裝配圖發(fā)動機飛輪殼加工工藝及其夾具設計
裝配圖發(fā)動機飛輪殼加工工藝及其夾具設計,裝配,發(fā)動機,飛輪,加工,工藝,及其,夾具,設計
畢業(yè)設計(論文)中期報告(學生用表)
姓名
陳立保
學號
20090130510
專業(yè)
機械設計制造及其自動化
院系
機械工程系
論文(設計)題目
發(fā)動機飛輪殼的加工工藝及其夾具設計
指導老師
葉仲新
開題報告(打√)
外文翻譯(打√)
工作進度(打√)
是否上交(√ ) 是否批改( √)
是否上交(√ ) 是否批改( )
超前( ) 正常(√ ) 滯后( )
學生填寫
課題簡介:本課題將針對湖北省十堰市東風商用車有限責任公司制造車間實際的發(fā)動機飛輪殼進行加工工藝及其夾具設計。
本課題的設計工作將緊緊圍繞工藝設計和夾具設計,充分運用所學的專業(yè)知識,并結合實習實踐,同時以AutoCAD和三維軟件UG為輔導進行計算機輔助設計,實現(xiàn)飛輪殼的三維建模和二維總裝圖。
按照任務書應完成的工作內(nèi)容與進展情況(文獻資料查閱、課題調(diào)研與實習、開題報告、外文翻譯、課題研究與設計、實施等):
1、 文獻資料查閱:為了高質(zhì)量完成該課題的設計,查閱了十幾篇中外文獻及論文,了解了該課題的國內(nèi)外最新研究情況。
2、 課題調(diào)研與實習:開學第一周在指導老師的帶領下參觀、調(diào)研了東風商用車發(fā)動機廠,對專用設備的制造有了較深刻的了解。并完成了實習報告。
3、 開題報告:第三周我在老師的指導下完成了開題報告。明確了設計內(nèi)容和重點、難點。
4、 外文翻譯:第五周完成了題目為《工藝規(guī)程制訂與并行工程》的外文翻譯。
5、 課題實施:已經(jīng)完成了康明斯系列發(fā)動機飛輪殼總體工藝設計方案選擇;運用AutoCAD開始繪制總裝配圖和部分零件圖。
課題存在的問題及解決辦法:
遇到的困難:
一、具體尺寸的確定:如零件圖尺寸的確定;
二、加工基準面、公差等級及位置精度的要求等等。
解決辦法是:
1、 通過圖紙的縮放來大致確定零件的各尺寸;
二、通過查閱有關資料和老師的幫助,確定基準面、公差等級及位置精度等,最終設計出合理的方案。
待完成的工作:
查閱相關資料,制定三個不同的加工工藝方案,并且確定最佳方案;
編寫發(fā)動機飛輪殼加工工藝及其夾具設計說明書;
撰寫畢業(yè)設計論文和準備答辯材料。
指導教師意見
指導教師: 年 月 日
注:此表裝入學生畢業(yè)論文(設計)資料袋存檔。
畢業(yè)設計(論文)任務書
課題名稱
發(fā)動機飛輪殼加工工藝及其夾具設計
系 部
機械工程系
專 業(yè)
機械設計制造及其自動化
班 級
T913-5
姓 名
陳立保
學 號
20090130510
任務起止日期
2013
年
1
月
15
日至
2013
年
5
月
25
日共
15
周
指導教師簽名(校內(nèi))
指導教師簽名(校外)
教學主任簽名
年
月
日
一、課題內(nèi)容
本課題來源于東風發(fā)動機部件有限公司的生產(chǎn)實際。設計一套年生產(chǎn)綱領為5萬輛份發(fā)動機飛輪殼的加工工藝規(guī)程及其機床夾具。發(fā)動機飛輪殼屬殼體零件,為滿足加工精度要求,可采用數(shù)控加工技術,在滿足工序定位要求的前提下,以保證各表面的位置精度要求,夾緊可靠,操作方便的機床夾具。
二、課題任務要求
要求學生具備較扎實的機械設計制造及其工藝與裝備方面的知識,有較強的機械設計和一定的分析問題、解決問題的能力。設計任務要求:
1.編寫畢業(yè)設計課題的開題報告一份。(3000字)2.翻譯課題相關的英文技術資料。(3000字以上)3.繪制發(fā)動機飛輪殼零件圖,進行結構工藝性分析。4.擬定汽車發(fā)動機飛輪殼加工方案。5.繪制發(fā)動機飛輪殼的毛坯圖。6.對發(fā)動機飛輪殼的加工工藝方案進行分析得出結論。7.編寫發(fā)動機飛輪殼機械加工工藝卡一份。 8.繪制發(fā)動機飛輪殼機床夾具總裝配圖及其主要零件圖。9.編寫畢業(yè)設計說明書一份(15000字以上)。
三、進程安排
序號
畢業(yè)設計各階段內(nèi)容
日 期
1
明確設計任務、查閱收集相關資料、調(diào)研、實習。
1.14~2.28
2
編寫、修改、上交畢業(yè)設計開題報告。(3000字以上)
3.1~3.11
3
翻譯、上交英文技術資料。(3000字以上)
3.1~4.1
4
繪制汽車發(fā)動機飛輪殼零件圖,進行結構工藝性分析
擬定汽車發(fā)動機飛輪殼機械加工方案。
3.1~3.10
5
選擇發(fā)動機飛輪殼毛坯制造方法,繪制毛坯圖。
3.11~3.15
6
制定發(fā)動機飛輪殼的加工工藝路線,繪制工藝路線流程圖。
3.16~4.15
7
編寫發(fā)動機飛輪殼機械加工工藝卡。
4.16~5.15
8
繪制發(fā)動機飛輪殼機床夾具總裝配圖及其主要零件圖。
5.16~5.22
9
編寫畢業(yè)設計說明書一份。(15000字)
整理、上交畢業(yè)設計全部資料。
5.23~5.26
10
總結,準備畢業(yè)設計答辯。
5.27~6.2
四、應閱讀的主要參考文獻
[1] 唐金松主編.簡明機械設計手冊[M].上海:上??茖W技術出版社,2000
[2] 候家駒主編.汽車制造工藝學[M].北京:機械工業(yè)出版社,1991
[3] 劉友才等主編.機床夾具設計[M]. 北京:機械工業(yè)出版社,1994
[4] 大連組合機床研究所主編.組合機床設計[M].北京:機械工業(yè)出版社,1978
[5] 李鐵堯主編.金屬切削機床[M].北京:機械工業(yè)出版社,1993
[6] 孟少農(nóng)主編.機械加工工藝手冊[M].北京:機械工業(yè)出版社,1992
[7] 大連組合機床研究所編寫.組合機床設計(第一冊)[M].北京:機械工業(yè)出版社,1975
畢業(yè)設計(論文)參考文獻譯文
學生姓名: 陳立保
系 別: 機 械 工 程 系
專 業(yè): 機械設計制造及其自動化
班 級: T913-5
學 號: 20090130510
譯文出處: 百度文庫
課題:發(fā)動機飛輪殼的加工工藝及其夾具設計
Process Planning and Concurrent Engineering
T. Ramayah and Noraini Ismail
The product design is the plan for the product and its components and subassemblies.To convert the product design into a physical entity ,a manufacturing plan is needed .The activity of developing such a plan is called process planning .It is the link between product design and manufacturing .Process planning involves determining the sequence of processing and assembly steps that must be accomplished to make the product .In the present chapter ,we examine processing planning and several related topics.
At the outset ,we should distinguish between process planning and production planning ,which is covered in the following chapter. Process planning is concerned with the engineering and technological issues of how to make the products and its parts. What types of equipment and tooling are required to fabricate the parts and assemble the product ? Production planning is concerned with the logistics of making the product .After process planning is concerned with ordering the materials and obtaining the resources required to make the product in sufficient quantities to satisfy demand for it.
Process Planning
Process planning involves determining the most appropriate manufacturing and assembly processes and the sequence in which they should be accomplished to produce a given part or product according to specifications set forth in the product design documentation.The scope and variety of processes that can be planned are generally limited by the available processing equipment and technological capabilities of the company of plant .Parts that cannot be made internally must be purchased from outside vendors. It should be mentioned that the choice of processes is also limited by the details of the product design.This is a point we will return to later.
Process planning is usually accomplished by manufacturing engineers .(Other titles include in industrial engineer.) The process planner must be familiar with the particular manufacturing processes available in the factory and be able to interpret engineering drawings .Based on the planner’s knowledge,skill,and experience ,the processing steps are developed in the most logical sequence to make each part .Following is a list of the many decisions and details usually include within the scope of process planning :
.Interpretation of design drawings. The part of product design must be analyzed (materials,dimensions,tolerances ,surface finished,etc.) at the start of the process planning procedure.
.Process and sequence. The process planner must select which processes are required and their sequence.A brief description of processing steps must be prepared.
.Equipment selection . In general , process planners must develop plans that utilize existing equipment in the plant .Otherwise ,the component must be purchased ,or an investment must be made in new equipment .
.Tools ,dies,molds,fixtures,and gages. The process must decide what tooling is required for each processing step.The actual design and fabrication of these tools is usually delegated to a tool design department and tool room ,or an outside vendor specializing in that type of tool is contacted.
Methods analysis . Workplace layout ,small tools ,hoists for lifting heavy parts ,even in some cases hand and body motions must be specified for manual operations .The industrial engineering department is usually responsible for this area.
.Work standards. Work measurement techniques are used to set time standards for each operation .
.Cutting tools and cutting conditions. These must be specified for machining operations ,often with reference to standard handbook recommendations.
Process Planning for parts
For individual parts,the processing sequence is documented on a form called a route sheet .(Not all companies use the name route sheet ;another name is “operation sheet .”)Just as engineering drawings are used to specify the product design ,route sheets are used to specify the process plan .They are counterparts,one for product design ,the other for manufacturing .
A typical processing sequence to fabricate an individual part consists of : (1) a basic process,(2)secondary processes ,(3) operations to enhance physical properties,and (4)finishing operations.The sequence is shown in Fig.21.2. A basic process determines the starting geometry of the workpart.Metal casting ,plastic molding ,and roling of sheet metal are examples of basic processes.The starting geometry must often be refined by secondary processes,operations that transform the starting geometry (or close to final geometry ).The secondary geometry processes that might be used are closely correlated to the basic process that provides the starting geometry.When sand casting is the basic processes,machining operations are generally the second processes .When a rolling mill produces sheet metal,stamping operations such as punching and bending are the secondary processes.When plastic injection molding is the basic process ,secondary operations are often unnecessary,because most of the geometric features that would otherwise require machining can be created by the molding operation.Plastic molding and other operation that require no subsequent secondary processing are called net shape processes.Operations that require some but not much secondary processing (usually machining ) are referred to as near net shape processes.Some impression die forgings are in this category .These parts can often be shaped in the forging operation(basic processes)so that minimal machining (secondary processing )is required .
Once the geometry has been established ,the next step for some parts is to improve their mechanical and physical properties .Operations to enhance properties do not alter the geometry of the part;instead,they alter physical properties .Heat treating operations on metal parts are the most common examples .Similar heating treatments are performed on glass to produce tempered glass.For most manufactured parts ,these property-enhancing operations are not required in the processing sequence .
Finally finish operations usually provide a coat on the work parts (or assembly )surface. Examples inclued electroplating ,thin film deposition techniques ,and painting.The purpose of the coating is to enhance appearance ,change color ,or protect the surface from corrosion,abrasion ,and so forth .Finishing operations are not required on many parts ;for example, plastic molding rarely require finishing .When finishing is required ,it is usually the final step in the processing sequence .
Processing Planning for Assemblies
The type of assembly method used for a given product depends on factors such as : (1) the anticipated production quantities ;(2) complexity of the assembled product ,for example ,the number of distinct components ;and (3)assembly processes used ,for example ,mechanical assembly versus welding .For a product that is to be made in relatively small quantities ,assembly is usually performed on manual assembly lines .For simple products of a dozen or so components,to be made in large quantities ,automated assembly systems are appropriate .In any case ,there is a precedence order in which the work must be accomplished .The precedence requirements are sometimes portrayed graphically on a precedence diagram.
Process planning for assembly involves development of assembly instructions,but in more detail .For low production quantities,the entire assembly is completed at a single station .For high production on an assembly line ,process planning consists of allocating work elements to the individual stations of the line, a procedure called line balancing.The assembly line routes the work unit to individual stations in the proper order as determined by the line balance solution.As in process planning for individual components ,any tools and fixtures required to accomplish an assembly task must be determined ,designed,and built;and the workstation arrangement must be
laid out.
Make or Buy Decision
An important question that arises in process planning is whether a given part should be produced in the company’s own factory or purchased from an outside vendor ,and the answer to this question is known as the make or buy decision .If the company does not possess the technological equipment or expertise in the particular manufacturing processes required to make the part ,then the answer is obvious: The part must be purchased because there is no internal alternative .However ,in many cases ,the part could either be made internally using existing equipment ,or it could be purchased externally from a vendor that process similar manufacturing capability.
In our discussion of the make or buy decision ,it should be recognized at the outset that nearly all manufactures buy their raw materials from supplies .A machine shop purchases its starting bar stock from a metals distributor and its sand castings from a foundry .A plastic molding plant buys its molding compound from a chemical company.A stamping press factory purchases sheet metal either fro a distributor or direct from a rolling mill.Very few companies are vertically integrated in their production operations all the way from raw materials ,it seems reasonable to consider purchasing at least some of the parts that would otherwise be produced in its own plant.It is probably appropriate to ask the make or buy question for every component that is used by the company .
There are a number of factors that enter into the make or buy decision .We have complied a list of the factors and issues that affect the decision in Table 21-3 .One would think that cost is the most important factor in determining whether to produce the part or purchase it .If an outside vendor is more proficient than the company’s own plant in the manufacturing processes used to make the part ,then the internal production cost is likely to be greater than the purchase price even after the vendor has included a profit .However ,if the decision to purchase results in idle equipment and labor in the company’s own plant ,then the apparent advantage of purchasing the part may be lost .Consider the following example .Example 21.1 Make or Buy Decision
The quoted price for a certain part is $20.00 per unit for 100 units .The part can be produced in the company’s own plant for $28.00. The components of making the part are as follows :
Unit raw material cost = $8.00 per unit
Direct labor cost =6.00 per unit
Labor overhead at 150%=9.00 per unit
Equipment fixed cost =5.00 per unit
________________________________
Total =28.00 per uniit
Should the component by bought or made in-house?
Solution :Although the vendor’s quote seems to favor a buy decision ,let us consider the possible impact on plant operations if the quote is accepted.Equipment fixed cost of $5.00 is an allocated cost based on investment that was already made .If the equipment designed for this job becomes unutilized because of a decision to purchase the part ,then the fixed cost continues even if the equipment stands idle .In the same way ,the labor overhead cost of $9.00 consists of factory space ,utility ,and labor costs that remain even if the part is purchased .By this reasoning ,a buy decision is not a good decision because it might be cost the company as much as $20.00+$5.0+$9.00=$34.00 per unit if it results in idle time on the machine that would have been used to produce the part .On the other hand ,if the equipment in question can be used for the production of other parts for which the in-house costs are less than the corresponding outside quotes ,then a buy decision is a good decision .,
Make or buy decision are not often as straightforward as in this example .The other factors listed in Table 21-3also affect the decision .A trend in recent years ,especially in the automobile industry ,is for companies to stress the importance of building close relationships with parts suppliers .We turn to this issue in our later discussion of concurrent engineering.
Computer-aided Process Planning
There is much interest by manufacturing firms in automating the task of process planning using computer-aided process planning (CAPP) systems .The shop-trained people who are familiar with the details of machining and other processes are gradually retiring ,and these people will be available in the future to do process planning .An alternative way of accomplishing this function is needed ,and CAPP systems are providing this alternative .CAPP is usually considered to be part of computer-aided manufacturing (CAM) .However ,this tends to imply that CAM is a stand-along system .In fact ,a synergy results when CAM is combined with computer-aided design to create a CAD/CAM system .In such a system ,CAPP becomes the direct connection between design and manufacturing .The benefits derived from computer-automated process planning include the following:
.Process rationalization and standardization .Automated process planning leads to more logical and consistent process plans than when process is done completely manually .Standard plans tend to result in lower manufacturing costs and higher product quality.
.Increased productivity of process planner . The systematic approach and the availability of standard process plans in the data files permit more work to be accomplished by the process planners.
.Reduced lead time for process planning . Process planner working with a CAPP system can provide route sheets in a shorter lead time compared to manual preparation .
.Improved legibility . Computer-prepared rout sheets are neater and easier to read than manually prepared route sheets.
.Incorporation of other applicaton programs. The CAPP program can be interfaced with other application programs,such as cost estimating and work standards.
Computer-aided process planning systems are designed around two approaches.These approaches are called : (1) retrieval CAPP systems and (2) generative CAPP systems .Some CAPP systems combine the two approaches in what is known as semi-generative CAPP.
Concurrent Engineering and Design for Manufacturing
Concurrent engineering refers to an approach used in product development in which the functions of design engineering ,manufacturing engineering ,and other functions are integrated to reduce the elapsed time required to bring a new product to market, Also called simultaneous engineering ,it might be thought of as the organizational counterpart to CAD/CAM technology.In the traditional approach to launching a new product ,the two functions of design engineering and manufacturing engineering tend to be separated and sequential,as illustrated in Fig.21.3.(a).The product design department develops the new design ,sometimes without much consideration given to the manufacturing capabilities of the company ,There is little opportunity for manufacturing engineers to offer advice on how the design might be alerted to make it more manufacturable.It is as if a wall exits between design and manufacturing.When the design engineering department completes the design ,it tosses the drawings and specifications over the wall ,and only then does process planning begin.
Product design
Manufacturing engineering and process planning
Production and assembly
The “wall” between design and manufaturing
Product launch time,traditional design/manufacturing cycle
Difference in product launch time
(a)Traditional product development cycle
Product design
Sales and marketing
Quality engineering
Vendors
Manufacturing engineering and process planning
Production and assembly
Product lauch time,concurrent engineering
(b) product development using concurrent engineering
Fig.21.3 Comparison : (a) traditional product development cycle and (b) product development using concurrent engineering
By contrast,in a company that practices concurrent engineering ,the manufacturing engineering department becomes involved in the product development cycle early on ,providing advice on how the product and its components can be designed to facilitate manufacture and assembly.It also proceeds with early stages of manufacturing planning for the product .This concurrent engineering approach is pictured in Fig.21.3(b). In addition to manufacturing engineering ,other function are also involved in the product development cycle ,such as quality engineering ,the manufacturing departments ,field service ,vendors supplying critical components ,and in some cases the customer who will use the product .All if these functions can make contributions during product development to improve not only the new product’s function and performance,but also its produceability ,inspectability ,testability ,serviceability ,and maintainability .Through early involvement ,as opposed to reviewing the final product design after it is too late to conveniently make any changes in the design ,the duration of the product development cycle is substantiallly reduced.
Concurrent engineering includes several elements: (1) design for several manufacturing and assembly,(2) design for quality ,(3)design for cost ,and (4) design for life cycle .In addition ,certain enabling technologies such as rapid prototyping ,virtual prototyping ,and organizational changes are required to facilitate the concurrent engineering approach in a company.
Design for Manufacturing and Assembly
It has been estimated that about 70% of the life cycle cost of a product is determined by basic decisions made during product design. These design decisions include the material of each part,part geometry,tolerances, surface finish,how parts are organized into subassemblies,and the assembly methods to be used.Once these decisions are made ,the ability to reduce the manufacturing cost of the product is limited.For example ,if the product designer decides that apart is to be made of an aluminum sand casting but which processes features that can be achieved only by machining(such as threaded holes and close tolerances), the manufacturing engineer has no alternative expect to plan a process sequence that starts with sand casting followed by the sequence of machining operations needed to achieve the specified features .In this example, a better decision might be to use a plastic molded part that can be made in a single step .It is important for the manufacturing engineer to be given the opportunity to advice the design engineer as the product design is evolving, to favorably influence the manufacturability of the product.
Term used to describe such attempts to favorably influence the manufacturability of a new product are design for manufacturing (DFM) and design for assembly(DFA). Of course ,DFM and DFA are inextricably linked ,so let us use the term design for manufacturing and assembly (DFM/A).Design for manufacturing and assembly involves the systematic consideration of manufacturability and assemblability in the development of a new product design .This includes: (1) organizational changes and (2)design principle and guidelines.
Organizational Changes in DFM/A. Effective implementation of DFM/A involves making changes in a company’s organization structure ,either formally or informally ,so that closer interaction and better communication occurs between design and manufacturing personnel.This can be accomplished in several ways : (1)by creating project teams consisting of product designers, manufacturing engineers ,and other speclaities (e.g, quality
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