QA: Quality assurance, quality assurance, through the establishment and maintenance of quality management system to ensure product quality without problems. Generally, it includes system engineer, SQE (supplier quality engineer), CTS (customer service technician), 6sigma engineer, calibration and management of measuring instruments, etc. QA should not only know where the problems are, but also know how to formulate solutions to these problems and how to prevent them in the future. QC should know to control only the problem, but not necessarily why.
To make an inappropriate analogy, QC is a policeman and QA is a judge. QC only needs to catch people who break the law, but can't stop others from committing crimes, and finally convict others. Judges only make laws to prevent crimes and decide the results according to the laws.
To sum up, QC: mainly focuses on the quality inspection activities afterwards, and allows default errors. Expect to find and select errors. QA is mainly a quality assurance activity in advance, focusing on prevention. It is expected to reduce the probability of error. QC is the operation technology and activities to make products meet the quality requirements, including inspection, correction and feedback. For example, after QC inspection, defective products are found and rejected, and then the bad information is fed back to relevant departments to take improvement measures. Therefore, the control scope of QC is mainly in the factory, and its purpose is to prevent unqualified products from being put into production and transferred out of the factory, to ensure that products meet the quality requirements, and only qualified products can be delivered to customers.
QA is to provide trust to meet customers' requirements. Even if the customer is sure that the products you provide can meet his requirements, you should leave evidence from the beginning of market research to the later review of customer requirements, product development, order taking and material procurement, incoming inspection, production process control and delivery, after-sales service and other stages to prove that every step of factory activities is carried out in accordance with customer requirements.
The purpose of QA is not to ensure product quality, but to ensure product quality is the task of QC. QA is mainly to provide assurance, so it is necessary to manage the whole process from understanding customer needs to after-sales service, which requires enterprises to establish a quality control system, formulate corresponding documents to standardize the activities of each process and leave evidence of the implementation of the activities in order to provide trust.
This kind of trust can be divided into internal and external. Externally, even if customers are assured that the factory produces and delivers products according to their requirements, internally, let the boss be assured, because the boss is the first person responsible for product quality, and he will take full responsibility for product quality accidents. This is also the main requirement for the state to formulate the product quality law to urge enterprises to really pay attention to quality. Therefore, in order to avoid taking quality responsibility, the boss must use documents to standardize various activities and leave evidence.
However, it is impossible to know whether the employees in the factory operate the boss according to the document requirements. This requires QA to audit on behalf of him to find out whether he has complied with the document requirements, so as to convince the boss that the activities in the factory are carried out in accordance with the document requirements and reassure him.
Therefore, the main difference between QC and QA is that the former is to ensure that the product quality meets the requirements, and the latter is to establish a system to ensure that the system runs as required, thus providing internal and external trust. At the same time, QC and QA have the same points: QC and QA need to verify whether the products meet the specified requirements, such as QC testing the products according to the standards, QA conducting internal audit to verify whether the system operates according to the standards, and QA conducting shipment audit and reliability test, such as verifying whether the products have carried out various activities according to the regulations and whether they can meet the specified requirements to ensure delivery.