Quality assurance means assuring quality in the product so that a customer can buy it with confidence and use it with confidence and satisfaction. To be able to buy with confidence, a customer must have a sense of trust in a particular product from a particular company that has a record of having reliable products for a long time. To build up this kind of trust, it is necessary to ensure quality of design and to make certain that the product is fully functional in the way that the customer expects. Quality assurance is almost like a contract entered into by the producer and its customer. In order to provide true quality assurance, top executives must establish firm policies that will encompass all of the following divisions: research, planning, design, production, marketing, after sales service and customer service.
Quality assurance is a set of activities intended to establish confidence that quality requirements will be met. It is one part of quality management. The quality assurance function should be a cross functional activity in which all functional departments play a specific role in planning for and analysing quality.
Quality control is considered part of the quality functions. It is a regulatory process through which each department measures the actual quality performance, compares it with the standard, and acts on the difference.
Inspection is an appraisal activity that compares products to applicable standards. In a modern quality management approach, everyone in the organization is an inspector and is responsible for inspecting the work they perform. The best inspection is conducted at the source, at the time the output is made, and by the individual who makes it.
We need to consider the three different aspects of quality assurance:
- inspection-oriented quality assurance
- process control-oriented quality assurance
- quality assurance with emphasis on new product development.
Inspection-oriented quality assurance
Quality assurance started with doing inspection well. This approach is still being practised in a lot of countries as many people still consider that inspection equals quality assurance. This may stem from the basic assumption that the work and workers must be supervised very strictly. To accomplish this, the inspection department is made independent and its authority is enhanced. In short, the basic emphasis is on strengthening inspection in order to bring about quality assurance. Therefore, the ratio of inspectors to line workers is very high. This approach, however, raises several other points, or some might say problems in managing quality.
- Problem 1
The first problem is that inspectors are unnecessary personnel who reduce the overall productivity of a company. They are not making anything. Inspection is necessary because defects and defectives exist. If defects and defectives disappear, inspectors become unnecessary.
- Problem 2
The second problem is that responsibility for quality assurance rests with the producers. Needless to say, this concept is for the benefits of consumers, but it has been further applied within a company. The producer, the production department, assumes responsibility for quality assurance, and the inspection department does not. The latter's function is to check the products from the point of view of consumers or of company managers. The production department, being duly educated and trained, will control its process itself and self-inspect its own products before sending them off to the next process. It thus assures quality.
- Problem 3
The third problem deals with the issue of information feedback from the inspection department to the production department. This process takes time. If the line worker who is responsible for a particular product is given the task of self-inspection, feedback is instantaneous and action can be taken immediately. The latter approach ensures a sharp reduction in the number of defectives.
- Problem 4
The fourth problem deals with the question of production speed. When the speed accelerates, workers cannot inspect. Thus automated inspection must be considered.
- Problem 5
The fifth problem concerns the application of the statistical sampling method. The method may designate an acceptable quality level (AQL; the lowest quality acceptable, details will be discussed in Unit 3) at 1% or at 0.5%. This is unsatisfactory for companies that seek higher quality levels, such as those seeking a defect rate of 0.01% or those seeking ppm (parts per million) control (at a defect rate of one one-millionth).
- Problem 6
The sixth problem deals with those many items whose quality cannot be assured through inspection alone. The quality of many complicated assembled commodities and materials cannot be known until used. For example, components embedded in a sub-assembly. When a company seeks control based on a destructibility test, a rigorous performance test, or reliability test, inspection is often uneconomical and cannot necessarily assure quality by itself.
Lastly, it must be noted that defects can indeed be uncovered through inspection, without the end result measuring up to true quality assurance. When defects are found, the only action the manufacturer can take is that of making adjustments, reworking the product, or consigning it to scrap.
Process control-oriented quality assurance
This approach, so called 'quality must be built into each process,' emphasizes process control. The process capabilities are studied and it is made certain that each product should meet quality standards through control of the production process. It relies on the control of the process rather than the inspection of products by the inspection department to perform the task of quality assurance. Everyone in the process has to be involved. The process control concept can be further extended to cover suppliers and subcontractors.
However, quality assurance can not be achieved by means of process control alone. Problems can occur in the designing or development process, which obviously can not be solved by the production or inspection department. And no matter how hard a department engages in process control, if the selection of materials are wrong, nothing can be accomplished. Therefore, while process control remains an important concern and must continue to be practised, it has been discovered that it is indispensable to have quality assurance, which begins at the stage where new products are developed.
Quality assurance with emphasis on new product development.
This approach emphasizes that at each step of the way from planning for new products to after-sales service, evaluation must be tightly conducted and quality assured. These steps include new product planning, design, prototype making, testing, subcontracting, purchasing, process design, trial production, production, marketing, distribution and after-sales service. Prior to entering the stage of production, quality analysis has to be adequately performed, including testing for reliability under various conditions. Quality assurance is thus built into the entire product and processes as well. Since quality assurance is conducted for new product development, full participation of all departments in the company in realizing quality control and quality assurance is essential.
These departments include research, planning, design, testing, purchasing, subcontracting, production engineering, production, inspection, marketing and after-sales service. Starting with those people who engage in market research and planning and ending with those employees who engage in sales and after-sales service, everyone and every department in the company must participate.
Based on the above discussion, quality assurance does not completely negate the importance of inspection. It must be clear, however, that no matter how closely a company may inspect its products, there will always be some inspection misses and some defectives will still be shipped. It is uneconomical to rely on inspection. This is the reason for shifting emphasis to process control. However, good process control without proper new product development is meaningless. We need to have sound new product development then we can have good quality with proper process control.
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