First attempts to regulate the quality of production
Quality control in the Middle Ages was undertaken by guilds, which assumed responsibility on behalf of their members, by imposing and upholding specific criteria for guild participation.
Quality control was also of great interest to the monarchical governments, who were functioning as purchasing customers. To this end, William Wrotham was appointed by King John of England to oversee ship repair and constructions. It took several hundred years for more overseers of this kind to be designated by the Secretary to the British Admiralty, Samuel Pepys.
Before the onset of the Industrial Revolution that divided labor and mechanization extensively, workers were able to control the quality of their own production. The Industrial Revolution resulted in the adoption of a system where a supervisor was designated to oversee the production quality stemming from the work of specialized workers, who functioned in large groups.
Production during the war
During World War I, the process of manufacturing achieved a higher level of complication, in the sense that supervised worker groups became larger. It was at this time that piece work and mass production flourished, bringing several side effects along; although workers were able to make more money, since productivity rose, the overall quality dropped due to poor workmanship being incorporated in the lines of assembly. To deal with this, full-time supervisors were employed with the purpose of identifying, quarantining, and, if possible, reversing product quality misfires. This form of quality control during the 1920s and 1930s ultimately allowed quality inspection functions to grow and organize independently from production; the growth also led to the employment of superintendents.
History of quality
Quality began to be systematically studied in the 1930s, mainly in the U.S.A., in the context of industrial manufacturing, with the cost of rework and scrap drawing a bit of attention. The onset of World War II created additional needs in the field of quality control, due to the extent that mass production reached, thereby leading to the development of a better quality control tool, namely the Statistical Quality Control, or SQC. One of the founders of SQC is considered to be Bell Labs’ Walter A. Shewhart, well-known for his notable, single-page, 1924 memorandum.
SQC is based on the notion that it’s impossible to check every single manufactured piece and categorize it into acceptable and non-acceptable batches. It provides the base for an extended inspection phase and a more efficient inspection carrier, via the use of statistical tools like control charts and sampling, even in cases where it’s impossible to employ complete inspection. Appropriate statistical methods enable the manufacturer to inspect the overall quality of the production line or the batch by sampling and testing a predetermined percentage of the total production, in order to achieve the desired level of confidence.
After the end of World War II, many countries that saw their production infrastructure being annihilated during the war, began rebuilding it. Japan’s rebuilding was overseen by general MacArthur. It was during this time that MacArthur assigned key positions to two important individuals that helped shape quality control in the modern age: Joseph Juran and W. Edwards Deming. Their main contribution was the promotion of the concepts of collaboration towards quality to the technical and business groups of Japan, who, in turn, employed them to redevelop the country’s economy.
In the United States, despite the efforts of many to introduce advanced quality control techniques to the country’s industry, traditional Quality Control via sampling and inspection continued to be the mainstay of removing defective products from assembly line, thereby overlooking all developments in the field for many years.