Quality control

Every item has features that define its quality: for example for a fabric, strength; for a car, speed and fuel consumption; durability, strength, convenience and attractiveness are common to almost every item. Control is an obligatory part of production; it starts with incoming control, that is, checking that materials and semi-finished goods meet the technical requirements, then parts are checked during the process and the finished item at the end. The main methods are: measuring (size, shape, hardness and other parameters are determined with instruments), comparing (the item is compared with a reference sample) and flaw detection (invisible cracks and cavities are found with means such as ultrasound or X-rays). Measuring, comparing and flaw detection do not damage the part, so they are called non-destructive methods; sometimes, to learn the strength, the sample must be broken in a test, which is a destructive method. Today electronic computing technology speeds up measurement and reduces error. Poor-quality products mean wasted labour and material and disrespect to the buyer.