Quality Assurance
Disadvantages of quality inspection:
Inspection of the products alone, have proven to be unsatisfactory for the producers. Failing batches have to be destroyed, repaired or sorted out. All expensive mechanism to retain the confidence of the customers. The inspection techniques themselves are not cheap either.
The beginning of quality assurance:
Besides these internal motives, more and more clients are seeking assurance from the supplier that the products are meeting the set specifications. This started during the second world war, when the production of new military equipment and ammunition expanded rapidly, using relatively inexperienced workers to produce them. The allied forces were seeking guarantees that their equipment would operate under all circumstances and that the ammunition was reliable.
Much later in 1970 the NATO formulated these requirements in contract clauses. Suppliers had to provide plausible evidence that its products were manufactured under controlled circumstances and that the product prior delivery had been tested.
Thus quality management moved from product inspection to production control. The initial assumption was that control of the production process would eliminate all possible causes of failures of the products and therefore the products would meet the specifications.
Thus quality management moved from product inspection to production control. The initial assumption was that control of the production process would eliminate all possible causes of failures of the products and therefore the products would meet the specifications.
Eliminating causes of variation:
In reality the control of the production processes focuses on eliminating all causes of variation. Thus by controlling the variations of all inputs and the production processes an attempt is made to control the variations of the products’/services’ quality.
Assignable causes:
The production characteristics vary because the equipment wears out but more importantly everybody operates differently. Over time, routineoperating teams will develop an attitude to deliver the minimum acceptable, which they wrongly consider as the most efficient operation. As a result the quality of the process reduces and eventually the quality of the products. The management can easily correct these so-called assignable causes of variations.
Common causes:
However there are also common causes of variation. These causes are inherent of the production process or their inputs. To get rid of these causes the management has to change the production process or choose for other inputs.
Standardisation Quality:
Assurance focuses on controlling the assignable causes of variation through standardisation and is therefore a way of coordinating efforts between different operating and support units. The production processes are described and formalised in procedures. These processes are closely monitored and failures are described. When the production process does not perform as described in the procedure corrective actions are required. The monitoring often includes so-called control charts.
Identify causes:
Besides earlier mentioned objectives, the principal goal of the control chart is to separate assignable causes of variation from common causes of variation.
The chart helps in preventing two types of errors:
The first type of error involves the belief that an observed value represents assignable cause variation when in fact it is due to the common cause variation of the process. The second type of error involves treating assignable cause variation as if it were common cause variation and thus not taking immediate corrective action when it is necessary.
Customer satisfaction:
However processes that are in control are not a guarantee that the customers are satisfied about the product or service. Too many dissatisfied customers often lead to product and production process changes. There are many ways to analyse customer satisfaction.
Quality assurance techniques in projects:
Quality assurance techniques have been successfully applied on all sorts of routine operations, like mass production. It has been recognised that it is far more difficult to apply the technique on design or project operations. Project operations are characterised by high uncertainty of the product, production process and required inputs. Nonetheless an important task of project managers is to ensure the quality of the project outputs. This often implies setting quality standards for the different project activities and monitoring the performance. Actions very similar to quality assurance actions for routine operations. The mere difference is that it is difficult to audit the project and to obtain certificates from external organisations. Furthermore project managers have to build in potential variations to explore unique options to address the customer demands.
