Introduction to Machine Design
Machine design is the application of science and technology to devi new Or improved products for the purpo of satisfying human needs．It is a vast field of engineering technology which not only concerns itlf with the original conception of the product in terms of its size，shape and construction details，but also considers the various factors involved in the manufacture，marketing and u of the product．
People who perform the various functions of machine design are typically called designers，or design engineers．Machine design is basically a creative activity．However，in addition to being innovative，a design engineer must also have a solid background in the areas of mechanical drawing，kinematics，dynamics, materials engineering, strength of materials and manufacturing process.祈使句的结构
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As stated previously，the purpo of machine design is to produce a product which will rve a need for man．Inventions，discoveries and scientific knowledge by themlves do not necessarily benefit people；only if they ale incorporated into a designed product will a b万能评价
enefit be derived．It should be recognized，therefore，that a human need must be identified before a particular product is designed．
Machine design should be considered to be an opportunity to u innovative talents to envision a design of a product，to analyze the system and then make sound judgments on how the product is to be manufactured．It is important to understand the fundamentals of engineering rather than memorize mere facts and equations．There are no facts or equations which alone can be
ud to provide all the correct decisions required to produce a good design．On the other hand，any calculations made must be done with the utmost care and precision．For example，if a decimal point is misplaced，an otherwi acceptable design may not function．
Good designs require trying new ideas and being willing to take a certain amount of risk，knowing that if the new idea does not work the existing method call be reinstated．Thus a designer must have patience，since there is no assurance of success for the time
and effort expended．Creating a completely new design generally requires that many old and well．established methods be thrust aside．This is not easy since many people cling to familiar ideas，techniques and attitudes．A design engineer should constantly arch for ways to improve all existing product and must decide what old，proven concepts should be ud and what new，untried ideas should be incorporated．
New designs generally have “bugs” or unforeen problems which must be worked out before the superior characteristics of the new designs can be enjoyed. Thus there is a chance for a superior product．but only at higher risk．It should be emphasized that，if a design does not warrant radical new methods，such methods should not be applied merely for the sake of change．
During the beginning stages of design，creativity should be allowed to flourish without a great number of constraints．Even though many impractical ideas may ari，it is usually easy to eliminate them in the early stages of design before firm details are required by manufacturing．In this way，innovative ideas are not inhibited．Quite often，
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i的笔顺more than one design is developed，up to the point where they call be compared against each other．It is entirely possible that the design which is ultimately accepted will u ideas existing in one of the rejected designs that did not show as much overall promi．
Psychologists frequently talk about trying to fit people to the machines they operate．It is esntially the responsibility of the design engineer to strive to fit machines to people．This is not an easy task，since there is really no average person for which certain operating dimensions and procedures are optimum．
Another important point which should be recognized is that a design engineer must be able to communicate ideas to other people if they ale to be incorporated．Initially，the designer must communicate a preliminary design to get management approval．This is usually done by verbal discussions in conjunction with drawing layouts and written material．To communicate effectively，the following questions must be answered：
(1Does the design really rve a human need?
(2Will it be competitive with existing products of rival companies?
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(3Is it economical to produce?
(4Can it be readily maintained?
(5Will it ll and make a profit?
微信怎么撤回Only time will provide the true answers to the preceding questions，but the product should be designed，manufactured and marketed only with initial affirmative answers．The design engineer also must communicate the finalized design to manufacturing through the u of detail and asmbly drawings．
