Quality control

In engineering and manufacturing, quality control and quality engineering are used in developing systems to ensure products or services are designed and produced to meet or exceed customer requirements. These systems are often developed in conjunction with other business and engineering disciplines using a cross-functional approach.

Quality assurance (quality control) covers all activities from design, development, production, installation, servicing and documentation. Statistics shows, less than 5% of the world’s food is safe to consume. This introduced the rules: " fit for purpose" and " do it right the first time". It includes the regulation of the quality of raw materials, assemblies, products and components; services related to production; and management, production, and inspection processes.

Failure testing. A valuable process to perform on a whole consumer product is failure testing (also known as stress testing), the operation of a product until it fails, often under stresses such as increasing vibration, temperature and humidity. This exposes many unanticipated weaknesses in a product, and the data is used to drive engineering and manufacturing process improvements. Often quite simple changes can dramatically improve product service, such as changing to mold-resistant paint or adding lock washer placement to the training for new assembly personnel. Failure testing or destructive testing is a valuable tool of earthquake engineering.

Statistical control. Many organizations use statistical process control to bring the organization to Six Sigma levels of quality, in other words, so that the likelihood of an unexpected failure is confined to six standard deviations on the normal distribution. This probability is less than four one-millionths. Items controlled often include clerical tasks such as order-entry as well as conventional manufacturing tasks.

Traditional statistical process control in manufacturing operations usually proceeds by randomly sampling and testing a fraction of the output. Variances of critical tolerances are continuously tracked, and manufacturing processes are corrected before bad parts can be produced.

History. When the first specialized craftsmen gave manufacturing tools for others, the principle of quality control was simple: " let the buyer beware".

Early civil engineering projects, however, needed to be built to specifications. For instance, the four sides of the base of the Great Pyramid of Giza are perpendicular to within 3.5 arc-seconds. During the Middle Ages, guilds took the responsibility of quality control upon themselves.

Royal governments purchasing material were interested in quality control as customers. For instance, King John of England appointed a certain William Wrotham to supervise the construction and repair of ships. Some centuries later, but also in England, Samuel Pepys, Secretary to the Admiralty, appointed multiple such overseers.

The Industrial Revolution led to a system in which large groups of people performing a similar type of work were grouped together under the supervision of a foreman who also took on the responsibility to control the quality of work manufactured.

Quality assurance has developed a good deal during the last 80–90 years (in about 20 year intervals) from its inception to the current state of the art.

Exercise 5. Find in the text the following word-combinations and translate them to your native language:

Quality engineering, customer requirements, the world’s food, a cross-functional approach, " do it right the first time", unanticipated weaknesses, manufacturing process improvements, destructive testing, critical tolerances, specialized craftsmen, Royal governments, a good deal.

Exercise 6. Classify the words and word-combinations, fill in the table:

Engineering, manufacturing, quality control, systems, business, disciplines, design, documentation,

failure testing, operation, statistical control, product, process, Pyramid, Revolution.