Through routine inspection practices, manufacturing companies worldwide are managing to control the quality of their products offered to their customers.
By “inspection” it is usually meant that, at certain stages in the course of production, a comparison is made between what has actually been produced and what should have been produced. The standard of reference may be a specification, drawing or a visual quality standard. The check made must be appropriate to the job and must be made with suitable measuring instruments. Inspectors should not waste time checking things that do not matter or fail to do a check that is important. Things that are unlikely to go wrong need little checking and those which are difficult to hold within limits will need a considerable amount of attention.
It is a misconception that the Inspector alone is responsible for quality. Quality results from a combination of the quality of the original designs, the methods used, equipment and materials used and the skill and care of the operator. In spite of these, if the job is still wrong, no amount of inspection will put it right.
According to production flow, the inspection may be divided into: Incoming inspection, In-process inspection and Final inspection. Incoming inspection concerns goods upon delivery from vendors and/or suppliers. It consists of inspection of raw materials, components, sub-assemblies and so on. The aim of incoming inspection is to prevent goods that do not fulfill the quality requirements from entering the production process.
In-process inspection aims to prevent products of unacceptable quality from being manufactured. It provides data for making decisions on the product (accept or rework or reject), as well as on the process (run or stop).
Final inspection and/or testing is done after manufacture has been completed, with the object of making sure that the goods concerned are satisfactory for dispatch to the customer or maybe to another department for the next operation.
Based on the product specifications, inspection instructions are prepared that lay down the details of the tests to be carried out, the measuring instruments or test equipment to be used and the criteria for deciding acceptance of the product with respect to each characteristic. Inspection instructions should also include details of the sampling plan such as size of sample and the criteria of acceptance to be followed. Measuring instruments or test equipment used for inspection should be calibrated periodically to verify their accuracy.
It is necessary to exercise suitable control over the movement of the product through the inspection area in order to avoid a mix-up of accepted and rejected products. Ways to exercise such control include:
Provision of clear labels (preferably of different colours) for products awaiting inspection, accepted products, rejected products, products on hold awaiting the results of tests and/or inspection and so on;
For further information, please contact the GNBS on telephone numbers: 219-0062, 219-0065, 219-066.
