Quality

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Introduction to Quality Engineering
1.1 QUALITY 1.1.1 DEFINITION OF QUALITY
How is quality defined? It is interesting to observe how its definition varies according to the particular emphasis of quality activities. Juran (1964) defines quality as fitness for use. Crosby (1979) describes quality in terms of conformance to requirements. Deming (1986) says that quality is concerned with thepresent and future needs of the customer. For Feigenbaum (1983) quality is to do with the combined product characteristics of engineering and manufacture that determine the degree to which the product will meet the expectations of the customer. Taguchi (1986) defines quality as the loss a product causes society once it has been shipped, apart from any losses caused by its intrinsic functions.According to ISO 8402 (International Organization for Standardization, 1986), quality is the totality of features and characteristics of a product or service that have a bearing on its ability to satisfy stated or implied needs. Recently, the most widely used definition is that of ISO 9001 (2000). It says that a quality is a characteristic that a product or service must have. For example, products muchbe reliable, useable, and repairable. These are some of the characteristics that a good quality product must have. Similarly, service should be
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ROBUST DESIGN FOR QUALITY ENGINEERING AND SIX SIGMA © World Scientific Publishing Co. Pte. Ltd. http://www.worldscibooks.com/engineering/6655.html

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Robust Design for Quality Engineering and Six Sigma

courteous, efficient, and effective. Theseare some of the characteristics that a good quality service must have. In short, a quality is a desirable characteristic. However, not all qualities are equal. Some are more important than others. The most important qualities are the ones that customers want. These are the qualities that products and services must have. So providing quality products and services is all about meeting customerrequirements. It is all about meeting the needs and expectations of customers. So a quality product or service is one that meets the needs and expectations of customers.

1.1.2 ACTIVITIES OF QUALITY
In the manufacturing industry, activities concerned with quality can be divided into six stages: 1. Product planning: planning for the function, price, life cycle, etc. of the product concerned. 2.Product design: designing the product to have the functions decided in product planning. 3. Process design: designing the manufacturing process to have the functions decided in the product design. 4. Production: the process of actually making the product so that it is of the designed quality. 5. Sales: activities to sell the manufactured product. 6. After-sales service: customer service activitiessuch as maintenance and product services. It is important to note that company-wide activities are necessary to improve quality and productivity at each of the six stages mentioned above. A company needs to build an overall quality system in which all activities interact to produce products of designed quality with minimum costs. Note that there are three different characteristics of quality in anoverall quality system in the manufacturing industry: 1. Quality of design: quality of product planning, product design and process design.

ROBUST DESIGN FOR QUALITY ENGINEERING AND SIX SIGMA © World Scientific Publishing Co. Pte. Ltd. http://www.worldscibooks.com/engineering/6655.html

Introduction to Quality Engineering

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2. Quality of conformance: quality of production. 3. Quality ofservice: quality of sales and after-sales services. Nowadays, these three aspects of quality are equally important in the manufacturing company. If any one of them is not up to the mark, then the overall quality system is unbalanced, and the company will face serious problems. Although these definitions are somewhat different, some common ideas run through them. Quality involves developing...