Product design quality system element

Production QA is the process whereby the manufacturer adopts a quality system for the manufacture and final inspection of a device. ISO 13485 may also be used as the model in these circumstances, as the design and development elements may be omitted from this standard. The manufacturer must lodge an application with a Notified Body to have his/her system examined. The application must be accompanied by documentation on the quality system and information on any relevant EC type-examined devices. 

The official definition of quality is, the totality of features and characteristics of a product or service that bear upon its ability to satisfy stated or implied needs (ISO 8402). Well-planned design is one of the major contributing factors to achieving quality within a product or service. It is therefore necessary to carefully control critical elements of a company s documentation system with particular reference to each phase of design in order to ensure that the effects on the end products or services are not disastrous and are based on customer requirements. 

Within a company, QC action is directed at three areas raw material control, process control, and finished product control. The approach in setting up a system will be very similar in each case, i.e. design into the operation all the parameters that will bear on the manufacture of quality, followed by a means of establishing that conformance has been achieved. (An important element of this is the continuing revalidation that processes continue to perform as specified.)... 

This equation produces accurate results for a membrane sample or a small element with a low recovery, e.g., 2% or less. However, a practical reverse osmosis system is designed to recover from 25 to 90% of the feedwater. This means that the concentration of the feed varies throughout the membrane system. At 90% recovery, the initial membranes will have a feed which is about 10 times less concentrated than the feed to the final membranes and the quality of the product water will vary incrementally throughout the system. The product water from the first membrane elements will be less concentrated than the product water from the last elements. The product water from the practical reverse osmosis system is combined in the product water manifold and its concentration is usually represented as the average product water concentration. The average product water concentration is determined by the following formula ... 

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