A quality control inspection involves the use of trained, experienced inspectors who check products against pre-established performance standards. During an inspection, an inspector may visually check a product's physical makeup or actually put the products through a series of performance tests. Products may be randomly chosen or entire batches might be examined. Test instruments may be used and reports are usually compiled to identify problems and areas that need improvement.
Manufacturers of goods will usually establish some sort of criteria for their products. This set of criteria is typically the minimum standards that must be met in order for those products to go to market. During a quality control inspection, inspectors compare the finished product against the desired set of characteristics. They also make sure that the product is functioning properly.
For example, inspectors at an auto manufacturer's facility will most likely test a vehicle's lights and warning lamps during a quality control inspection. The inspection may include a visual examination of the car's exterior to ensure that there aren't any nicks or minor damages to the paint job or the tires. Inspectors may look at how the tires are placed on the vehicle and ensure that the size of the nuts and bolts used meets safety requirements. They may also ensure that those tires do not become loose when put under stress.
Some products must undergo a more thorough quality control inspection than others. Products such as food must meet certain government regulations and requirements in order to be deemed sellable. Many times a quality control inspection will involve not only tasting the product, but recording its consistency, temperature, and ingredient composition. Some of these tests may be automated by machines and others are performed manually by inspectors.
During the quality control inspection process, inspectors often identify products that do not meet certain criteria. Some of these products may be able to be fixed if they have minor defects. Others are identified as non-salvageable and discarded. Products that pass a company's quality control standards are usually certified by the inspectors.
Depending on the company's quality control standards, products may be randomly tested during the production process. They may be pulled individually or certain batches may be targeted for inspections. Other quality control techniques involve inspecting products after they have already gone through the production process.
Inspectors will typically make note of their observations by recording the amount of defective products found, the testing methods used, and the measurements obtained during testing. They may participate in a root cause analysis and recommend improvements to plant supervisors in order to reduce the defect rate. Reports are either prepared manually or automatically generated by the instruments used during the testing process.