In the American Society of Quality (ASQ),
Quality Assurance (QA) is defined as "part of quality management focused on providing confidence that quality requirements will be fulfilled".
Dr. J.M. Juran, one of the most notable experts in quality management, believes that "QA is a series of activities that provide pieces of evidence to all things concerned. This evidence is needed to establish trust, proving that the quality function is fully deployed.”
Therefore, QA is a comprehensive and effective quality management activity for the enterprise internally; while externally it is an activity that provides evidence to all relevant parties.
Quality Control (QC), Quality Assurance (QA), and Quality Management (QM) are the three main concepts companies need to pay attention to maintain their level of quality. QC, QA, and QM are each used differently at the different stages of production.
1. Product Period
The early quality management activities (in the preliminary stage of industrialization) focused on the inspection and testing of final products, that is, the era of QC (Quality Control). Quality management in this period of time put emphasis on products. There is specific personnel (Quality Control personnel or QC personnel for short) to inspect the final products to ensure that their quality meets the requirements when the products have been completed. Later, IQC, IPQC, FQC, and even OQC derived gradually, all belong to the category of QC, focusing on inspection. While, control and inspection mean repairing the damages, revising the production plans, and controlling deliveries, which is especially important in the mature production period.
2. Customer Period
This period of time with a more detailed division of labor, strict inventory control, and accurate production plan, requires a higher level of quality management of the organization, that is, whether the quality management can start earlier from the process design and focus on the prevention, which means the era of QA (Quality Assurance) starts. This period is characterized by focusing attention on customers and managing everything around customers’ needs.
And the management concepts of system and process derive gradually with the following responsibilities generated and refined:
3. Value Chain Period
With the coming industrialization, product design, production, and marketing may be carried out in different organizations, regions, or countries, and it is difficult to gather various organizations together to design processes. Therefore, systematic management of QM (Quality Management) has become a way of building bridges between different organizations. This period mainly features the value chain. Each organization along the value chain can maximize its own value. The starting point of the value chain is the product, and the endpoint is the customer (consumer).
Quality management has gradually evolved into a philosophy of systematic management. ISO9001 is exactly a typical QM system.
QA means quality assurance, with emphasis on the word "assurance". How can we assure the quality? A strict quality assurance system needs to be set up to assure the quality of products to customers and the company.
Quality assurance is to be carried out based on the organizational structure. Quality personnel are divided into QA and QC.
QA is responsible for establishing systems, processes, quality standards and investigating the occurrence and causes of abnormalities for further improvement and follow-up, etc.
QC conducts quality inspection according to the standards/processes established by QA, including IQC, IPQC, OQC, etc.
Following is the quality assurance system of NexPCB:
The methodology should include the following processes to be allocated to different personnels:
All these processes are set up to focus on each segment of quality control, mainly to prevent quality risks in these segments. The cost for QA can be split into 2 main parts:
A quality management system is formed when these segments are intertwined.
The construction of QA system is essentially the same as that of an army. More preventive cost will be paid when taking stricter precaution. Therefore, it is necessary to find a balance to minimize the total of prevention cost + quality loss .
Philip Crosby, the well-known contemporary quality management guru, has spent his life studying the quality management theory and summarized the following four basic principles of quality management, which can help to improve the capability of QA significantly.
1. The definition of quality is conformance to requirements
The foundation of quality improvement is to make everyone do things right the first time, and the key to doing things right the first time is to clearly understand the requirements and then remove all obstacles. The management team does have three basic tasks to perform in this aspect:
Instead of making things "good", the so-called "doing it right the first time" is to make things meet the requirements. Making things "good” is a vague concept and having requirements specified is the key.
2. The system of quality is prevention
The most outstanding cost of traditional quality work is caused by evaluation. The person who takes the job of evaluation is often called the inspector in the manufacturing industry, that is, QC. QC engineers constantly evaluate and identify whether the product quality meets the requirements, whether it is qualified or not? However, such kind of evaluation is done after the event. Its main responsibility is to distinguish the product quality, which has no direct added value to the quality of products, and so can be regarded as a waste.
The key to quality assurance lies in the prevention. It pushes us to understand the working process and know how to do it properly. The secret of successful prevention is to examine the whole process and find out every opportunity that may cause mistakes. It is controllable. Every product is made up of many parts, each of which shall be addressed in order to eliminate the root cause of the problems.
The system of quality is prevention, not inspection.
3. The standard is zero defects
Developing various requirements is a well-known management method. While, little is known about the importance of complying with each of them at all times. Working standards are a means to keep a company running normally by helping everyone in the company recognize the importance of each small action. When employees in a company are not encouraged to do everything completely right, many actions will be neglected and the results are questionable. A company composed of millions of individual actions cannot afford to off-track actions 1% or 2% of them. Mistakes have traditionally been viewed as inevitable. In fact, this kind of self-fulfilling prophecy will come true as long as the wrong working standard exists.
The so-called "zero defect" refers to a working standard of management, not to the products. Provided that employees clearly understand the requirements, they will make every effort to meet the requirements. But if the requirements, such as "excellence" and "AQL", appear ambiguous, the performance of employees will be spotty. But if we insist on "zero defect", "no defect" or "doing things right the first time", all can learn to prevent problems before they occur.
4. The measurement of quality is the price of nonconformance
Money, a new standard for measuring quality, has gradually emerged in the current corporate world. The amount of quality cost is adopted to measure the quality, or the quality management. The cost of quality can be divided into two fields: Price of Nonconformance (PONC) and Price of Conformance (POC). PONC refers to the cost of all things done wrong, which is more than 20% of turnover in the manufacturing industry. POC refers to the money spent on doing things right, covering cost of most professional QM departments, preventive measures and quality education. This cost accounts for about 2-3% of turnover in a well-run company.
Consequently, PONC would be an appropriate indicator to measure quality.
QC and QA have jointly formed a product quality assurance system to externally reassure customers that the factories produce and deliver products according to their requirements; and internally, to reassure all levels of the management. Here is an inappropriate example, QC is the policeman and QA is the judge. QC is responsible for catching people who break the law, but policeman cannot prevent people from committing crimes and ultimately convicting others. While QA, as the judge, is to formulate laws to prevent crimes and pronounce judgment based on the law.