This is just an Excerpt from a larger document, click here to view the entire document.Determine Customer's Product Needs
Some customers, such as the general public, do not explicitly "specify" what they need in a product, especially reliability. Customers for other products may be very specific and state a numerical reliability requirement. When customers do not explicitly specify their product reliability needs, suppliers have to determine them using a variety of methods.
Determining customer needs is the basis for deriving operational performance reliability requirements and subsequent design requirements. Without designing to those needs, products will not succeed in the marketplace. Customer needs should be determined early in the Concept/Planning (C/P) phase of a product development program, before large investments of time and resources are made. Customer needs are a prerequisite to deriving performance reliability requirements. Performance reliability requirements, in turn, are the basis for the design requirements, which should be defined before starting any design and development. Several approaches may be used to determining the customer needs.
Market Surveys are frequently used to determine what customers want and need in terms of new or improved products. They address desired features and attributes that range from basic functionality to general appearance. There is no better way to understand the needs of customers than to ask them. Surveys can, however, be subject to bias and sampling error. Wellplanned efforts can minimize these effects.
Usually surveys are performed in the C/P phase but alternative forms of surveys can be used when a prototype product is available. In this case, the customers being surveyed may provide real feedback on likes and dislikes in time to introduce product changes prior to full scale development.
Benchmarking (Reference 2) is a proactive process for comparing an organization's products, services, or processes with those of an organization recognized as "best in class" or which is the strongest competition. The purpose is to implement changes in the product, services, or processes needed to meet or beat the competition. By benchmarking its competition or the best-inclass enables a supplier to better understand the needs of the marketplace and to successfully compete in that marketplace. Note that the best-in-class for a process, such as warehousing, or a service, such as maintenance, may not be a direct competitor.
When applied to a product, benchmarking helps an organization understand the levels of performance, including reliability, which the best-in-class are achieving. Ideally, it is conducted prior to product planning and is initiated in the C/P phase of product development. Often, the organization benchmarking a competitor's product will buy a sample of the product and conduct exhaustive testing. The purpose of the testing is to determine the design characteristics of the product including materials used, design margins and tolerances, design approach, and likely manufacturing and assembly methods. The testing will help to understand the operating characteristics and levels of performance. The organization then must decide whether to attempt to match, surpass, or design to some level slightly below that of the best-in-class product. In the case of the first option, the reliability of the best-in-class product becomes the minimum requirement. The last option might be selected if management determines that a product with nearly as good a level of reliability but with a lower cost is an effective way of growing market share.
Benchmarking is useful not only for developing product-level requirements but also for developing requirements at lower levels of indenture. In addition, it may lead to developing requirements for manufacturing and assembly and other aspects of business management that will improve the overall cost and performance of the product.
Environmental Characterization is used to define the operational and environmental stresses that the product will experience when put into use by the customer. Without an understanding of the stresses to be experienced by a product, the statement of reliability objectives, explicitly or implicitly, is meaningless. For example, a product that could have an MTBF of 500 hours in a consumer household may only experience a 200 hour MTBF in an automobile, due to a more stressful environment. The environment should be defined in gross terms very early in the C/P phase. For additional information on environmental effects upon mechanical design see Reference 3.
At a high level, the environment can be characterized in terms such as ground, mobile, airborne, space, etc. This provides a rough indication of the severity ranges of stresses to be experienced. As the design process starts, more detailed information may be necessary. For more severe environments, it may be appropriate to actually use instrumentation to measure the expected stress levels. For example, Time Stress Measurement Devices are available that can be used to measure and record stresses such as temperature, humidity, shock, vibration and power.
Life Cycle Planning (LCP) addresses the product reliability at every phase of the life cycle. It addresses the various phases in developing a mature product all the way to end-of-life considerations, often including product disposal. It should address specific time periods during the product's useful life including shipping, storage (shelf life) and operation. Products need to be planned and designed to preclude failure due to any period of exposure to stress. LCP addresses all phases of the life cycle and both catastrophic and wearout failures. The C/P phase is the time to establish reliability goals and requirements that address the different stress exposures and characteristics during the product's life cycle.
Any time (e.g., shipping, storage, and operation) a product is subjected to stress, there is the potential for failure. Sometimes the stresses of nonoperating periods can be more detrimental than those during operation. From a mechanical standpoint, a consumer television operates in a benign environment but may need extensive protection for shipping. Many products during storage are susceptible to moisture and, therefore, need to be packed with desiccants. All of these factors need to be considered in planning and developing the appropriate reliability goals and requirements for the product.
