and improvement opportunities, and taking corresponding corrective and preventive measures. It includes establishing feedback mechanisms, continuous improvement and innovation, etc., to improve product quality and meet customer needs.