銑床半軸夾具設(shè)計【銑φ38端面】【說明書+CAD】,銑φ38端面,說明書+CAD,銑床半軸夾具設(shè)計【銑φ38端面】【說明書+CAD】,銑床,夾具,設(shè)計,38,端面,說明書,CAD 附件1：外文資料翻譯譯文 機械設(shè)計 摘要： 機器是由機械裝置和其它組件組成的。它是一種用來轉(zhuǎn)換或傳遞能量的裝置，例如：發(fā)動機、渦輪機、車輛、起重機、印刷機、洗衣機、照相機和攝影機等。許多原則和設(shè)計方法不但適用于機器的設(shè)計，也適用于非機器的設(shè)計。術(shù)語中的“機械裝置設(shè)計” 的含義要比“機械設(shè)計”的含義更為廣泛一些，機械裝置設(shè)計包括機械設(shè)計。在分析運動及設(shè)計結(jié)構(gòu)時，要把產(chǎn)品外型以及以后的保養(yǎng)也要考慮在機械設(shè)計中。在機械工程領(lǐng)域中，以及其它工程領(lǐng)域中，所有這些都需要機械設(shè)備，比如：開關(guān)、凸輪、閥門、船舶以及攪拌機等。 關(guān)鍵詞： 設(shè)計流程 設(shè)計規(guī)則 機械設(shè)計 設(shè)計流程 設(shè)計開始之前就要想到機器的實際性，現(xiàn)存的機器需要在耐用性、效率、重量、速度，或者成本上得到改善。新的機器必需具有以前機器所能執(zhí)行的功能。 在設(shè)計的初始階段，應(yīng)該允許設(shè)計人員充分發(fā)揮創(chuàng)造性，不要受到任何約束。即使產(chǎn)生了許多不切實際的想法，也會在設(shè)計的早期，即在繪制圖紙之前被改正掉。只有這樣，才不致于阻斷創(chuàng)新的思路。通常,還要提出幾套設(shè)計方案，然后加以比較。很有可能在這個計劃最后決定中,使用了某些不在計劃之內(nèi)的一些設(shè)想。 一般的當(dāng)外型特點和組件部分的尺寸特點分析得透徹時，就可以全面的設(shè)計和分析。接著還要客觀的分析機器性能的優(yōu)越性，以及它的安全、重量、耐用性，并且競爭力的成本也要考慮在分析結(jié)果之內(nèi)。每一個至關(guān)重要的部分要優(yōu)化它的比例和尺寸，同時也要保持與其它組成部分相協(xié)調(diào)。 也要選擇原材料和處理原材料的方法。通過力學(xué)原理來分析和實現(xiàn)這些重要的特性，如那些靜態(tài)反應(yīng)的能量和摩擦力的最佳利用，像動力慣性、加速動力和能量；包括彈性材料的強度、應(yīng)力和剛度等材料的物理特性，以及流體潤滑和驅(qū)動器的流體力學(xué)。設(shè)計的過程是重復(fù)和合作的過程，無論是正式或非正式的進(jìn)行，對設(shè)計者來說每個階段都很重要。 最后，以圖樣為設(shè)計的標(biāo)準(zhǔn)，并建立將來的模型。如果它的測試是符合事先要求的，則再將對初步設(shè)計進(jìn)行某些修改，使它能夠在制造成本上有所降低。產(chǎn)品的設(shè)計需要不斷探索和發(fā)展。許多方案必須被研究、試驗、完善，然后決定使用還是放棄。雖然每個工程學(xué)問題的內(nèi)容是獨特的，但是設(shè)計師可以按照類似的步驟來解決問題。 產(chǎn)品的責(zé)任訴訟迫使設(shè)計人員和公司在選擇材料時，采用最好的程序。在材料過程中，五個最常見的問題為：（a）不了解或者不會使用關(guān)于材料應(yīng)用方面的最新最好的信息資料；(b)未能預(yù)見和考慮材料的合理用途（如有可能，設(shè)計人員還應(yīng)進(jìn)一步預(yù)測和考慮由于產(chǎn)品使用方法不當(dāng)造成的后果。在近年來的許多產(chǎn)品責(zé)任訴訟案件中，由于錯誤地使用產(chǎn)品而受到傷害的原告控告生產(chǎn)廠家，并且贏得判決）；(c)所使用的材料的數(shù)據(jù)不全或是有些數(shù)據(jù)不確定，尤其是當(dāng)其性能數(shù)據(jù)長期不更新；(d)質(zhì)量控制方法不適當(dāng)和未經(jīng)驗證；(e)由一些完全不稱職的人員選擇材料。 通過對上述五個問題的分析，可以得出這些問題是沒有充分理由而存在的結(jié)論。對這些問題的研究分析可以為避免這些問題的出現(xiàn)而指明方向。盡管采用最好的材料選擇方法也不能避免發(fā)生產(chǎn)品責(zé)任訴訟，設(shè)計人員和工業(yè)界按照適當(dāng)?shù)某绦蜻M(jìn)行材料選擇，可以大大減少訴訟的數(shù)量。 從以上的討論可以看出，選擇材料的人們應(yīng)該對材料的性質(zhì)，特點和加工方法有一個全面而基本的了解。 在隨后生產(chǎn)和售后服務(wù)的幾年中，要接受新觀念的變化，或者由試驗和經(jīng)驗為基礎(chǔ)，進(jìn)一步分析并改進(jìn)。 一些設(shè)計規(guī)則 在本節(jié)中，建議要運用創(chuàng)造性的態(tài)度來替代和改進(jìn)。也許會創(chuàng)造出更實用、更經(jīng)濟(jì)、更耐用的產(chǎn)品。 為了激發(fā)創(chuàng)造性思維，下列是設(shè)計和分析的建議規(guī)則。前六個規(guī)則對設(shè)計者來說特別適用。 1. 要有創(chuàng)造性的利用所需要的物理性質(zhì)和控制過程。 2. 認(rèn)識負(fù)載產(chǎn)生的影響及其意義。 3. 預(yù)測沒有想到的負(fù)載。 4. 創(chuàng)造出對載荷更為有利的條件。 5. 提供良好的應(yīng)力分布和最小的剛度條件。 6. 運用最簡單的方程來優(yōu)化體積和面積。 7. 選擇組合材料。 8. 仔細(xì)選擇所備的原料和不可缺少的組件。 9. 調(diào)整有效的設(shè)計方案，以適應(yīng)生產(chǎn)過程和降低成本。 10. 規(guī)定好準(zhǔn)確的位置條件為了使組件安裝時不干涉。 機械設(shè)計包括一下內(nèi)容： 1. 對設(shè)計過程、設(shè)計所需要公式以及安全系數(shù)進(jìn)行介紹。 2. 回顧材料特性、靜態(tài)和動態(tài)載荷分析，包括梁、振動和沖擊載荷。 3. 回顧應(yīng)力的基本規(guī)律和失效分析。 4. 介紹靜態(tài)失效理論和靜態(tài)載荷下機械斷裂分析。 5. 介紹疲勞失效理論并強調(diào)在壓力條件下接近高循環(huán)的疲勞設(shè)計，這通常用在旋轉(zhuǎn)機械的設(shè)計中。 6. 深入探討機械磨損機理、表面接觸應(yīng)力和表面疲勞現(xiàn)象。 7. 使用疲勞分析技術(shù)校核軸的設(shè)計。 8. 討論潤滑油膜與滾動軸承的理論和應(yīng)用。 9. 深入介紹直齒圓柱齒輪的動力學(xué)、設(shè)計和應(yīng)力分析，并簡單介紹斜齒輪、錐齒輪和渦輪有關(guān)方面的問題。 10. 討論彈簧設(shè)計、螺桿等緊固件的設(shè)計，包括傳動螺桿和預(yù)緊固件。 11. 介紹盤式和鼓式離合器以及制動器的設(shè)計和技術(shù)說明。 機械設(shè)計 一臺完整機器的設(shè)計是一個復(fù)雜的過程。機械設(shè)計是一項創(chuàng)造性的工作。設(shè)計工程師不僅在工作上要有創(chuàng)造性，還必須在機械制圖、運動學(xué)、工程材料、材料力學(xué)和機械制造工藝學(xué)等方面具有深厚的基礎(chǔ)知識。 任何產(chǎn)品在設(shè)計時第一步就是選擇產(chǎn)品每個部分的構(gòu)成材料。許多的材料被今天的設(shè)計師所使用。對產(chǎn)品的功能，它的外觀、材料的成本、制造的成本作出必要的選擇是十分重要的。對材料的特性必須事先作出仔細(xì)的評估。 仔細(xì)精確的計算是必要的，以確保設(shè)計的有效性。在任何失敗的情況下，最好知道在最初設(shè)計中有有缺陷的部件。計算（圖紙尺寸）檢查是非常重要的。一個小數(shù)點的位置放錯，就可以導(dǎo)致一個本可以完成的項目失敗。設(shè)計工作的各個方面都應(yīng)該檢查和復(fù)查。 計算機是一種工具，它能夠幫助機械設(shè)計師減輕繁瑣的計算，并對現(xiàn)有數(shù)據(jù)提供進(jìn)一步的分析。互動系統(tǒng)基于計算機的能力，已經(jīng)使計算機輔助設(shè)計（CAD）和計算機輔助制造（CAM）成為了可能。心理學(xué)家經(jīng)常談?wù)撊绾问谷藗冞m應(yīng)他們所操作的機器。設(shè)計人員的基本職責(zé)是努力使機器來適應(yīng)人們。這并不是一項容易的工作，因為實際上并不存在著一個對所有人來說都是最優(yōu)的操作范圍和操作過程。另一個重要問題，設(shè)計工程師必須能夠同其他有關(guān)人員進(jìn)行交流和磋商。在開始階段，設(shè)計人員必須就初步設(shè)計同管理人員進(jìn)行交流和磋商，并得到批準(zhǔn)。這一般是通過口頭討論，草圖和文字材料進(jìn)行的。 如前所訴，機械設(shè)計的目的是生產(chǎn)能夠滿足人類需求的產(chǎn)品。發(fā)明、發(fā)現(xiàn)和科技知識本身并不一定能給人類帶來好處，只有當(dāng)它們被應(yīng)用在產(chǎn)品上才能產(chǎn)生效益。因而，應(yīng)該認(rèn)識到在一個特定的產(chǎn)品進(jìn)行設(shè)計之前，必須先確定人們是否需要這種產(chǎn)品。 應(yīng)當(dāng)把機械設(shè)計看成是機械設(shè)計人員運用創(chuàng)造性的才能進(jìn)行產(chǎn)品設(shè)計、系統(tǒng)分析和制定產(chǎn)品的制造工藝學(xué)的一個良機。掌握工程基礎(chǔ)知識要比熟記一些數(shù)據(jù)和公式更為重要。僅僅使用數(shù)據(jù)和公式是不足以在一個好的設(shè)計中做出所需的全部決定的。另一方面，應(yīng)該認(rèn)真精確的進(jìn)行所有運算。例如，即使將一個小數(shù)點的位置放錯，也會使正確的設(shè)計變成錯誤的。 一個好的設(shè)計人員應(yīng)該勇于提出新的想法，而且愿意承擔(dān)一定的風(fēng)險，當(dāng)新的方法不適用時，就使用原來的方法。因此，設(shè)計人員必須要有耐心，因為 所花費的時間和努力并不能保證帶來成功。一個全新的設(shè)計，要求屏棄許多陳舊的，為人們所熟知的方法。由于許多人墨守成規(guī)，這樣做并不是一件容易的事。一位機械設(shè)計師應(yīng)該不斷地探索改進(jìn)現(xiàn)有的產(chǎn)品的方法，在此過程中應(yīng)該認(rèn)真選擇原有的、經(jīng)過驗證的設(shè)計原理，將其與未經(jīng)過驗證的新觀念結(jié)合起來。 新設(shè)計本身會有許多缺陷和未能預(yù)料的問題發(fā)生，只有當(dāng)這些缺陷和問題被解決之后，才能體現(xiàn)出新產(chǎn)品的優(yōu)越性。因此，一個性能優(yōu)越的產(chǎn)品誕生的同時，也伴隨著較高的風(fēng)險。應(yīng)該強調(diào)的是，如果設(shè)計本身不要求采用全新的方法，就沒有必要僅僅為了變革的目的而采用新方法。 附件2：外文原文（復(fù)印件） Mechanical Design Abstract: A machine is a combination of mechanisms and other components which transforms, transmits. Examples are engines, turbines, vehicles, hoists, printing presses, washing machines, and movie cameras. Many of the principles and methods of design that apply to machines also apply to manufactured articles that are not true machines. The term "mechanical design" is used in a broader sense than "machine design" to include their design. the motion and structural aspects and the provisions for retention and enclosure are considerations in mechanical design. Applications occur in the field of mechanical engineering, and in other engineering fields as well, all of which require mechanical devices, such as switches, cams, valves, vessels, and mixers. Keywords: Mechanical Design mechanisms Design Process The Design Process Designing starts with a need real.Existing apparatus may need improvements in durability, efficiency, weight, speed, or cost. New apparatus may be needed to perform a function previously done by men, such as computation, assembly, or servicing. With the objective wholly or partly In the design preliminary stage, should allow to design the personnel fully to display the creativity, not each kind of restraint. Even if has had many impractical ideas, also can in the design early time, namely in front of the plan blueprint is corrected. Only then, only then does not send to stops up the innovation the mentality. Usually, must propose several sets of design proposals, then perform the comparison. Has the possibility very much in the plan which finally designated, has used certain not in plan some ideas which accepts. When the general shape and a few dimensions of the several components become apparent, analysis can begin in earnest. The analysis will have as its objective satisfactory or superior performance, plus safety and durability with minimum weight, and a competitive cost. Optimum proportions and dimensions will be sought for each critically loaded section, together with a balance between the strengths of the several 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 static 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 and deflection; of physical behavior of materials; and of fluid mechanics for lubrication and hydrodynamic drives. The analyses may be made by the same engineer who conceived the arrangement of mechanisms, or, in a large company, they may be made by a separate analysis division or research group. Design is a reiterative and cooperative process, whether done formally or informally, and the analyst can contribute to phases other than his own. Product design requires much research and development. Many Concepts of an idea must be studied, tried, and then either used or discarded. Although the content of each engineering problem is unique, the designers follow the similar process to solve the problems. Product liability suits designers and forced in material selection, using the best program. In the process of material, the most common problems for five (a) don't understand or not use about the latest application materials to the best information, (b) failed to foresee and consider the reasonable use material may (such as possible, designers should further forecast and consider due to improper use products. In recent years, many products liability in litigation, the use of products and hurt the plaintiff accused manufacturer, and won the decision), (c) of the materials used all or some of the data, data, especially when the uncertainty long-term performance data is so, (d) quality control method is not suitable and unproven, (e) by some completely incompetent persons choose materials. Through to the above five questions analysis, may obtain these questions is does not have the sufficient reason existence the conclusion. May for avoid these questions to these questions research analyses the appearance indicating the direction. Although uses the best choice of material method not to be able to avoid having the product responsibility lawsuit, designs the personnel and the industry carries on the choice of material according to the suitable procedure, may greatly reduce the lawsuit the quantity. May see from the above discussion, the choice material people should to the material nature, the characteristic and the processing method have comprehensive and the basic understanding. Finally, a design based upon function, and a prototype may be built. If its tests are satisfactory, the initial design will undergo certain modifications that enable it to be manufactured in quantity at a lower cost. During subsequent years of manufacture and service, the design is likely to undergo changes as new ideas are conceived or as further analyses based upon tests and experience indicate alterations. Sales appeal. Some Rules for Design In this section it is suggested that, applied with a creative attitude, analyses can lead to important improvements and to the conception and perfection of alternate, perhaps more functional, economical, and durable products. To stimulate creative thought, the following rules are suggested for the designer and analyst. The first six rules are particularly applicable for the analyst. 1. A creative use of need of physical properties and control process. 2. Recognize functional loads and their significance. 3. Anticipate unintentional loads. 4. Devise more favorable loading conditions. 5. Provide for favorable stress distribution and stiffness with minimum weight. 6. Use basic equations to proportion and optimize dimensions. 7. Choose materials for a combination of properties. 8. Select carefully, stock and integral components. 9. Modify a functional design to fit the manufacturing process and reduce cost. 10. Provide for accurate location and noninterference of parts in assembly. Machinery design covers the following contents. 1. Provides an introduction to the design process , problem formulation ,safety factors. 2. Reviews the material properties and static and dynamic loading analysis , Including beam , vibration and impact loading. 3. Reviews the fundamentals of stress and defection analysis. 4. Introduces fatigue-failure theory with the emphasis on stress-life approaches to high-cycle fatigue design, which is commonly used in the design of rotation machinery. 5. Discusses thoroughly the phenomena of wear mechanisms, surface contact stresses ,and surface fatigue. 6. Investigates shaft design using the fatigue-analysis techniques. 7. Discusses fluid-film and rolling-element bearing theory and application 8. Gives a thorough introduction to the kinematics, design and stress analysis of spur gears , and a simple introduction to helical ,bevel ,and worm gearing. 9. Discusses spring design including compression ,extension and torsion springs. 10. Deals with screws and fasteners including power screw and preload fasteners. 11. Introduces the design and specification of disk and drum clutches and brakes. Machine Design The complete design of a machine is a complex process. The machine design is a creative work. Project engineer not only must have the creativity in the work, but also must in aspect and so on mechanical drawing, kinematics, engineerig material, materials mechanics and machine manufacture technology has the deep elementary knowledge. One of the first steps in the design of any product is to select the material from which each part is to be made. Numerous materials are available to today's designers. The function of the product, its appearance, the cost of the material, and the cost of fabrication are important in making a selection. A careful evaluation of the properties of a. material must be made prior to any calculations. Careful calculations are necessary to ensure the validity of a design. In case of any part failures, it is desirable to know what was done in originally designing the defective components. The checking of calculations (and drawing dimensions) is of utmost importance. The misplacement of one decimal point can ruin an otherwise acceptable project. All aspects of design work should be checked and rechecked. The computer is a tool helpful to mechanical designers to lighten tedious calculations, and provide extended analysis of available data. Interactive systems, based on computer capabilities, have made possible the concepts of computer aided design (CAD) and computer-aided manufacturing (CAM). How does the psychologist frequently discuss causes the machine which the people adapts them to operate. Designs personnel''s basic responsibility is diligently causes the machine to adapt the people. This certainly is not an easy work, because certainly does not have to all people to say in fact all is the most superior operating area and the operating process. Another important question, project engineer must be able to carry on the exchange and the consultation with other concerned personnel. In the initial stage, designs the personnel to have to carry on the exchange and the consultation on the preliminary design with the administrative personnel, and is approved. This generally is through the oral discussion, the schematic diagram and the writing material carries on. If front sues, the machine design goal is the production can meet the human need the product. The invention, the discovery and technical knowledge itself certainly not necessarily can bring the advantage to the humanity, only has when they are applied can produce on the product the benefit. Thus, should realize to carries on before the design in a specific product, must first determine whether the people do need this kind of product Must regard as the machine design is the machine design personnel carries on using creative ability the product design, the system analysis and a formulation product manufacture technology good opportunity. Grasps the project elementary knowledge to have to memorize some data and the formula is more important than. The merely service data and the formula is insufficient to the completely decision which makes in a good design needs. On the other hand, should be earnest precisely carries on all operations. For example, even if places wrong a decimal point position, also can cause the correct design to turn wrongly. A good design personnel should dare to propose the new idea, moreover is willing to undertake the certain risk, when the new method is not suitable, use original method. Therefore, designs the personnel to have to have to have the patience, because spends the time and the endeavor certainly cannot guarantee brings successfully. A brand-new design, the request screen abandons obsoletely many, knows very well the method for the people. Because many person of conservativeness, does this certainly is not an easy matter. A mechanical designer should unceasingly explore the improvement existing product the method, should earnestly choose originally, the process confirmation principle of design in this process, with has not unified it after the confirmation new idea. Journal of Materials Processing Technology Journal of Materials Processing Technology 128（2002）7-18：1510—1515 Elsevier Science B.V. Knowledge model as an integral way to reuse the knowledge for fixture design process Charles W. Beardsley Abstract: The fixture design is considered a complex process that demands the knowledge of different areas, such as geometry, tolerances, dimensions, processes and manufacturing resources. Nowadays, the fixture design process is o-riented to automated systems based on knowledge models. These models describe the characteristics and relationships of the physical elements together withthe inference processes that allow carrying out the activity of fixture design. With the employment of the knowledge models, besides the automation, it ispossible to systematize and structure the knowledge of the fixture design process. With the use of specific methodologies, as the knowledge template, it ispossible to reuse the knowledge represented in a model, for its use in a different design process. The knowledge template represents a pattern that defines the common entities and inference processes to use in the design process .In this work, with the use of knowledge template we propose the reuse of the knowledge described in the design process of fixtures for machining to other types of fixtures uses like inspection, assembly or welding. ? 2005 Elsevier B.V. All rights reserved.. Keywords: Knowledge model; Knowledge template; Fixture design Page 9 1. Introduction The continuous challenge that involves the knowledge representation hasoriented to many different research groups to develop methodologies that describe stages for capture and representation of the knowledge in design and manufacturing systems [1–3]. This has allowed to define knowledge models as a tool that helps us to clarify the structure of intensive knowledge and information-processing tasks. In this sense, a knowledge model provides a specification of the data and inference processes required by the system of study [4]. A first approach in the development of knowledge models applied to machining fixtures design process has been proposed by Hunter [5]. During the last decade, the use of modelling techniques has allowed usto represent the fixture design process employed in some manufacturing operations, such as machining, assembly and inspection, etc. [6]. Due to the complexity and the wide scope of the fixture design process, different research groups have been focused in the analysis of specific activities of this process,such as fixture configuration, tolerance analyses, stability and accessibility. A great number of investigations has taken in consideration the way inwhich represent the knowledge used in the fixture design process. These researches are focused in the documentation of the design parameters, the structuring of the information of the fixture and the description of the fixture elements used in fixture design [2,7]. On the other hand, the implementation of the knowledge used in the fixture design can be classified regarding the artificial intelligence technique(AI) used [8,9] and on the automation level of t-he design system[2]. However, whatever it is the artificial intelligence technique used and the automation level of this type of systems, the process of knowledge modelling in the fixture design is important for several reasons: the need to specify the concepts used in the fixture design; to establish the relationships amongdifferent knowledge groups; to develop knowledge based systems (KBS), and finally, to provide a conceptual base for reusing the knowledge. In this sense, the entities and structures defined in a knowledge model for design process of machining fixtures can be partially reused to develop new models for fixture design process, as the inspection or assembly fixture. The entities and structures reused has been defined using the method of knowledge template[4]. The work presented is a detailed proposition of the knowledge model for machining fixture design and the definition of the knowledge groups that can be reused in the inspection fixture design process, using the knowledge template method. Fig. 1 presents a general view of the contents of this ex Fig. 1. The structure of the work. planation. 2. Present state of fixture design process knowledge modelling The fixture concept arises from the need to establish a physical connection between part, and tool, and part and machine-tool. This connection should fulfil some requirements for support the machining operation to carry out. The mainly functionality of the fixture is to support, locate and clamp the part to the machine tool. However, in order to interpreting correctly the needed knowledge for develop the fixture design process, it is necessary to define the basic information related with this process according to the classification exposed in Table 1. All this information has been represented in models that describe the entities, attributes and relationships between each knowledge group in the fixture design process. The definition of these models can be carried out using methodologies that describe the activities to capture, represent and reuse the knowledge of a design system, for example MOKA and CommonKADS. The MOKA methodology is based on the definition of two models. These models allow to capture and to structure the knowledge of a system. The first model, uses a group of forms (ICARE: Illustrations, Constraints, Activities, Rules,Entities) that allow to capture and to represent the knowledge in a semistructured way; the second model allows to represent knowledge ina structured way, using the extension of UML [10]. The CommonKADS methodology proposes the use of tools and techniques to carry out the capture and representation of the knowledge. In the case of reusing knowledge, CommonKADS proposes the use of the knowledgetemplate: a knowledge template is a piece of a knowledge model, in which the data and reasoning processes can be employed in the development of other applications [3]. 3. Methodology for development a knowledge model: structural model The methodology proposed for development of a knowledge model includes the realization of two stages. The first stage represents the knowledgeof the objects like part geometry, machining process, functional and detailed fixture design,and fixture resources (see Table 1). The second stage describes the inference process (design and interpretation rules) needed to obtain a firstsolution for the machining fixture. These two stages allow to describe the structural model and behaviour model of the objects that compose the knowledge model for machining fixtures. This work is focused mainly in the descriptionof the structural model for machining fixture design process. Table 1 Knowledge group for machining fixture Knowledge group Characteristics Part geometry Geometry: holes, slots, etc. Dimensions Tolerances Machining process Type of machining process Machining phase and sub phase Machining operation Functional and detailed Methodology of design fixture design process Design rules Interpretation rules Design constrains Fixture resources Type of fixture (modular, general, or dedicated) (functional elements Type of fixture elements (support, locate, clamp) and commercial elements) Type of machine tool (vertical milling machine, horizontal milling machine, etc.) The proposed structural model contains a general structure of the knowledge groups related with the fixture design process. The description of theaspects related with the knowledge groups are presented in Table 1. Fig. 2 shows the general structure of the knowledge groups for machining fixture design process. Due to the complexity of the fixture design process, the fixture design cannot be considered as an independent process with respect to the manufacturing process. In this sense, the information of the manufacturing process isdirectly represented in the fixture design process. In a similarway, the resources involved in the manufacturing process have a narrow relationship with the fixture resources, in terms of machine tools and commercial elements of fixture. The definition of each knowledge groups (see Table 1) has taken into consideration the attributes and necessary operations to represent the knowledge relative to these knowledge groups. The applications of these models are presented in the following sections. Fig. 2. Structural model for machining fixture. 4. Knowledge template model In this section, we describe those pieces of the knowledge model thatcan be reused in other applications using the method of knowledge template.From a conceptual point of view, a knowledge template describes a piece of the knowledge model in which the i nference and the knowledge tasks are defined with the objective of reuse this knowledge in other similar applications. In this sense, it is necessary to distinguish among the analytic and the synthetic tasks. The analytic tasks define the classification of the objects involv Fig. 3. Knowledge tasks based on the structural model. ed in the fixture design process. The synthetic tasks have relationship with the reasoning way procedure from which a fixture solution is obtained. Using these two types of tasks, a first approach has been established to define the knowledge groups that can be classified under the analytic and synthetic tasks. Fig. 3 shows the objects of the structural model that describe the analytic and synthetic tasks of the machining fixture design process. The division of these two tasks allows to set in a first level the knowledge groups, that it objects and attributes that can be employed in the development of new applications. Also, this separation allows us to identify those knowledge groups that describe inference procedures in the design process,as the functional fixture design and the detailed fixture design. This section presentsthe definition of the tasks of the knowledge model classified under theconcept of analytic and synthetic tasks that can be reused in other applications. 4.1. Analytic task definition The entities (or classes) defined under this cat egory can be classified regarding the level of dependence level that present the objects involved in the machining fixture design. The first level defines those knowledge groups that are not consequence of the fixture design process, as geometry, dimensions and tolerances of the part. In this level, the entities that compose these knowledge groups can be totally reused in their structure, relationships and attributes. Fig. 4 shows an example of the knowledge group of geometry that can be reused in other applications. Fig. 4. Knowledge template for part entity (analytic task). The second level describes those entities that present a similar structure and relationships in the fixture design process(fixture functions and commercial elements for machining fixtures). In this level, can be reused only a portion of the structure and relationships that are not conditioned by the fixture design process. The third level describes those entities that present a complete dependence to the fixture design process. In this level, cannot be reused the knowledge previously defined (structures, relationships and attributes), due to dependence of the process developed. 4.2. Synthetic task definition The definition of the synthetic tasks involves the identification of those objects linked with the inference procedure carried out in the fixture design process. In this type of tasks, it cannot have a total reutilization of the knowledge, because the inference process carried out using a group of production rules that depend of the type of process executed. Under this classification, the knowledge group of functional design establish the functional solution of the fixture definition: the supporting surfaces,locating and clamping of the part. The definition of these surfaces is depending to the manufacturing process developed. This last characteristic makes thatthe functional design possesses depend of the machining processes developedduring the manufacturing of the part. In this sense, the sharing knowledge ofthis group is limited to the definition of the surfaces and supporting points, locating, clamping for machining fixture and to selection of the functional elements. However, the knowledge group of functional elements can be reused Fig. 5. Knowledge template for functional elements entity. in other applications, due to the functional elements can be employed in multiple domains in the fixture design process. Fig. 5 shows an example of the knowledge template for functional elements used in the fixture design process. In the detailed design occur similar situations to those of the functional design. In this case, the detailed design depends on the fixture functional design through a correspondence between functional and commercial elements.The knowledge group for fixture elements can be partially reused to define a new group of fixture elements. For it, we must use the structure, relationships and entities defined for the following categories, base, support, locate, clampand auxiliary elements. Table 2 Initial information for fixture machining Information Characteristics Initial geometr Final geometry Machining operations Face milling Side milling Drilling Manufacturing resources Vertical milling machine Fixture resources Modular fixture elements 5. Application of the knowledge model In the next two sections, we present the application of the knowledge model for machining and inspection fixture design. These models taking into consideration two different parts, because we wish express the potentiality of the use of knowledge template. The implementation of the structuralmodel,discussed in Section 3, isbased on the instantiation of each attribute defined defined in the knowledge groups that compose this model. The instantiation is defined as the assignment of a concrete value for a specific attribute. For it, the initial conditions are exposed for the application of the knowledge model, which include the description of the initial geometry, final geometry, lists of machiningoperations,machine-tool and fixture resources. Table 2 shows the initial information for the application of the knowledge model for machining fixture. Mechanical Engineering upon the principles of mechanics, such as those of static for reaction forces and for the optimum utiliza- tion of friction; of dynamics for inertia, acceleration, and energy; of elasticity and strength of materials for stress and deflection; of physical behavior of materials; and of fluid mechanics for lubrication and hydrodynamic drives. The analyses may be made by the same engineer who conceived the arrange- ment of mechanisms, or, in a large company, they may be made by a separate analysis division or research group. As a result of the analyses, new arrangements and new dimensions may be required. Design is a reiterative and cooperative process, whether done formally or informally, and the analyst can contribute to phases other than his own. Finally, a design based upon function and reli- ability will be completed, and a prototype may be built. If its tests are satisfactory, and if the device is to be produced in quantity, the initial design will undergo certain modifications that enable it to be manufactured in quantity at a lower cost. During subsequent years of manufacture and service, the design is likely to undergo changes as new ideas are conceived or as further analyses based upon tests and experience indicate alterations. Sales appeal, customer satisfaction, and manufacturing cost are all related to design, and ability in design is intimately involved in the success of an engineering venture. Some Rules for Design In this section it is suggested that, applied with a creative attitude, analyses can lead to important improvements and to the conception and perfec- tion of alternate, perhaps more functional, eco- nomical, and durable products. The creative phase need not be an initial and separate one. Although he may not be responsible for the whole design, an analyst can contribute more than the numerically correct answer to a problem that he is asked to solve—more than the values of stress, dimensions, or limitations of operation. He can take the broader view that the specifications or the arrangements may be improved. Since he will become familiar with the device and its conditions of operation be- fore or during his analysis, he is in a good position to conceive of alternatives. It is better that he suggest a change in shape that will eliminate a moment or a stress concentration than to allow construction of a mechanism with –heavy sections and excessive dynamic loads. It is better that he scrap his fine analysis, rather than that he later see the mechanism scrapped. To stimulate creative thought, the following rules are suggested for the designer and analyst. The first six rules are particularly applicable for the analyst, although he may become involved with all ten rules. 1. Apply ingenuity to utilize desired physical properties and to control undesired ones. 2. Recognize functional loads and their significance. 3. Anticipate unintentional loads. 4. Devise more favorable load- ing conditions. 5. Provide for favorable stress distribution and stiffness with minimum weight. 6. Use basic equations to proportion and opti- mize dimensions. 7. Choose materials for a combina- tion of properties. 8. Select carefully, between stock: and integral components. 9. Modify a functional design to fit the manu- facturing process and reduce cost. 10. Provide for accurate location and nonin- terference of parts in assembly. Machine Design The complete design of a machine is a complex process. The designer must have a good back- ground in such fields as static’s, kinematics, dy- namics, and strength of materials, and in addition, be familiar with the fabricating materials and proc- esses. The designer must be able to assemble all the relevant facts, and make calculations, sketches, and drawings to convey manufacturing information to the shop. One of the first steps in the design of any product is to select the material from which each part is to be made. Numerous materials are avail- able to today's designers. The function of the prod- uct, its appearance, the cost of the material, and the cost of fabrication are important in making a selec- tion. A careful evaluation of the properties of a. ma- terial must be made prior to any calculations. Careful calculations are necessary to ensure the validity of a design. Calculations never appear on drawings, but are filed away for several reasons. In case of any part failures, it is desirable to know what was done in originally designing the defective components. Also, an experience file can result from having calculations from past projects. When a similar design is needed, past records are of great help. The checking of calculations (and drawing di- mensions) is of utmost importance. The misplace- ment of one decimal point can ruin an otherwise acceptable project. For example, if one were to de- sign a bracket to support 100 lb when it should have been figured for 1,000 lb, failure would surely be forthcoming. All aspects of design work should be checked and rechecked. The computer is a tool helpful to mechanical designers to lighten tedious calculations, and pro- vide extended analysis of available data. Interactive systems, based on computer capabilities, have made po