机械设计过程外文文献翻译、中英翻译、外文翻译

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The Design of Machinery Process

Design Invention Creativity

These are all familiar terms but may mean different things to different people. These terms can encompass a wide range of activities from styling the newest look in clothing, to creating impressive architecture, to engineering a machine for the manufacture of facial tissues. Engineering design, which we are concerned with here, embodies all three of these activities as well as many others. The word design is derived from the Latin designare,which means “to designate, or mark out.” Webster’s gives several definitions, the most applicable being “to outline, plot, or plan, as action or work…to conceive,invent-contrive.” Engineering design has been define d as “...the process of applying the various techniques and scientific principles for the purpose of defining a device,a process or a system in sufficient detail to permit its realization...Design may be simple or enormously complex, easy or difficult, mathematical or nonmathematical; it may involve a trivial problem or one of great importance.” Design is a universal constituent of engineering practice. But the complexity of engineering subjects usually requires that the student be served with a collection of structured, set-piece problems designed to elucidate a particular concept or concepts related to the particular topic. These textbook problems typically take the form of “given A, B, C, and D, find E.” Unfortunately,real-life engineering problems are almost never so structured. Read design problems more often take the form of “What we need is a framus to stuff this widget into that hole within the time allocated to the transfer of this other gizmo.” The new engineering graduate will search in vain among his or her textbooks for much guidance to solve such a problem.This unstructured problem statement usually leads to what is commonly called “blank paper syndrome.” Engineers often find themselves staring at a blank sheet of paper pondering how to begin solving such an ill-defined problem.

Much of engineering education deals with topics of analysis, which means to decompose,to take apart, to resolve into its constituent parts. This is quite necessary. The engineer must know how to analyze systems of various types, mechanical, electrical, thermal or fluid.Analysis requires a thorough understanding of both the appropriate mathematical techniques and the fundamental physics of the system’s function. But, before any system can be analyzed, it must exist, and a blank sheet of paper provides little substance for analysis. Thus the first step in any engineering design exercise is that of synthesis, which means putting together.

The design engineer, in practice, regardless of discipline, continuously faces the challenge of structuring the unstructured problem. Inevitably, the problem as posed to the engineer is ill-defined and incomplete. Before any attempt can be made to analyze the

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Much research has been devoted to the definition of various “design processes”intended to provide means to structure the unstructured problem and lead to a viable solution. Some of these processes present dozens of steps, others only a few. The one presented in table 1-1 contains 10 steps and has, in the author’s experience, proven successful in over 30 years of

practice in engineering design.

ITERATION Before discussing each of these steps in detail it is necessary to point out that this is not a process in which one proceeds from step one through ten in a linear fashion. Rather it is, by its nature, an iterative process in which progress is made haltingly, two steps forward and one step back. It is inherently circular. To iterate means to repeat, to return to a previous state. If, for example, your apparently great idea,upon analysis, turns out to violate the second law of thermodynamics, you can return to the ideation step and get a better idea! Or, if necessary, you can return to an earlier step in the process, perhaps the background research, and learn more about the problem.With the understanding that the actual execution of the process involves iteration, for simplicity, we will now discuss each step in the order listed in table 1-1.

Identification of Need

This first step is often done for you by someone, boss or client, saying “What we need is...” Typically this statement will be brief and lacking in detail. It will fall far short of providing you with a structured problem statement. For example, the problem statement might be “We need a better lawn mower.”

Background research

This is the most important phase in the process, and is unfortunately often the most neglected. The term research, used in this context, should not conjure up visions of white-coated scientists mixing concoctions in test tubes. Rather this is research of a more mundane sort, gathering background information on the relevant physics, chemistry, or other

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Goal Statement

Once the background of the problem area as originally stated is fully understood, you will be ready to recast that problem into a more coherent goal statement. This new problem statement should have three characteristics. It should be concise, be general, and be uncolored by any terms which predict a solution. It should be couched in terms of functional visualization, meaning to visualize its function, rather than any particular embodiment. For example, if the origina l statement of need was “Design a Better Lawn Mower,” after research into the myriad of ways to cut grass that have been devised over the ages, the wise designer might restate the goal as “Design a Means to Shorten Grass.” The original problem statement has a built-in trap in the form of the colored words “lawn mower.” For most people, this phrase will conjure up a vision of something with whirring blades and a noisy engine. For the ideation phase to be most successful, it is necessary to avoid such images and to state the problem generally, clearly, and concisely. As an exercise, list 10 ways to shorten grass. Most of them would not occur to you had you been asked for 10 better lawn mower designs. You should use functional visualization to avoid unnecessarily limiting your creativity!

Performance Specifications

When the background is understood, and the goal clearly stated, you are ready to formulate a set of performance specifications. These should not be design specifications. The difference is that performance specifications define what the system must do, while design specifications define how it must do it. At this stage of the design process it is unwise to attempt to specify how the goal is to be accomplished. That is left for the ideation phase. The purpose of the performance specifications is to carefully define and constrain the problem so

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TABLE 1-2 Performance Specifications

1 Device to have self-contained power supply.

2 Device to be corrosion resistant.

3 Device to cost less than ＄100.00.

4 Device to emit < 80 dB sound intensity at 50 feet.

5 Device to shorten 1/4 acre of grass per hour.

6 etc...etc.

Note that these specifications constrain the design without overly restricting the engineer’s design freedom. It would be inappropriate to require a gasoline engine for specification 1, since other possibilities exist which will provide the desired mobility. Likewise, to demand stainless steel for all components in specification 2 would be unwise, since corrosion resistance can be obtained by other, less-expensive means. In short, the performance specifications serve to define the problem in as complete and as general a manner as possible, and they serve as a contractual definition of what is to be accomplished. The finished design can be tested for compliance with the specifications.

Ideation and Invention

This step is full of both fun and frustration. This phase is potentially the most satisfying to most designers, but it is also the most difficult. A great deal of research has been done to explore the phenomenon of “creativity.” It is, most D, a common human trait. It is certainly exhibited to a very high degree by all young children. The rate and degree of development that occurs in the human from birth through the first few years of life certainly requires some innate creativity. Some have claimed that our methods of Western education tend to stifle children’s natural creativity by encouraging conformity and restricting individuality. From “coloring within the lines” in kindergarten to imitating the textbook’s writing patterns in later grades, individuality is suppressed in favor of a socializing conformity. This is perhaps necessary to avoid anarchy but probably does have the effect of reducing the individual’s ability to think creatively. Some claim that creativity can be taught, some that it is only inherited, No hard evidence exists for either theory. It is probably true that one’s lost or suppressed creativity can be rekindled. Other studies suggest that most everyone underutilizes his or her potential creative abilities. You can enhance your creativity through various techniques.

C RENATIVE P ROCESS Many techniques have been developed to enhance or inspire creative problem solving. In fact, just as design processes have been defined, so has the creative process shown in Table 1-3 . This creative process can be thought of as a subset of the design process and to exist within it. The ideation and invention step can thus be broken

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TABLE 1-3 The Creative Process

5a Idea Generation 5b Frustration

5c Incubation 5d Eureka!

I DEA G ENERATION is the most difficult of these steps. Even very creative people have difficult in inventing “on demand.” Many techniques have been suggested to improve the yield of ideas. The most important technique is that of deferred judgment, which means that your criticality should be temporarily suspended. Do not try to judge the quality of your ideas at this stage. That will be taken care of later, in the analysis phase. The goal here is to obtain as large a quantity of potential designs as possible. Even superficially ridiculous suggestions should be welcomed, as they may trigger new insights and suggest other more realistic and practical solutions.

B RAINSTORMING is a technique for which some claim great success in generating creative solutions. This technique requires a group, preferably 6 to 15 people, and attempts to circumvent the largest barrier to creativity, which is fear of ridicule. Most people, when in a group, will not suggest their real thoughts on a subject, for fear of being laughed at. Brainstorming’s rules require that no one is allowed to make fun of or criticize anyone’s suggestions, no matter how ridiculous. One participant acts as “scribe” and is duty bound to record all suggestions, no matter how apparently silly. When done properly, this technique can be fun and can sometimes result in a “feeding frenzy” of ideas which build upon each other. Large quantities of ideas can be generated in a short time. Judgment on their quality is deferred to a later time.

When working alone, other techniques are necessary. Analogies and inversion are often useful. Attempt to draw analogies between the problem at hand and other physical contexts. If it is a mechanical problem, convert it by analogy to a fluid or electrical one. Inversion turns the problem inside out. For example, consider what you want moved to be stationary and vice versa. Insights often follow. Another useful aid to creativity is the use of synonyms. Define the action verb in the problem statement, and then list as many synonyms for that verb as possible. For example:

Problem statement: Move this object from point A to point B.

The action verb is “move.”Some synonyms are push, pull, slip, shove, throw, eject, jump, and spill.

By whatever means, the aim in this ideation step is to generate a large number of ideas without particular regard to quality. But, at some point, your “mental well” will go dry.

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In “Unlocking Human Creativity”wallen describes three requirements for creative insight:

﹒Fascination with a problem.

﹒Saturation with the facts, technical ideas, data, and the background of the problem.

﹒A period of reorganization.

The first of these provides the motivation to solve the problem. The second is the background research step described above. The period of reorganization refers to the frustration phase when your subconscious works on the problem. Wallen reports that testimony from creative people tells us that in this period of reorganization they have no conscious concern with the particular problem and that the moment of insight frequently appears in the midst of relaxation or sleep. So to enhance your creativity, saturate yourself in the problem and related background material. Then relax and let your subconscious do the hard work!

Analysis

Once you are at this stage, you have structured the problem, at least temporarily, and can now apply more sophisticated analysis techniques to examine the performance of the design in the analysis phase of the design process. Further iteration will be required as problems are discovered from the analysis. Repetition of as many earlier steps in the design process as necessary must be done to ensure the success of the design.

Selection

When the technical analysis indicates that you have some potentially viable designs, the best one available must be selected for detailed design, prototyping, and testing.The selection process usually involves a comparative analysis of the available design solutions. A decision matrix sometimes helps to identify the best solution by forcing you to consider a variety of factors in a systematic way. A decision matrix for our better grass shortener is shown in Figure 1-2. Each design occupies a row in the matrix. The columns are assigned categories in which the designs are to be judged, such as cost, ease of use, efficiency, performance, reliability, and

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This step usually includes the creation of a complete set of assembly and detail drawings or computer-aided design (CAD) part files, for each and every part used in the design. Each

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Prototyping and Testing

M ODELS Ultimately, one cannot be sure of the correctness or viability of any design until it is built and tested. This usually involves the construction of a prototype physical model. A mathematical model, while very useful, can never be as complete and accurate a representation of the actual physical system as a physical model, due to the need to make simplifying assumptions. Prototypes are often very expensive but may be the most economical way to prove a design, short of building the actual, full-scale device. Prototypes can take many forms, from working scale models to full-size, but simplified, representations of the concept. Scale models introduce their own complications in regard to proper scaling of the physical parameters. For example, volume of material varies as the cube of linear dimensions, but surface area varies as the square. Heat transfer to the environment may be proportional to surface area, while heat generation may be proportional to volume. So linear scaling of a system, either up or down, may lead to behavior different from that of the full-scale system. One must exercise caution in scaling physical models. You will find as you begin to design linkage mechanisms that a simple cardboard model of your chosen link lengths, coupled together with thumbtacks for pivots, will tell you a great deal about the quality and character of the mechanism’s motions. You should get into the habit of making such simple articulated models for all your linkage designs.

T ESTING of the model or prototype may range from simply actuating it and observing its function to attaching extensive instrumentation to accurately measure displacements, velocities, accelerations, forces, temperatures, and other parameters. Tests may need to be done under controlled environmental conditions such as high or low temperature or humidity. The microcomputer has made it possible to measure many phenomena more accurately and inexpensively than could be done before.

Production

Finally, with enough time, money, and perseverance, the design will be ready for production. This might consist of the manufacture of a single final version of the design, but more likely will mean making thousands or even millions of your widget. The danger, expense, and embarrassment of finding flaws in your design after making large quantities of defective devices should inspire you to use the greatest care in the earlier steps of the design process to ensure that it is properly engineered.

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The design process is widely used in engineering. Engineering is usually defined in terms of what an engineer does, but engineering can also be defined in terms of how the engineer does what he or she does. Engineering is as much a method, an approach, a process, a state of mind for problem solving, as it is an activity. The engineering approach is that of thoroughness, attention to detail, and consideration of all the possibilities. While it may seem a contradiction in terms to emphasize “attention to detail”while extolling the virtues of open-minded, freewheeling, creative thinking, it is not. The two activities are not only compatible, they are symbiotic. It ultimately does no good to have creative, original ideas if you do not, or cannot, carry out the execution of those ideas and “reduce them to practice.”To do this you must discipline yourself to suffer the nitty-gritty, nettlesome, tiresome details which are so necessary to the completion of any one phase of the creative design process. For example, to do a creditable job in the design of anything, you must completely define the problem. If you leave out some detail of the problem definition, you will end up solving the wrong problem. Likewise, you must thoroughly research the background information relevant to the problem. You must exhaustively pursue conceptual potential solutions to your problem. You must then extensively pursue conceptual potential solutions to your problem. You must then extensively analyze these concepts for validity. And, finally, you must detail your chosen design down to the last nut and bolt to be confident it will work. If you wish to be a good designer and engineer, you must discipline yourself to do things thoroughly and in a logical, orderly manner, even while thinking great creative thoughts and iterating to a solution. Both attributes, creativity and attention to detail, are necessary for success in engineering design.

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机械设计过程

设计、发明与创造

这几个术语都是大家熟悉的。但对不同的人又有不同的含义。这几个术语也包括很宽的行业范围，从设计符合时代潮流的最新款式服装到创作令人难以忘怀的建筑物，直至用于面巾纸制作的工业机器。这里所指的“工程设计”既包括上述三个行业，也可以包括许多其他行业。“design”一词是拉丁语“designare”的派生词，其意思是“指明或策划”。Webster给出了几个定义，其中最适当的是“以画草图、曲线或作计划安排活动或工作……去构想、发明、创新”。工程设计可定义为“……为了把一个装置、工艺或系统制定得十分详细，一直可以参照实施的目的，各种技术和科学原理的利用过程。……设计可以是简单的或是非常复杂的，容易的或是很难的，粗糙的或是精确的，它可以是一个无关紧要的问题，也可以是一个极其重要的问题”。设计是工程实践的一个普通的组成要素。但是，工程问题复杂性习惯地要求学生用一堆结构式、事先精心设置好的问题来阐述特定的概念或与特定问题有关的概念。这类典型的教科书式地阐述问题所采取的形式是“已知A、B、C、D，求E”。可惜的是，现实的工程问题几乎从不是这种机构式问题。实际设计问题通常采取的形式是“我们需要一种工具，用于把该种小产品装入孔内，再在规定时间内把另一种小件产品传送过来。”新毕业的工科学生要想从教科书中寻找解决这类问题的提示是徒劳的，这类非结构式问题的提法称为“空白纸集合”。工程师常会找出自己的空白纸来考虑如何解决这类不确定性的问题。

许多工程教育在处理分析专题时，常把它理解为分解、区别、还原到它的组成部分中，这是十分重要的。一名工程师必须懂得如何分析机械、电子、热力或流体的各类系统。通过分析，要求完全弄清适用的数学方法和系统功能的基本物理过程。但是，在进行任何一种系统的分析之前，该系统必须是存在的，提出分析的内容并把它列在空白的表格纸上。因此，任何工程设计培养的第一步应是练习综合，这就是说学会对比研究、综合推断。

实际上，不论是哪类学科的设计工程师都会不断地面临结构式和非结构式问题的困惑，因而它所提出的问题也必然是不完全和不充分的。在进行任何一种分析之前，必须用工程方法先仔细地定义设计问题，以确保所得的每个解都是求解实际问题的结果。在实际中也有这样的一些例子，虽然存在一些好的解，但由于求解的是错误问题（与委托人提出的问题有区别）而被弃用。

一些人专心致力于确定“设计过程”的研究，想为求解结构式和非结构式问题提出方法，并得出其可行解。在这类研究中，有些人把设计过程归纳为几个步骤或几十个步骤，但根据作者30余年的工程设计实践的成功经验，一个设计过程至少应包含10个步骤，见表1-1。

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表 1-1 设计过程

1 需求识别

2 背景调查

3 目标陈述

4 性能技术条件

5 构思与发明

6 分析

7 选择

8 详细设计

9 样机与实验 10 生产

反复在详细讨论每个设计步骤之前，必须指出的一点是，每一次的设计过程都不是按部就班地进行，不是从第一步笔直做到第十步。更确切地说，设计从本质上说是一个反复的过程，而且每一次反复都有所前进和提高。反复意味着重复，返回到前一步。例如，如果当你的重大构思经过分析，结果证明是违背热力学第二定律的，则须发回到形成概念那一步，以获得一个更好的构思！火者，如有必要则返回到设计过程的最初几步，甚至返回到背景调查，认识问题的更多方面。以设计过程的实际实施包括反复为前提，下面简要地讨论表1-1中所列的每一个设计步骤。

需求识别

需求识别是设计师根据主管或委托人说的“我们需求什么……”所要做的第一步工作。由于需求的提法往往是简短而不详细的，而且是非常不具体的，例如，“我们需要一台较好的割草机”。

背景调查

背景调查是设计过程中很重要的一个阶段，但遗憾的是经常被忽视。设计过程中的调查，不应该像穿白外套的科学家凭想象地在试管内搅拌配制品那样，更确切地说，是对设计问题进行调查研究，收集于该问题有关的物理、化学或其他方面的背景信息。如果该类问题（或相类似问题）以前曾求解过，则应把它找出来，不要重蹈覆辙。如果很幸运地在市面上找到了一个县城求解结果，则应把它购买进来，总要比自己设计经济些。绝大多数不是这种情况，但是通过调查研究现存的、有关的相似工艺和产品的“技术”，你可以学到很多与要求借问题有关的东西。有关信息可以从相应的专利或技术文献以及通过全球网查询中得到。很明显，如果找到了现成的解或是一个还有效的专利，那么就可以有几种选择：购买现成解的专利、自行设计但不与专利冲突，或者终止项目。为了避免对不正确问题策划一个重大的解而造成浪费，对背景调查和设计过程的准备，多用一些时间和精力是非常必要的。经验不多的工程师都不太重视这个阶段，想跳过这个阶段，并很快地进入设计过程的构思和发明，这是必须避免的！应该告诫自己在尚未做好充分准备之前，就不要着手去解决问题。

目标陈述

一旦完全明白了原先表述的设计问题的背景，就应该把设计问题改写为更明晰的目标陈述。对一个新设计问题，目标陈述应有三个特征：一般应是简明的：应该不经任何措辞修饰，并对其问题有一个预定的解；应该根据它的功能给出形象化描述（即使它的功能具体化）。例如，原先对需求说的是“设计一台较好的割草机”，在调查过许多种割

┊┊┊┊┊┊┊┊┊┊┊┊┊装┊┊┊┊┊订┊┊┊┊┊线┊┊┊┊┊┊┊┊┊┊┊┊┊草方法经仔细考虑之后，以为聪明的设计师回重述目标为“设计一种拔草剪短的工具”。这一新的目标陈述已经从有特色词“割草机”插入新的具体要求。对许多人来说，这个阶段也可能凭想象去考虑种种事情，如飞旋的刀片、有噪声的发动机等。通过反复深入研究便可以成功地避开这类想象，而且把问题的陈述概括的简练和清晰。作为一次练习，读者不妨列出十种剪短草的方法，更多的就不必要了，因为你已经要对十种较好的割草机进行设计。可以利用功能形象化避免对创造性的不必要的限制！

性能技术条件

当实际问题的背景已做详尽调查，设计目标已经陈述清楚，接着就应该准备建立一组性能技术条件。应该注意的是，性能技术条件不是设计技术条件，区别在于，性能技术条件定义系统必须做到什么，而设计技术条件是定义必须如何把它做出来。在这个设计阶段中，想要规定出如何完成目标是不明智的，意味着还属于表1-1中的构思阶段。性能技术条件目的是仔细定义与约束设计问题，使它既能求解而事实上又能把它解出来。有关“割草机”的一组性能技术条件见表1-2。

需要指出，约束设计问题的技术条件不应该过分地限制工程师的设计自由度。例如，对技术条件1规定要求用汽油发动机是不适宜的，因为还有其他可选用的动力装置，而且都能提供所要求的运动。同样，对技术条件2规定所有零件采用不锈钢也是愚蠢的，以为防锈亦可以采用其他联建的材料。简言之，性能技术条件即完整地定义了设计问题，又尽可能地规定出一般的一种式样，并且可以起到完成设计问题的契约定义的作用。最终的设计可以根据技术条件进行验收。

表 1-2 割草机的性能技术条件

1 机器自带动力供给系统

2 机器要求防锈

3 机器的成本要低于＄100004离机器50ft的声音强度小于80dB

5 机器每小时割草1/4acre

6 其他

构思与发明

这一步既充满挑战又有挫折。这一设计阶段也最能证明工程师的潜在能力，但也是最难的一步工作。不少研究都曾探索过“创造力”的现象，多数认为这是人类的一个共同特性。就所有的幼小儿童来说，亦显示出非常强的创造力。人类初生最初几年的创造力发展速度与程度当然要求有毛种天性。有些人认为，西方的教育方法由于鼓励统一性和限制个性而抑制儿童的自然创造力。从幼儿园小班的“线内着色”到大班的暗礁才没模仿写字都会抑制个性的发展，但却有力融合于社会。这对避免无政府状态或许是必须的，但有可能影响每个人的思想创造力。有一些人论点认为，创造力是可教会的，也有一些人指认为创造力是遗传的，无论哪一种说法都没有什么根据，其实一个人抑制或丧失的创造力是可以点燃的。另一些研究提出，几乎谁都可以利用人们的潜在创造力，而

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创新过程有许多技巧可以提高或激发设计问题的创新性求解。事实上，正如已经确定设计过程那样，也可以确定创新过程，见表1-3。这个过程可以看作是设计过程的一个子过程，也可以把它放在设计过程的各个阶段。这样，构思与发明步骤也可以放在这四个分步骤中。

表 1-3 创新过程

1 概念产生

2 挫折

3 酝酿

4 想出来了

概念产生这一步是最困难的，甚至连非常善于创新的人在按“需求”进行创新是也会遇到困难。目前，已经提出许多技巧可以改进一个概念的产生，其中最重要的是延期评判，意即指暂时停止评判，因为在此阶段无法评判所产生概念的质量，而应该把它放在更后的分析阶段谨慎地进行。这一步的目的是尽可能多地获得设计方案，甚至欢迎那种肤浅的、荒谬的想法，因为由此常可以引发出新的见识，并提出另一些更现实的方案。

集体自由讨论这是一种获得创新设计的成功的技巧。这种技巧要求成立一个由6～15人组成的小组，并尽力防止对创新的最大障碍的发生，如怕被嘲笑，即在一个组内的多数人因怕被别人笑话而不想提出对该项设计的真实想法。集体自由讨论的规则要求不许有人开玩笑和批评别人的提议，即使是荒谬的也无所谓。每一个参加者充当“抄写员”，并履行记录全部提议（哪怕表面看是非常可笑的）的职责。只有正当地去做，这种技巧是非常有趣的，并且由于互相启发有时可能造成想法“相互激发”，在短时间内便有大量的想法产生。但对质量的评判只能推迟到后期进行。

当单独工作时，必须采用其他技巧，常用的是类推与反演。类推时把手头问题与其他物理问题在某个领域内作模拟，如将一个机械问题转化为流体或电子问题。反演是把设计问题有力转向外，例如，考虑用什么方法可将运动的物体变为固定或者相反，这一点在后面可以看到。另一种有助于创新的有效计巧是同义词的应用，即先找出问题陈述中定义动作的动词，然后尽可能多地列出该动词的同义词。

例如：

问题陈述：将此物体从A点移动到B点。

行为动词是“移动”，其同义词有：推、拉、滑、挤、抛、射、喷射、跳跃。

不论采用何种技巧与方法，构思的目的是产生大量不具体涉及其性质的想法。在某些时候，要做到让你的“智力源泉”枯竭为止。在创新过程中，要使达到了这种程度，就称之为挫折。这时，可以在是把问题放下先去做其他事。当你的意识智力专致于其他有意思的事时，你的亚意识智力还在考虑这个设计问题，这一步就是所谓的酝酿。突然，在一个十分意外的时间和地点，一个想法出现在你的意识中，并且好像是显而易见和正确地解除了问题……想出来了！当这些解经后续的分析发现有一些缺陷时，如果是这样，

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在“激发人类创造性”的论文中，Wallen对创造性提出三点见解

·对问题的吸引力。

·集中注意事实，技术构思、资料和问题的背景材料。

·改组时期。

在这几个要求中首要的是解决问题的动力，其实前面说过的背景调查。改组时期是指挫折阶段（这时你的亚意识还在考虑这个问题）。Wallen 的论文指出，从创造者的证词可知，在这个改组时期，不考虑哪个具体问题，瞬时顿悟常常出现在放松或睡眠期间。因此，为了提高你的创造力，沉浸于问题及其背景材料里，然后放松，让你的亚意识努力工作。

分析

一旦进入设计过程的分析阶段，至少在暂时已有了一个选定的设计方案，并立刻可以采用最现代的分析方法，以考查该方案的技术特性。当经分析发现问题时，为确保设计成功，重复设计过程的前面既不是必要的。

选择

通过技术分析表明有几个可选用的设计方案时，一种最通用的办法是通过详细设计、样机和实验作出选择。选择过程也包括几个可选用设计方案的分析与结果的比较。当考虑多因素进行选择时，用分类方法中的决策矩阵可以选出最好的方案。图1-2为一种较好的剪草机的决策矩阵，每一个设计方案在矩阵中占一行，各列为待选设计方案的各项指标，如成本、使用简易性、效率、性能、可靠性和其他的适当指标。然后对每一项指标规定一个权因子，以量度它的相对重要程度。例如，对用户来说，可靠性要比成本是一个更为重要的判据，反之亦然。再用一个能反映每项指标好坏级别的数（如用1～10）填在矩阵表内。注意，这基本上是对设计指标的一种主观的定级。最后，需根据每一个设计的得分多少来考察设计方案，并做出决策。每项指标所定的计乘以权因子（权因子的选择通常是时期合为一个方便的数，如等于1）的总和即为该设计得的分。在使用这类结果时必须小心谨慎，因为原始资料、指标的定级以及权因子的选择都具有主观性!相信这些结果比进行论证更有诱惑力。决策矩阵的实际只把问题变成更容易处理的资料，且强迫设计者认真考虑每个设计各项指标的相对值，直至可以做出一个更合理的决策，以致于“最好”的设计。

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详细设计

这一步通常包括完成装配图和整套零件图的设计或计算机辅助设计（CAD）的各个零件的文件。在每张零件图上必须标注出全部尺寸、所用材料的性质。根据这些图样（或CAD文件）便可以设计出实验用的样机或实验模型。当在实验中发现一些缺陷时，需要进一步反复。

样机和实验

模型任何一项涉及直到把它制造出来和在实验之前基本上都不能保证设计的正确性或可行性。基于这个原因，通常要求制作样机的实物模型。数学模型虽然很有用，但由于需要简化和假设，总不能像物理模型那样完全正确地表征实际的系统。样机通常是非常昂贵的，但边缘尺寸制作一台装置来检验设计还是要经济得多。样机可以有多种形式，从按比例尺寸的模型到原尺寸的模型，都要经过简化，殃及只是原理的一种代表。比例模型是按照产品的复杂性将实际参数适当地缩小。例如，材料的体积长度尺寸立方变化，面积按平方变化，散发到周围环境的热量可以取与表面面积成比例。线性化缩放一个系统都可能导致与原尺寸系统性能上的差别。因此，按一定比例制作物理模型时必须谨慎。在设计连杆机构时，可以按所选择长度做的硬纸板用图钉联接起来做一个简单的模型，便可以从中获得大量的机构运动的特性和品质。作为一名设计师，应该习惯于制作这种简单连接的模型进行所设计的连杆机构的研究。

试验样机或模型的试验是把机器完全开动起来，并观察其功能，与广泛的测试设备连接可以精确地测量出位移、速度、加速度、力、温度及其他参数。犹滴实验也要求把温度和湿度控制在一定的范围内做。用微机还可以获得更多的、精确的、廉价的测量资料。

生产

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最后，还要用足够的时间、资金和精力为设计投入生产做好准备。生产是按最终设计方案的单间制造，也可以使新产品成千甚至上亿件的成批制造。当在制造中出现大量的次品时，说明设计好存在缺陷，这将使设计者难堪并造成浪费。由此进一步得到启发，对设计过程中的前面几个步骤应特别仔细，以保证设计产品的质量。

在工程领域内已广泛地采用上述设计过程。一般都把工程定义为工程师根据什么去做，但也有的定义为工程师做什么和如何做。既可以把工程看作是一种方法、一个途径、一个过程、一种解决问题的心态，也可以把它看作是一项活动。工程方法是一种完全的、精细的、全面考虑的方法。看起来，强调“精细”与鼓励开明的特质、无约束的创造性思维是互有矛盾，其实不然，两项活动不仅兼容而且可以共存。仅有一个创造性的原始思想如果没有或不能把它付诸实施，并简化到可实际应用的程度，那么他是没有用的。要避免这一点，每一位设计师都必须培养自己洞察问题实质的能力并不厌其烦地做好设计过程每个阶段必须做好的工作。例如，要把一项设计当作与自己声誉有关的事情去做，必须全面地定义设计问题，如果漏掉定义中的某些细节，则最终将导致去求解一个错误的问题。因此，设计师必须仔细地研究设计问题的有关背景材料，周密地考虑问题的正确概念解，然后必须对正确概念解做错详细地分析，最后还必须把所选用的街进行详细设计，直到确信最小的螺母与螺栓都能正常工作。要想把自己培养成为一名工程师或设计师，就必须约束自己做事要彻底，并从中养成一套符合逻辑的、有序的工作方法，甚至在酝酿重大的创造性构想和反复求解时也能如此。创新性和注意细节是工程设计获得成功所必须的两个品质。