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2025-08-13 03:28本頁(yè)面
【正文】 may be so nebulous and ill defined that a considerable amount of thought and effort is necessary in ( order to state it dearly as a problem requiring a solution. Here are two 1. Lots of people are killed in airplane accidents.2. In big cities there are too many automobiles on the streets and highways.This second type of design situation is characterized by the fact that neither the need nor the problem to be solved has been identified. Note, too, that the situation may contain not one problem but many.We can classify design, too. For instance, we speak of:1. Clothing design 7. Bridge design2. Interior design 8. Computeraided design3. Highway design 9. Heating system design. 4. Landscape design 10. Machine design5. Building design 11. Engineering design6. Ship design 12. Process designIn fact, there are an endless number, since we can classify design according to the particular article or product or according to the professional field,In contrast to scientific or mathematical problems, design problems have no unique answers。 they happen every day. Suppose that it is desirable from a sales standpoint—for example, in medical laboratory machinery—to create an impression of great strength and durability. Thicker parts assembled with largerthanusual oversize bolts can be used to create a ruggedlooking machine. Sometimes machines and their parts are designed purely from the standpoint of styling and nothing else. These points are made here so that you will not be misled into believing that there is a rational mathematical approach to every design decision.ManufacturingManufacturing is that enterprise concerned with converting raw material into finished products. There are three distinct phases in manufacturing. These phases are as follows: input, processing, and output.The first phase includes all of the elements necessary to create a marketable product. First, there must be a demand or need for the product. The necessary materials must be (available. Also needed are such resources as energy, time, human knowledge, and human skills. Finally, it takes capital to obtain all of the other resources.Input resources are channeled through the various processes in Phase Two. These are the processes used to convert raw materials into finished products. A design is developed. Based on the design, various types of planning are acplished. Plans are put into action through various production processes. The various resources and processes are managed to ensure efficiency and productivity. For example, capital resources must be carefully managed to ensure they are used prudently. Finally, the product in question is marketed.The final phase is the output or finished product. Once the finished product has been purchased it must be transported to users. Depending on the nature of the product, installation and ongoing field support may be required. In addition, with some products, particularly those of a highly plex nature, training is necessary.Materials and Processes in ManufacturingEngineering materials covered herein are divided into two broad categories: metals and nonmetals. Metals are subdivided into ferrous metals, nonferrous metals, highperformance alloys, and powdered metals. Nonmetals are subdivided into plastics, elastomers, posites, and ceramics. Production processes covered herein are divided into several broad categories including forming, forging, casting/molding, .heat treatment^ .fastening joining metrology/quality control, and material removal. Each of these is subdivided into several other processes.Stages in the Development of ManufacturingOver the years, manufacturing processes have gone through four distinct, although overlapping, stages of development. These stages are as follows:Stage 1 Manual Stage 2 Mechanized Stage 3 AutomatedStage 4 IntegratedWhen people first began converting raw materials into finished products, they used manual processes. Everything was acplished using human hands and manually operated tools. This was a very rudimentary form of fully integrated manufacturing. A person identified the need, collected materials, designed a product to meet the need, produced the product, and used it. Everything from start to finish was integrated within the mind of the person who did all the work.Then during the industrial revolution mechanized processes were introduced and humans began using machines to acplish work previously acplished manually. This led to work specialization which, in turn, eliminated the integrated aspect of manu facturing. In this stage of development, manufacturing w
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