機(jī)構(gòu)設(shè)計(jì)外文翻譯-其他專業(yè)-閱讀頁
2025-02-08 12:26本頁面
【正文】 fication at the development stage of design rather than to leave it to the productiondesign stage, where changes may be made by others, possibly less knowledgeable about all of the functional aspects of the product. At the productiondesign stage ,the primary concern relative to materials should be that they are specified fully ,that they are patible with , and can be processed economically by , existing equipment, and that they are readily available in the needed quantities. As manufacturing progresses , it is inevitable that situations will arise that may require modifications of the materials being used. Experience may reveal that substitution of cheaper materials can be made .In most cases, however, changes are much more costly to make after manufacturing is in progress than before it starts. Good selection during the productiondesign phase will eliminate the necessity for this type of change . The more mon type of change that occurs after manufacturing starts is the result of the availability of new materials. These , of course , present possibilities for cost reduction and improved performance . However, new materials must be evaluate very carefully to make sure that all their characteristics are well established. One should always remember that it is indeed rare that as much is known about the properties and reliability of a new material as about those of an existing one. A large properties of product failure and product – liability cases have resulted from new materials being substituted before their longterm properties were really known . Product liability actions have made it imperative that designers and panies employ the very best procedures in selecting materials. The five most mon faults in material selection have been (a) failure to know and use the latest and best information available about the 外文 原文 63 materials utilized。 (c) the use of materials about which there was insufficient or uncertain data ,particularly as to its longterm properties。 and (e) material selection made by people who are pletely unqualified to do so. An examination of the faults above will lead one to conclude that there is no good reason why they should exist .Consideration of them provides guidance as to how they can be eliminated. While following the very best methods in material selection may not eliminated all productliability claims, the use of proper procedures by designers and industries can greatly reduce their numbers. From the previous discussion, it is apparent that those who select materials should have a broad ,basic understanding of nature and properties of materials and their processing.
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