机械类外文文献翻译(中英文翻译).doc

《机械类外文文献翻译(中英文翻译).doc》由会员分享，可在线阅读，更多相关《机械类外文文献翻译(中英文翻译).doc（6页珍藏版）》请在淘文阁 - 分享文档赚钱的网站上搜索。

1、机械类外文文献翻译(中英文翻译) 英文原文 Mechanical Design and Manufacturing Processes Mechanical design is the application of science and technology to devise new or improved products for the purpose of satisfying human needs. It is a vast field of engineering technology which not only concerns itself with the origin

2、al 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 use of the product. People who perform the various functions of mechanical design are typically called designers, or design engineers.

3、Mechanical 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 processes. As stated previously,

4、the purpose of mechanical design is to produce a product which will serve a need for man. Inventions, discoveries and scientific knowledge by themselves do not necessarily benefit people; only if they are incorporated into a designed product will a benefit be derived. It should be recognized, theref

5、ore, that a human need must be identified before a particular product is designed. Mechanical design should be considered to be an opportunity to use 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

6、 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 used to provide all the correct decisions required to produce a good design.On the other hand, any calculations made must be done with the utm

7、ost care and precision. For example, if a decimal point is misplaced, an otherwise 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 can be reinstated. Thus a des

8、igner 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 d

9、esign engineer should constantly search for ways to improve an existing product and must decide what old, proven concepts should be used and what new, untried ideas should be incorporated. New designs generally have bugs or unforeseen problems which must be worked out before the superior characteris

10、tics 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, cre

11、ativity should be allowed to flourish without a great number of constraints. Even though many impractical ideas may arise, 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 ofte

12、n, more than one design is developed, up to the point where they can be compared against each other. It is entirely possible that the design which is ultimately accepted will use ideas existing in one of the rejected designs that did not show as much overall promise. Psychologists frequently talk ab

13、out trying to fit people to the machines they operate. It is essentially 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 importa

14、nt point which should be recognized is that a design engineer must be able to communicate ideas to other people if they are to be incorporated. Communicating the design to others is the final, vital step in the design process. Undoubtedly many great designs, inventions, and creative works have been

15、lost to mankind simply because the originators were unable or unwilling to explain their accomplishments to others. Presentation is a selling job. The engineer, when presenting a new solution to administrative, management, or supervisory persons, is attempting to sell or to prove to them that this s

16、olution is a better one. Unless this can be done successfully, the time and effort spent on obtaining the solution have been largely wasted. Basically, there are only three means of communication available to us. These are the written, the oral, and the graphical forms. Therefore the successful engi

17、neer will be technically competent and versatile in all three forms of communication. A technically competent person who lacks ability in any one of these forms is severely handicapped. If ability in all three forms is lacking, no one will ever know how competent that person is! The competent engine

18、er should not be afraid of the possibility of not succeeding in a presentation. In fact, occasional failure should be expected because failure or criticism seems to accompany every really creative idea. There is a great deal to be learned from a failure, and the greatest gains are obtained by those

19、willing to risk defeat. In the final analysis, the real failure would lie in deciding not to make the presentation at all. To communicate effectively, the following questions must be answered: (1) Does the design really serve a human need? (2) Will it be competitive with existing products of rival c

20、ompanies? (3) Is it economical to produce? (4) Can it be readily maintained? (5) Will it sell and make a profit? 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 enginee

21、r also must communicate the finalized design to manufacturing through the use of detail and assembly drawings. Quite often, a problem will occur during the manufacturing cycle 3. It may be that a change is required in the dimensioning or tolerancing of a part so that it can be more readily produced.

22、 This fails in the category of engineering changes which must be approved by the design engineer so that the product function will not be adversely affected. In other cases, a deficiency in the design may appear during assembly or testing just prior to shipping. These realities simply bear out the f

23、act that design is a living process. There is always a better way to do it and the designer should constantly strive towards finding that better way. Designing starts with a need, real or imagined. Existing apparatus may need improvements in durability, efficiently, weight, speed, or cost. New appar

24、atus may be needed to perform a function previously done by men, such as computation, assembly, or servicing. With the objective wholly or partly defined, the next step in design is the conception of mechanisms and their arrangements that will perform the needed functions.For this, freehand sketchin

25、g is of great value, not only as a record of ones thoughts and as an aid in discussion with others, but particularly for communication with ones own mind, as a stimulant for creative ideas. When the general shape and a few dimensions of the several components become apparent, analysis can begin in e

26、arnest. The analysis will have as its objective satisfactory or superior performance, plus safety and durability with minimum weight, and a competitive east. Optimum proportions and dimensions will be sought for each critically loaded section, together with a balance between the strength of the seve

27、ral components. Materials and their treatment will be chosen. These important objectives can be attained only by analysis based upon the principles of mechanics, such as those of statics for reaction forces and for the optimum utilization of friction; of dynamics for inertia, acceleration, and energy; of elasticity and strength of materials for stress