Quality control (QC) is operational techniques and activities to meet quality requirements .

 In order to understand "quality control ", we should understand how to meet the quality requirements, that is " suitability for use ". In order to achieve this ever-changing "suitability for use ", it is the responsibility of all sectors to maintain quality and to be responsible for a specified action.

Top management

They have the responsibility to track  market situation, customer response, etc. Tracking results should be translated into decisions, then into new products, or products with additional or changed properties.

Quality control

Middle managers

Their job is to understand the requirements and use the work system to meet the requirements.

Grassroots Managers and Employees

Understand the working system and meet the requirements given in the form of standard / specification. In order to perform these functions in a coordinated manner, each function must always be connected with each other and be aware of changing circumstances and requirements. In other words, everyone has to understand their responsibilities in their respective positions. For each responsibility, he/she shall select the appropriate unit of measurement, establish these measurements and implement the standards. Then, make actual measurements, explain the differences, and take action on the differences. This is the quality control function at all levels.