NEED FOR INSPECTION
Industrial inspection has acquired significance in recent times and has a systematic and scientific approach. Prior to the industrial revolution, craftsmen used to assemble the different parts by hand and, in the process, consumed a lot of time. They were entirely responsible for the quality of their products. Inspection was an integral function of production. Since theindustrial revolution, many new manufacturing techniques have been developed to facilitate mass production of components.
In modern manufacturing techniques, a product has to be disintegrated into different components. Manufacture of each of these components is then treated as an independent process.
F.W. Taylor, who has been acknowledged as the father of scientific management of manufacturing industry, created the modern philosophy of production and also the philosophy of production metrology and inspection. He decomposed a job into multiple tasks, thereby isolating the tasks involved in inspection from the production tasks. This culminated in the creation of a separate quality assurance department in manufacturing industries, which is assigned the task of inspection and quality control.
Inspection is defined as a procedure in which a part or product characteristic, such as a dimension, is examined to determine whether it conforms to the design specification. Basically, inspection is carried out to isolate and evaluate a specific design or quality attribute of a component or product. Industrial inspection assumed importance because of mass production, which involved interchangeability of parts. The various components that come from different locations or industries are then assembled at another place. This necessitates that parts must be so assembled that satisfactory mating of any pair chosen at random is possible. In order to achieve this, dimensions of the components must be well within the permissible limits to obtain the required assemblies with a predetermined fit. Measurement is an integral part of inspection. Many inspection methods rely on measurement techniques, that is, measuring the actual dimension of a part, while others employ the gauging method. The gauging method does not provide any information about the actual value of the characteristic but is faster when compared to the measurement technique. It determines only whether a particular dimension of interest is well within the permissible limits or not. If the part is found to be within the permissible limits, it is accepted; otherwise it is rejected. The gauging method determines the dimensional accuracy of a feature, without making any reference to its actual size, which saves time. In inspection, the part either passes or fails. Thus, industrial inspection has become a very important aspect of quality control.
Inspection essentially encompasses the following:
1. Ascertain that the part, material, or component conforms to the established or desired stan-dard.
2. Accomplish interchangeability of manufacture.
3. Sustain customer goodwill by ensuring that no defective product reaches the customers.
4. Provide the means of finding out inadequacies in manufacture. The results of inspection are recorded and reported to the manufacturing department for further action to ensure production of acceptable parts and reduction in scrap.
5. Purchase good-quality raw materials, tools, and equipment that govern the quality of the finished products.
6. Coordinate the functions of quality control, production, purchasing, and other departments of the organizations.
7. Take the decision to perform rework on defective parts, that is, to assess the possibility of making some of these parts acceptable after minor repairs.
8. Promote the spirit of competition, which leads to the manufacture of quality products in bulk by eliminating bottlenecks and adopting better production techniques.
