三維數(shù)控工作臺(tái)的設(shè)計(jì)與開(kāi)發(fā)
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附錄一
Mechanical Engineering in the Information Age
In the early 1980s,engineers thought that massive research would be needed to speed up product development.As it turns out ,less research is actually needed because shortened product development cycles encourage engineers to use available technology.Developing a revolutionary technology for use in a new product is risky and prone to failure .Taking shot steps is a safer and usually more successful approach to product development.
Shorter product development cyclys are also beneficial in an engineering world in which both captical and labor are global.People who can design and manufacture various products can be found anywhere in the world,but containing a new idea is hard.Geographic distance is no longer a barrier to others finging out about your development six months into the process.If you are got a short development cycle,the situation is not catastrophic-as long as you maintain your lead,But if you are in the midist of a six-year development process and a competitor gets wind of your work,the project could be in more serious trouble.
In one respect, manufacturing could be said to be coming full circle. The first manufacturing was a cottage industry: the designer was also the manufacturing, conceiving and fabricating products one at a time. Eventually, the concept of the interchangeability of parts was developed, production was separated into separated into specialized functions, and identical parts were produced thousands at a time.Today, although the designer and manufacturing may not become one again, the functions are being drawn close in the movement toward an integrated manufacturing system.
It is perhaps ironic that, at a time when the market demands a high degree of product diversification, the necessity for increasing productivity and reducing cost is driving manufacturing toward integration into a coherent system, a continuous process in which parts do not spend as much as 95% of production time being moved around or waiting to be worked on.
The computer is the key to each of these twin requirements. It is the only tool that can provide the quick reflexes, the flexibility and speed, to meet a diversified market. And it is the only tool that enables the detailed analysis and the accessibility of accurate data necessary for the integration of the manufacturing system.
Today, nearly every market is a niche market, because customers are selective. If you ignore the potential for tailoring your product to specific customers’ needs, you will lose the major part of your market share —perhaps all of it. Since these niche markets are transient, your company needs to be in a position to respond to them quickly.
The emergence of niche markets and design on demand has altered the way engineers conduct research. Today, research is commonly directed toward solving particular problems. Although this situation is probably temporary, much uncommitted technology, developed at government expense or written off by major corporations, is available today at very low cost. Following modest modifications, such technology can often be used directly in product development, which allows many organizations to avoid the expense of an extensive research effort. Once the technology is free of major obstacles, the research effort can focus on overcoming the barriers to commercialization rather than on pursuing new and interesting, but undefined, alternatives.
When viewed in this perspective, engineering research must focus primarily on removing the barriers to rapid commercialization of known technologies. Much of this effort must address quality and reliability concerns, which are foremost in the minds of today’ consumers. Clearly, a reputation for poor quality is synonymous with bad business. Everything possible—including thorough inspection at the end of the manufacturing line and automatic replacement of defective products—must be done to assure that the customer receives a properly functioning product.
Research has to focus on the cost benefit of factors such as reliability. As reliability increase, manufacturing costs and the final cost of the system will decrease. Having 30 percent junk at the end of a production line not only costs a fortune but also creates an opportunity for a competitor to take your idea and sell it to your customers.
Central to the process of improving reliability and lowering costs is the intensive and widespread use of design software, witch allows engineers to speed up every stage of the design process. Shortening each stage, however, may not sufficiently reduce the time required for the entire process. Therefore, attention must also be devoted to concurrent engineering software with shared databases that can be accessed by all members of the design team.
As we move more fully into the information Age, success will require that the engineer process some unique knowledge of and experience in both the development and the management of technology. Success will require broad knowledge and skills as well as expertise in some key social and economic factors at work in the marketplace. Increasingly, in the future, routine problems will not justify heavy engineering expenditures, and engineers will be expected to work cooperatively in solving more challenging, more demanding problems in substantially less time. We have begun a new phase in the practice of engineering. It offers great promise and excitement as more and more problem-solving capability is placed in the hands of the computerized and unquenched thirst for better products and systems must be matched by the joy of creation that marks all great engineering endeavors. Mechanical engineering is a great profession, and it will become even greater as we make the most of the opportunities offered by the Information Age.
It may well be that, in the future, the computer may be essential to a company’s survival. Many of today’s businesses will fade away to be replaced by more productive combinations. Such more-productive combinations are super quality, super productivity plants. The goal is to design and operate a plant that would produce 100% satisfactory parts with good productivity.
A sophisticated, competitive world is requiring that manufacturing begin to settle for more, to become itself sophisticated. To meet competition, for example, a company will have to meet the somewhat conflicting demands for greater product diversification, higher quality, improved productivity, and low prices.
The company that seeks to meet these demands will need a sophisticated tool, one that will allow it to respond quickly to customer needs while getting the most out of its manufacturing resources.
The computer is that tool.
Becoming a “super quality, super productivity” plant requires the integration of an extremely complex system. This can be accomplished only when all elements of manufacturing-design, fabrication and assembly,quality assurance, management, materials handling—are computer integrated.
In product design, for example, interactive computer-aided-design (CAD) systems allow the drawing and analysis tasks to be performed in a fraction of the time previously required and with greater accuracy. And programs for prototype testing and evaluation further speed the design process.
In manufacturing planning, computer-aided process planning permits the selection, from thousands of possible sequences and schedules, of the optimum process.
On the shop floor, distributed intelligence in the form of microprocessors controlled machines, runs automated loading and unloading equipment, and collects data on current shop conditions.
But such isolated revolutions are not enough. What is needed is a totally automated system, linked by common software from front door to back.
The benefits range throughout the system. Essentially, computer integration provides widely and instantaneously available, accurate information, improving communication between departments, permitting tighter control, and generally enhancing the overall quality and efficiency of the entire system.
Improved communication can mean, for example, designs that are more producible. The NC programmer and the tool designer have a chance to influence the product designer, and vice versa.
Engineering changes, thus, can be reduced, and those that are required can be handled more efficiently. Not only dose the computer permit them to be specified more quickly, but it also alerts subsequent users of the data to the fact that a change has been made.
The instantaneous updating of production-control data permits better planning and more effective scheduling. Expensive equipment, therefore, is used more productively, and parts move more efficiently through production, reducing work-in-process costs.
Product quality, too, can be improved. Not only are more-accurate designs produced, for example, but the use of design data by the quality-assurance department helps eliminate errors due to misunderstandings.
People are enabled to do their jobs better. By eliminating tedious calculations and paperwork—not to mention time wasted searching for information—the computer not only allows workers to be more productive but also frees then to do what only human beings can do: think creatively.
Computer integration may also lure new people into manufacturing. People are attracted because they want to work in a modern, technologically sophisticated environment.
In manufacturing engineering, CAD/CAM decreases tool design, NC-programming, and planning times while speeding the response rate, which will eventually permit in-house staff to perform work that is currently being contracted out.
Computers have been used in nearly every manufacturing job. Computers improve the efficiency, accuracy, and productivity of many manufacturing processes. Just like the other tools and machines, computers extend human capabilities and make some jobs easier. Every department in manufacturing has found a use for computers.
In the management department, supervisors and managers use computers to gather information about the progress of work in all the other departments. In marketing, researchers, advertisers, and sales people use computers to get data on potential buyers, to study market research, and to create advertisements.
As we move more fully into the Information Age,success will require that the engineer possess some unique knowledge of and experience in both the development and the management of technology.Success will require broad knowledge and skills as well as expertise in some key technologies and disciplines;it will also require a keen awareness of the social and economica factors at work in the marketplace.Increasingly,in the future,routine problems will not justify heavy engineering expenditures,and engineers will be expected to work cooperatively in solving more challenging,more demanding problems in substantially less time.It offers great promise and excitement as more and more problem-solving capability is placed in the hands of the computerized and wired engineer.We have begun a new phase in the practice of engineering.Mechanical engineering is a great profession,ang it will become even greater as we make the most of the opportunities offered by the Information Age.
信息時(shí)代的機(jī)械工程
在80年代初工程師們?cè)?jīng)認(rèn)為要加快產(chǎn)品的研制開(kāi)發(fā),必須進(jìn)行大量的研究工作。結(jié)果是實(shí)際上只進(jìn)行了較少的見(jiàn)就工作,這是因?yàn)楫a(chǎn)品開(kāi)發(fā)周期的縮短,促使工程師們盡可能地利用現(xiàn)有的技術(shù)。研制開(kāi)發(fā)一種創(chuàng)新行得技術(shù)并將其應(yīng)用在新產(chǎn)品上,是有風(fēng)險(xiǎn)的,并且易于招致失敗。在產(chǎn)品開(kāi)發(fā)過(guò)程中采用較少的步驟是一種安全的和易于成功的方法。
對(duì)于資金和人力都處于全球性環(huán)境中的工程界而言,縮短產(chǎn)品研制開(kāi)發(fā)周期也是有益的。能夠設(shè)計(jì)和制造各種產(chǎn)品的人可以在世界各地找到。但是,具有創(chuàng)新思想的人則比較難找。對(duì)于你已經(jīng)進(jìn)行了6個(gè)月的研制開(kāi)發(fā)工作,地理上的距離已經(jīng)不再是其他人發(fā)現(xiàn)他的障礙。如果你的研制周期較短,只要你仍然保持領(lǐng)先,這種情況并不會(huì)造成嚴(yán)重后果。但如果你正處于一個(gè)長(zhǎng)達(dá)6年的研制開(kāi)發(fā)過(guò)程的中期,一個(gè)競(jìng)爭(zhēng)對(duì)手了解到你的研究工作的一些信息,這個(gè)項(xiàng)目將面臨比較大的麻煩。
從某一方面可以說(shuō),制造業(yè)正在完成一個(gè)循環(huán)。最初的制造業(yè)是家庭手工業(yè):設(shè)計(jì)者本身也是制造者,產(chǎn)品的構(gòu)思和加工由同一個(gè)人來(lái)完成。后來(lái),形成了零件的互換性這個(gè)概念,生產(chǎn)被依照專業(yè)功能分割開(kāi)來(lái),可以成批地生產(chǎn)數(shù)以千計(jì)的相同零件。
今天,盡管設(shè)計(jì)者與制造者不可能再是同一個(gè)人,但在向集成制造系統(tǒng)前進(jìn)的途中,這兩種功能已經(jīng)越來(lái)越靠近了。
可能具有諷刺意味的是,在市場(chǎng)需求高度多樣化產(chǎn)品的時(shí)候,提高生產(chǎn)率和降低成本的必要性促使制造業(yè)朝著集成為單調(diào)關(guān)聯(lián)系統(tǒng)方向變化。這是一個(gè)連續(xù)的過(guò)程,在其中零件不需要花費(fèi)多達(dá)95%的生產(chǎn)時(shí)間用在運(yùn)輸和等待加工上。
計(jì)算機(jī)是滿足這兩項(xiàng)要求中的任何一項(xiàng)的關(guān)鍵。它是能夠提供快速反應(yīng)能力、柔性和滿足多樣化市場(chǎng)的唯一工具。而且,它是實(shí)現(xiàn)制造系統(tǒng)集成所需要的、能夠進(jìn)行詳細(xì)分析和利用精確數(shù)據(jù)的唯一工具。
將來(lái),計(jì)算機(jī)可能是一個(gè)企業(yè)生存的基本條件,許多現(xiàn)今的獎(jiǎng)杯生產(chǎn)能力更高的企業(yè)組合所取代。這些生產(chǎn)能力更高的企業(yè)組合是一些具有非常高的質(zhì)量、非常高的生產(chǎn)率的工廠。目標(biāo)是的設(shè)計(jì)和運(yùn)行一個(gè)能以高生產(chǎn)率的方式生產(chǎn)100%合格產(chǎn)品的工廠。
一個(gè)采用先進(jìn)技術(shù)的、競(jìng)爭(zhēng)的世界正在促進(jìn)制造業(yè)開(kāi)始做更多的工作,使其本身采用先進(jìn)的技術(shù)。為了適應(yīng)競(jìng)爭(zhēng),一個(gè)公司會(huì)滿足一些在某種程度上相互矛盾的要求,諸如產(chǎn)品多樣化、提高質(zhì)量、增加生產(chǎn)率、降低價(jià)格。在努力滿足這些要求的過(guò)程中,公司需要一個(gè)采用先進(jìn)技術(shù)的工具,一個(gè)能夠?qū)︻櫩偷男枨笞龀隹焖俜磻?yīng),而且從制造資源中獲得最大收益的工具。
計(jì)算機(jī)就是這個(gè)工具。
成為一個(gè)具有“非常高的質(zhì)量、非常高的生產(chǎn)率”的工廠,需要對(duì)一個(gè)非常復(fù)雜的系統(tǒng)進(jìn)行集成。這只是通過(guò)采用計(jì)算機(jī)對(duì)機(jī)械制造的所有組成部分—設(shè)計(jì)、加工、裝配、質(zhì)量保證、管理和材料裝卸及輸送進(jìn)行集成才能完成。
例如,在產(chǎn)品設(shè)計(jì)期間,交互式的計(jì)算機(jī)輔助設(shè)計(jì)系統(tǒng)使得完成繪圖和和分析工作所需要的時(shí)間比原來(lái)減少,而且精確程度得到了很大的提高。此外,樣機(jī)的實(shí)驗(yàn)與評(píng)價(jià)程序進(jìn)一步加快了設(shè)計(jì)進(jìn)程。
在制定制造計(jì)劃時(shí),計(jì)算機(jī)輔助編制工藝規(guī)程可以從數(shù)以千計(jì)的工序和加工過(guò)程中選擇最好的加工方案。
在車(chē)間里,分布式智能以微機(jī)處理器這種方式來(lái)控制機(jī)床、從總自動(dòng)裝卸設(shè)備和收集關(guān)于當(dāng)前車(chē)間狀態(tài)的信息。
但是這些各自獨(dú)立的改革還遠(yuǎn)遠(yuǎn)不夠。我沒(méi)所需要的是由一個(gè)通用軟件從始端到終端進(jìn)行控制的全部自動(dòng)化的系統(tǒng)。
整個(gè)系統(tǒng)都會(huì)從中受益。基本上,計(jì)算機(jī)集成可以提供廣泛的、及時(shí)地和精確度的信息,可以改進(jìn)各部門(mén)之間的交流與溝通,實(shí)施更嚴(yán)格的控制,而且通常能夠增強(qiáng)整個(gè)系統(tǒng)的全面質(zhì)量和效率。
例如,改進(jìn)交流和溝通意味著會(huì)使設(shè)計(jì)具有更好的可制造性。數(shù)控編程人員和工藝裝配設(shè)計(jì)人員有機(jī)會(huì)向產(chǎn)品設(shè)計(jì)人員提出意見(jiàn),反之亦然。
因而可以減少技術(shù)方面的變更,而對(duì)于那些必要的變更,可以更有效地進(jìn)行處理。計(jì)算機(jī)不僅能夠更快地對(duì)變更之處做出詳細(xì)的說(shuō)明,而且還能夠把變更之后的數(shù)據(jù)告訴隨后的使用者。
利用及時(shí)更新的生產(chǎn)控制數(shù)據(jù)可以制定更好的工藝規(guī)程和更有效率的生產(chǎn)進(jìn)度。因而,可使昂貴的設(shè)備得到更好的利用,提高零件在生產(chǎn)過(guò)程中的運(yùn)送效率,減少在制品的成本。
產(chǎn)品質(zhì)量也可得到改進(jìn)。例如,不僅可以提高設(shè)計(jì)精度,還可以是質(zhì)量保證部門(mén)利用設(shè)計(jì)數(shù)據(jù),避免由于誤解而產(chǎn)生錯(cuò)誤。
可使人們更好的完成他們的工作。通過(guò)避免冗長(zhǎng)的計(jì)算和書(shū)寫(xiě)工作—這還不算查找資料所浪費(fèi)的時(shí)間—計(jì)算機(jī)不僅使人們更有效的工作,而且還能把他們解放出來(lái)去做只有人類才能做的工作:創(chuàng)造性的思考
計(jì)算機(jī)集成制造還會(huì)吸引新的人才進(jìn)入制造業(yè)。人才被吸引過(guò)來(lái)的原因是他們希望到一個(gè)現(xiàn)代化的、技術(shù)先進(jìn)的環(huán)境中工作。
在制造工程中,CAD/CAM減少了工藝裝備設(shè)計(jì)、數(shù)控編程和編制工藝規(guī)程所需要的時(shí)間。同時(shí)加快了響應(yīng)速度,這最終將會(huì)使目前外圍加工的工作由公司內(nèi)部人員來(lái)完成。
今天,因?yàn)轭櫩蛡冇休^大的選擇余地,幾乎所有市場(chǎng)都是特殊定向產(chǎn)品市場(chǎng)。如果你不能使你的產(chǎn)品滿足某些特定客戶的要求,你將失掉你的市場(chǎng)份額中的一大部分,或者失掉全部份額。由于這些定向產(chǎn)品市場(chǎng)是經(jīng)常變化的,你的公司應(yīng)該對(duì)市場(chǎng)的變化做出快速的反應(yīng)。
定向產(chǎn)品市場(chǎng)和根據(jù)客戶要求進(jìn)行設(shè)計(jì)這種現(xiàn)象的出現(xiàn)改變了工程師的研究工作的方式。今天,研究工作通常是針對(duì)解決特定問(wèn)題進(jìn)行的 ?,F(xiàn)在許多由政府資助或者由大公司出資開(kāi)發(fā)的技術(shù)可以在非常低的成本下被自由使用,盡管這種情況可能是暫時(shí)的。在對(duì)這些技術(shù)進(jìn)行適當(dāng)改進(jìn)后,他們通常能夠被直接用于產(chǎn)品開(kāi)發(fā),這使得許多公司可以節(jié)省昂貴的研究經(jīng)費(fèi)。在主要的技術(shù)障礙被克服后,研究工作應(yīng)該主要致力于產(chǎn)品的商品化方面,而不是開(kāi)發(fā)新的、有趣的、不確定的替代產(chǎn)品。
采用上述觀點(diǎn)看問(wèn)題,工程研究應(yīng)該致力于消除將已知技術(shù)快速商品化的障礙。工作的重點(diǎn)是產(chǎn)品的可靠性,這些在當(dāng)今顧客的頭腦中是最重要的。很明顯,一個(gè)質(zhì)量差的聲譽(yù)是一個(gè)不好企業(yè)的代名詞。企業(yè)應(yīng)該盡最大努力來(lái)保證顧客得到合格的產(chǎn)品,這個(gè)努力包括在生產(chǎn)線的終端對(duì)產(chǎn)品進(jìn)行嚴(yán)格的檢驗(yàn)和自動(dòng)更換有缺陷的產(chǎn)品。
研究工作應(yīng)該著重考慮諸如可靠性等因素對(duì)成本帶來(lái)的益處。當(dāng)可靠性提高時(shí),制造成本和系統(tǒng)的最終成本將會(huì)降低。如果在生產(chǎn)線的終端產(chǎn)生了30%的廢品,這不僅會(huì)浪費(fèi)金錢(qián),也會(huì)給你的競(jìng)爭(zhēng)對(duì)手創(chuàng)造一個(gè)利用你的想法制造產(chǎn)品,并將其銷(xiāo)售給你的客戶的良機(jī)。
提高可靠性和降低成本這個(gè)過(guò)程的關(guān)鍵是深入、廣泛地利用設(shè)計(jì)軟件。設(shè)計(jì)軟件可以使工程師們加快每一階段的設(shè)計(jì)工作。然而,僅僅縮短每一階段的設(shè)計(jì)時(shí)間,可能不會(huì)顯著地縮短整個(gè)設(shè)計(jì)過(guò)程的時(shí)間。因而,必須致力于采用并行工程軟件,這樣可以使所有設(shè)計(jì)組的成員都能使用共今天,因?yàn)轭櫩蛡冇休^大的選擇余地,幾乎所有市場(chǎng)都是特殊定向產(chǎn)品市場(chǎng)。如果你不能使你的產(chǎn)品滿足某些特定客戶的要求,你將失掉你的市場(chǎng)份額中的一大部分,或者失掉全部份額。由于這些定向產(chǎn)品市場(chǎng)是經(jīng)常變化的,你的公司應(yīng)該對(duì)市場(chǎng)的變化做出快速的反應(yīng)。
根據(jù)《工具與制造工程師手冊(cè)》,工藝設(shè)計(jì)就是系統(tǒng)地確定能夠經(jīng)濟(jì)的和有競(jìng)爭(zhēng)力的將產(chǎn)品制造出來(lái)的方法。它主要由選擇、計(jì)算和建立工藝文件組成。對(duì)加工方法、機(jī)床、刀具、工序和順序必須進(jìn)行選擇。對(duì)于一些參數(shù)如進(jìn)給量、速度、公差、尺寸和成本等應(yīng)該進(jìn)行計(jì)算。最后,應(yīng)該建立加工說(shuō)明、帶工序簡(jiǎn)圖的工藝過(guò)程卡和加工路線等方面的工藝文件。工藝設(shè)計(jì)是產(chǎn)品設(shè)計(jì)和制造的中間環(huán)節(jié)。那么,它是如何將設(shè)計(jì)與制造連接起來(lái)的呢?
大部分制造工程師都會(huì)同意這個(gè)看法,即如果10個(gè)不同的工藝人員進(jìn)行同一個(gè)零件的工藝設(shè)計(jì),他們很可能得出10種不同的方案。顯然,所有這些方案都不能反映最適當(dāng)?shù)闹圃旆椒?,而且,事?shí)上也不能保證它們中的任何一個(gè)方案是由加工這個(gè)零件的最好的方法組成的。
隨著我們步入信息時(shí)代,要取得成功,工程師們?cè)诩夹g(shù)開(kāi)發(fā)和技術(shù)管理方面都應(yīng)該具有一些獨(dú)特的知識(shí)和經(jīng)驗(yàn)。成功的工程師們不但應(yīng)該具有寬廣的知識(shí)和技能,而且還應(yīng)該是某些關(guān)鍵技術(shù)或?qū)W科的專家,他們還應(yīng)該在社會(huì)因素和經(jīng)濟(jì)因素對(duì)市場(chǎng)影響方面有敏銳洞察能力。將來(lái),花在解決日常工程問(wèn)題上的費(fèi)用將會(huì)減少,工程師們將會(huì)在一些更富有挑戰(zhàn)行,更急需解決的問(wèn)題上協(xié)同工作,大大縮短解決這些問(wèn)題所需要的時(shí)間。計(jì)算機(jī)和網(wǎng)絡(luò)使工程師們具有了越來(lái)越多的解決問(wèn)題的能力,這也給他們的工作帶來(lái)很大的希望和喜悅。我們已經(jīng)開(kāi)始了工程實(shí)踐的新階段。機(jī)械工程是一個(gè)偉大的行業(yè),當(dāng)我們充分利用了信息時(shí)代所提供的及預(yù)后,他將變得更加偉大。
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