軸承內(nèi)外圈加工專用機床上料機構設計【含CAD圖紙】

喜歡這套資料就充值下載吧。資源目錄里展示的都可在線預覽哦。下載后都有，請放心下載，文件全都包含在內(nèi)，【有疑問咨詢QQ:414951605 或 1304139763】=喜歡這套資料就充值下載吧。資源目錄里展示的都可在線預覽哦。下載后都有，請放心下載，文件全都包含在內(nèi)，【有疑問咨詢QQ:414951605 或 1304139763】= 編號無錫太湖學院畢業(yè)設計（論文）相關資料題目： 軸承內(nèi)外圈加工專用 機床上料機構設計 信機 系 機械工程及自動化專業(yè)學 號： 0923248學生姓名： 周唐燕 指導教師： 彭勇 （職稱：副教授 ） （職稱： ）2013年5月25日目 錄一、畢業(yè)設計（論文）開題報告二、畢業(yè)設計（論文）外文資料翻譯及原文三、學生“畢業(yè)論文（論文）計劃、進度、檢查及落實表”四、實習鑒定表無錫太湖學院畢業(yè)設計（論文）開題報告題目： 軸承內(nèi)外圈加工專用 機床上料機構設計 信機 系 機械工程及自動化專業(yè)學 號： 0923248 學生姓名： 周唐燕 指導教師： 彭勇 （職稱：副教授 ） （職稱： ）2012年 11 月 25日 課題來源該課題來源于迪奧企業(yè)軸承內(nèi)外圈加工的需求?？茖W依據(jù)（包括課題的科學意義；國內(nèi)外研究概況、水平和發(fā)展趨勢；應用前景等）（1）課題的科學意義本課題研究的意義在于：軸承內(nèi)外圈加工專用機床上料裝置，屬于工件上料裝置，現(xiàn)有技術實現(xiàn)上料托與壓料部協(xié)調(diào)動作的機械傳動機構結構復雜、且在動作過程因磨損而影響上料托與壓料部協(xié)調(diào)動作的精確性，本實用新型包括上料氣缸和由上料氣缸驅動的滑板，所述的滑板上設置有上料托，其特征是所述的滑板上連接有一個壓料氣缸，由該壓料氣缸驅動一個壓料滑塊，該壓料滑塊上設置一個與所述上料托對應的壓料部。本實用新型省略了結構復雜的機械傳動機構，通過兩個動力分別驅動上料托和壓料部，便于通過程序控制器對上料氣缸和壓料氣缸的控制，實現(xiàn)上料托與壓料部的協(xié)調(diào)動作，在簡化了結構的同時，也保證上料托與壓料部動作協(xié)調(diào)的精確性。（2）國內(nèi)外研究狀況、水平和發(fā)展趨勢美國麻省理工學院1952年研制出第一臺實驗性數(shù)控系統(tǒng)，距現(xiàn)在已歷經(jīng)半個世紀。我國數(shù)控技術的發(fā)展得益于改革開放。20世紀80年代開始，先后從美國、日本、德國等發(fā)達國家引進了一些數(shù)控系統(tǒng)和伺服技術。陸續(xù)發(fā)展了一批具有70 年代末、80年代初期水平的數(shù)控系統(tǒng)，這些系統(tǒng)較完善的性能和穩(wěn)定性，很快得到了用戶的認可，結束了我國數(shù)控機床發(fā)展長期徘徊不前的局面，推動了我國數(shù)控機床的發(fā)展。90年代，我國的數(shù)控機床技術得到了較大提升。數(shù)控機床的核心技術數(shù)控系統(tǒng)和伺服驅動系統(tǒng)，也由完全依賴進口，發(fā)展到引進消化、自主開發(fā)階段。目前我國有數(shù)十家研究所或企業(yè)能夠從事各種類型數(shù)控系統(tǒng)的生產(chǎn)與研制。比較有代表性的，如北京的KND系統(tǒng)、DKM系統(tǒng)、南京的華興系統(tǒng)、新方達系統(tǒng)、華中理工大學的華中系統(tǒng)、成都的廣泰系統(tǒng)等。 該機床主要用于汽車行業(yè)、軍工行業(yè)和其他工業(yè)行業(yè)的軸承生產(chǎn)制造，實現(xiàn)了單機自動化、多機線自動化的生產(chǎn)制造。其中軸承行業(yè)，占據(jù)頂端市場份額的90以上，速度、準確度和耐用性是我們的產(chǎn)品成功要素。研究內(nèi)容 分析原始資料，查閱相關資料，收集整理有關上料機構設計、完成工藝、設備、機械加工等的資料。 對機床進行系統(tǒng)分析以及功能分析，并在此基礎上確定軸承內(nèi)外圈上料機構的設計方案。 完成上料機構的整體設計，各個零件的建模和整體的裝配，最后進行上料機構的運動仿真。 完成設計說明書及一篇外文翻譯。擬采取的研究方法、技術路線、實驗方案及可行性分析（1）研究方法借閱相關書籍雜志，充分利用圖書館及網(wǎng)絡資源。（2）技術路線收集資料，確定方案，設計尺寸，三維建模，運動仿真。（3）實驗方案首先研究軸承內(nèi)外圈車加工專用車床的整體結構，設計一個符合要求的整體裝配結構；其次根據(jù)性能要求進行校核；然后對強度進行有效的分析處理，并根據(jù)其處理結果進行有效的選擇；最后將選擇最適合的材料完成整個上料機構的設計。（4）可行性分析 查閱相關設計資料，了解設計過程。熟悉零件各種配合方式和參數(shù)的計算， 熟練運用AutoCAD軟件和UG軟件，做出機械零件和裝配圖以及三維建模和 運動仿真。最后整理資料，完成畢業(yè)設計論文。研究計劃及預期成果研究計劃：2012年11月12日-2012年12月2日：收集資料，撰寫開題報告、文獻綜述；2013年3月4日-2013年3月15日：完成零件三維造型，確定工藝總體方案；2013年3月18日-2013年3月22日：完成上料機構的裝配；2013年3月25日-2013年3月29日：完成上料機構的全部零件圖；2013年4月1日-2013年4月12日：完成上料機構的總裝圖及運動仿真；2013年4月15日-2013年4月28日：完成上料機構設計的說明書和相關資料的 撰寫；2013年5月2日-2013年5月10日：詳細審閱設計計算、說明書及圖紙并修改；2013年5月13日-2013年5月25日：遞交畢業(yè)設計資料，準備答辯材料，并 進行答辯。預期成果：設計中各個部件的選擇需要具體分析和理論計算，方案擬定正確；設計計算根據(jù)來源可靠，計算數(shù)據(jù)準確無誤，定位夾緊元件選用正確規(guī)范；機械結構圖紙繪制要求視圖完整、符合最新國家標準，圖面整潔、質(zhì)量高（圖紙繪制要求采用計算機繪圖）；用UG完成上料機構的所有零件建模和裝配，用CAD完成零件圖和組裝圖；基于UG進一步完成運動仿真。特色或創(chuàng)新之處 基于軸承領域用途廣泛，所以該機床的市場很大。 結構比原先的更簡單，使機器作業(yè)更便捷更安全。 使用了上料機構，效率更高。已具備的條件和尚需解決的問題 可以利用圖書館及網(wǎng)絡資源，已學過UG的基礎知識； 使用UG的運動仿真有待加強。指導教師意見 指導教師簽名：年 月 日教研室（學科組、研究所）意見 教研室主任簽名： 年 月 日系意見 主管領導簽名： 年 月 日英文原文Cylinder block machining process designEngine parts engine block is a more complex structure of spare parts box, its high precision, complex process, and the processing quality will affect the overall performance engine, so it has become the engine manufacturers focus parts one.1.Technical Characteristics of the engine cylinder blockCylinder cast for a whole structure, and its upper part 4 cylinder mounting hole;cylinder standard cylinder is divided into upper and lower divisions into two parts;cylinder to the rear of the front-side arrangement of the previous three coaxial mounting hole of the camshaft and the idler axle hole.Cylinder process features are: the structure of complex shape; processing plane,more than holes; uneven wall thickness and stiffness is low; processing of high precision typical of box-type processing part. The main processing of the surface of cylinder block top surface, the main bearing side, cylinder bore, the main and camshaft bearing bore holes and so on, they will directly affect the machining accuracy of the engine assembly precision and performance, mainly rely on precision equipment, industrial fixtures reliability and processing technology to ensure the reasonableness.2.Engine block process design principles and the basis forDesign Technology program should be to ensure product quality at the same time,give full consideration to the production cycle, cost and environmental protection;based on the enterprises ability to actively adopt advanced process technology and equipment, and constantly enhance their level of technology. Engine block machining process design should follow the following basic principles:(1) The selection of processing equipment ,the principle of selection adopted the principle of selection adopted the principle of combining rigid-flexible, processing each horizontal machining center is located mainly small operations with vertical machining center, the key process a crank hole, cylinder hole, balancer shaft hole High-speed processing of high-precision horizontal machining center, an upper and ower non-critical processes before and after the four-dimensional high-efficiency rough milling and have a certain adjustment range of special machine processing;(2) focus on a key process in principle process the body cylinder bore, crankshaft hole, Balance Shaft hole surface finishing and the combination of precision milling cylinder head, using a process focused on a setup program to complete all processing elements in order to ensure product accuracy The key quality processes to meet the cylinder capacity and the relevant technical requirements;According to the technological characteristics of automobile engine cylinder block and the production mandate, the engine block machining automatic production line is composed of horizontal machining center CWK500 and CWK500D machining centers, special milling/boring machine, vertical machining centers matec-30L and other appliances.(3) top and bottom, and tile covered only the combination of aperture rough milling machine dedicated to this machine to double-sided horizontal milling machine, using moving table driven parts, machine tools imported Siemens S7-200PLC system control, machine control cabinet set up an independent, cutting automate the process is completed and two kinds of automatic and adjust the state;(4) high-speed horizontal machining center machining center can be realized CWK500 the maximum flow of wet processing, but because of equipment, automatic BTA treatment system through the built-in tray under the wide-type chip conveyor and the completion of the machining center can be dry processing; machine tool spindle speed 6000r/min,rapid feeding speed 38m/min;(5) The combination of front and rear face rough milling machine tool using hydraulic transmission; control system imported Siemens S7-200PLC system control,machine tools have a certain flexibility;(6) The special machine TXK1500 this machine vertical machining center by the modification of shape, with vertical machining center features and performance,this machine has high strength, high wear-resistant, high stability, high accuracy, high-profile etc.;(7) high-speed vertical machining center matec-30L of the machining center spindle high speed 9000r/min.Control system uses Siemens SINUMERIK840D control system;(8) high-speed horizontal machining center spindle CWK500Dhighest speed15000r/min.3.Engine block machining process design the main contentEngine block complex structure, high precision, arge size, is thin-walled parts,there are a number of high precision plane and holes. Engine block machining process characteristics; mainly flat and the hole processing, processing of flat generally useplaning, milling methods such as processing, processing of hole used mainly boring,processing and multi-purpose drilling holes. As the cylinder complex structure. So how to ensure that the mutual position of the surface processing precision is an important issue.3.1 The selection of blankEngine block on the materials used are generally gray cast iron HT150,HT200,HT250,there is also cast aluminum or steel plate, this engine block using high-strength alloy cast iron. Cylinder in the processing prior to aging treatment in order to eliminate stress and improve the rough casting mechanical properties.Improve the rough accuracy, reduction of machining allowance, is to improve the automated production line system productivity and processing quality of the important measures. As the foreign box-type parts of rough quality and high precision, and its production-line system has been implemented directly on the blank line, not only eliminating the need for blank check device also saves the rough quality problems due to waste of machining time, increase overall efficiency. Therefore, the refinement of rough is to improve the productivity of the most promising way out. For the engine block production line, can be rough in parts on-line pre-milling six face, removing most of the margin, to facilitate direct on-line parts.3.2 Machining process selection and processing of the benchmarkChoose the right processing technology base is directly related to the processing quality can ensure the parts. Generally speaking, process benchmarking can be divided into coarse and fine reference base.(1) The baseline for the on-line thick rough, which is particularly important the choice of benchmark crude, if crude benchmark choice unreasonable, will the uneven distribution of machining allowance, processing and surface offsets, resulting in waste.In the cylinder production line, we have adopted for the coarse side of the base;(2) Refined the base of this box for the engine block parts, the general use of side two sales for a full range of uniform benchmarks, For the longer automated production positioning, therefore, will be divided into 2-3 segment pin holes used. In the cylinder pin hole of the process, we have adopted to the side, bottom and the spindle hole positioning, in the processing center on the process.3.3 Machining Processing Stages and processes of the arrangementsOften a part of many apparent need for processing, of course, the surface machining accuracy are different. Processing of high precision surface, often after repeated processing; As for the processing of the surface of low precision, only need to go through one or two on the list. Thus, when the development process in order to seize the processing high precision surface, this conflict, the reasonable arrangement processes and rational division stage of processing. Arrange the order of the principle of process is: after the first coarse refined, the first surface after the hole,the first benchmark other. In the engine block machining, the same should follow this principle.(1) roughing stage engine block machining process, the arrangements for roughing process, to fully carry out rough rough, trim most of the margin in order to ensure production efficiency;(2) semi-finishing phase of the engine block machining, in order to ensure the accuracy of the middle of some important surface processing, and arrange some semi-finishing operations, will be required accuracy and surface roughness of the surface of the middle of some processing to complete, while demanding the surface of semi-finished, to prepare for future finishing;(3) The finishing stage of requiring high accuracy and surface roughness of the surface processing;(4) secondary processing, such as small surface screw holes, you can finish of the major surface after the one hand, when the workpiece deformation process little impact at the same time also reduced the rejection rate;In addition,if the main surface of a waste,these small the surface will not have to be processed,thus avoiding a waste of man-hours.However,if the processing is very easy for a small surface bumps the main surface,it should be placed on a small surface finish prior to the main surface finishing;(5) should make proper arrangements for secondary processes such as product inspection process,in part roughing stage,the key process before and after processing,spare parts all the processing has been completed,should be appropriate arrangements.Stage of processing division,has the following advantages:First,it can take measures to eliminate the rough workpiece after the stress,to ensure accuracy;second,finishing on the back,and will not damage during transport the surface of the workpiece has been processed;again,first roughing the surface defects can be detected early and promptly deal with rough,do not waste working hours.But most small parts,do not sub very thin.3.4 cylinder surface of the main processing and secondary processesCylinder surface and support the main processing operations are:(1) plane processing at present, the milling of engine blocks is the primary means of planar processing,domestic milling feed rate is generally 300-400mm/min,and foreign 2000-4000mm/min milling feed rate compared to far cry,to be on increasing,therefore,improve the milling feed rate,reduce overhead time is to improve the productivity of the major means of finishing a number of plane engine block when the milling feed rate to reach 2399mm/min,greatly improved efficiency;Top surface of the cylinder milling is a key process in the process,the flatness requirements for 0.02/145mm,the surface roughness of Ra1.6um.Processing in the cylinder,the use of side and spindle bearing bore positioning,top,bottom and middle vagay only aperture while processing used in the processing line outside of the knife device can better meet the engine block machining accuracy;(2) General holes machining holes in general are still using the traditional processing of drilling,expansion,boring,reaming,tapping and other craft approach.Issues in the design process of specific programs,use of coated cutting tools,cutting tools and other advanced tools within the cooling,and using a large flow of cooling systems,greatly improving the cutting speed,improved productivity;(3) deep hole processing of the traditional processing method is used to grade twist drill feed,low efficiency of their production,processing and quality is poor.The deep hole in the engine block processing,the use of gun drilling process;(4) The three-axis machining holes for the cylinder-axis machining holes holes of high precision,long working hours of the restrictive process.Thus,work arrangements,processing methods,tools and so on should be special attention.All cover pre-processing,that is,semi-circular hole and the cylinder block main bearing cap of the shortage of processing,its main purpose is to remove blank margin,release stress,to prepare for the post-order processing;in crankshaft machining processing center hole,using double-sided Boring,boring the first holes in the crankshaft hole at one end to 1/2 length,and then turn 180 degrees workbench,form the other end and then bore another 1/2 length.(5) The cylinder bore machining cylinder hole cylinder machining processing is a key process in the one,under normal circumstances,the machining process as a rough boring,semi-fine boring,precision boring and honing.Cylinder bore wall for the early detection of casting defects,eliminate stress,should be thick cylinder boring holes in advance;due to the structural characteristics of the different cylinder bore,must be in honing process to improve the cylinder bore surface quality.In the high-volume production,the cylinder bore honing generally use the multi-axis grinding machine or honing Automatic Line.Here we use honing automatic lines,from the coarse-heng.Fine-heng and testing equipment,composed of three;(6) Cleaning cleaning is divided into wet cleaning and dry cleaning.Machining cylinder automatic production line using a large flow of wet cleaning; (7) Detect points outside the line detection and line detection of two kinds. Quality inspection in the engine block,according to the actual situation with lines outside the detection,the main use of coordinate measuring machine integrated measurements of the cylinder,each 200 samples 1-5 pieces,each class random one.4.SummaryThrough the engine block of the structure and process characteristics of the analysis,discusses the engine block machining process design principles and basis of the choice of cutting parameters,and U-turn at high speed milling and boring,for example,design,analysis of the engine cylinder body of high-speed milling and turnover boring process,and in the processing need to pay attention to.中文譯文缸體機械加工工藝設計發(fā)動機缸體是發(fā)動機零件中結構較為復雜的箱體零件，其精度要求高，加工工藝復雜，并且加工加工質(zhì)量的好壞直接影響發(fā)動機整個機構的性能，因此，它成為各個發(fā)動機生產(chǎn)廠家所關注的重點零件之一。1. 發(fā)動機缸體的工藝特點缸體為一整體鑄造結構，其上部有4個缸套安裝孔；缸體的水平隔板將缸體分成上下兩部分；缸體的前端面從到后排列有三個同軸線的凸輪軸安裝孔和惰輪軸孔。缸體的工藝特點是：結構、形狀復雜；加工的平面和孔比較多；壁厚不均，剛度低；加工精度要求高，屬于典型的箱體類加工零件。缸體的主要加工表面有頂面、主軸承側面、缸孔、主軸承孔及凸輪軸孔等，它們的加工精度將直接影響發(fā)動機的裝配精度和工作性能，主要依靠設備進度、工夾具的可靠性和加工工藝的合理性來保證。2. 發(fā)動機缸體工藝方案設計原則和依據(jù)設計工藝方案應在保證產(chǎn)品質(zhì)量的同時，充分考慮生產(chǎn)周期、成本和環(huán)境保護；根據(jù)本企業(yè)能力，積極采用國內(nèi)外先進的工藝技術和裝備，不斷提高企業(yè)工藝水平。發(fā)動機缸體機械加工工藝設計應遵循以下基本原則：（1）加工設備選型原則 加工設備選型采用剛柔結合的原則，加工設備以臥式加工中心為主，少量采用立式加工中心，關鍵工序曲軸孔、缸孔、平衡軸孔加工采用高精度高速臥式加工中心，非關鍵工序上下前后四個平面的粗銑采用高效并有一定調(diào)整范圍的專用機床加工；（2）集中工序原則 關鍵工序曲軸孔、缸孔、平衡軸孔的精加工缸蓋結合面的精銑，采用在集中在一道工序一次裝夾完成全部加工內(nèi)容方案，以確保產(chǎn)品精度滿足缸體關鍵品質(zhì)的工藝性能和有關技術要求。根據(jù)汽車發(fā)動機缸體的工藝特點和生產(chǎn)任務要求，發(fā)動機缸體機械加工自動生產(chǎn)線由臥式加工中心CWK500和CWK500D加工中心、專用銑/鏜床、立式加工中心matec-30L等設備組成。（1）頂?shù)酌婕巴呱w止口面粗銑組合機床 本機床為雙面臥式專用銑床，采用移動工作臺帶動工件，機床采用進口西門子S7-200PLC系統(tǒng)控制，機床設獨立電控柜，切削過程自動化完成，有自動和調(diào)整兩種狀態(tài)；（2）高速臥式加工中心CWK500 該加工中心可實現(xiàn)最大流量的濕加工，但由于設備自動排屑處理系統(tǒng)是通過位于托盤下的內(nèi)置寬式排屑器而完成，該加工中心可以進行干加工；機床主軸轉速6000r/min，快速進給速度38m/min；（3）前后端面粗銑組合機床 機床采用液壓傳動；控制系統(tǒng)采用進口西門子S7-200PLC系統(tǒng)控制，機床具有一定的柔性；（4）采用機床TXK1500 本機床有立式加工中心改造而成形，具備立式加工中心的特點及性能，該機床具有高精度、高強度、高耐磨度、高穩(wěn)定性、高配置等優(yōu)點；（5）高速立式加工中心matec-30L 該加工中心主軸最高轉速9000 r/min?？刂葡到y(tǒng)采用西門子公司SINUMERIK840D控制系統(tǒng)（6）高速臥式加工中心CWK500D 主軸最高轉速15000 r/min。3. 發(fā)動機缸體機械加工工藝設計的主要內(nèi)容發(fā)動機缸體結構復雜，精度要求高，尺寸較大，是薄壁零件，有若干精度要求較高的平面和孔。發(fā)動機缸體機械加工的工藝特點是：主要是平面和孔的加工，加工平面一般采用刨、銑削等方法加工，加工孔主要采用鏜削，加工小孔多用鉆削。由于缸體結構復雜，因此如何保證各表面的相互位置精度是加工中的一個重要問題。3.1 毛坯的選擇發(fā)動機缸體采用的材料一般是灰鑄鐵HT150、HT200、HT250，也有采用鑄鋁或者鋼板的，此發(fā)動機缸體采用高強度合金鑄鐵。缸體在加工前進行時效處理，以消除鑄件內(nèi)應力和改善毛坯的力學性能。提高毛坯精度，減少加工余量，是提高自動生產(chǎn)線系統(tǒng)生產(chǎn)率及加工質(zhì)量的重要措施。由于國外箱體類零件毛坯質(zhì)量和精度較高，其生產(chǎn)線系統(tǒng)已實現(xiàn)了毛坯直接上線，既省去了毛坯檢查裝置，也節(jié)省了由于毛坯質(zhì)量問題而浪費的加工工時，提高了綜合效益。因此，精化毛坯是提高生產(chǎn)率最有潛力的出路。對于發(fā)動機缸體生產(chǎn)線，可在零件上線前粗銑六個面，去除大部分余量，便于零件直接上線。3.2機械加工工藝基準的選擇和加工選擇合理的加工工藝基準，直接關系到能否保證零件的加工質(zhì)量。一般來說，工藝基準可分為粗基準和精基準。（1）粗基準對于上線的毛坯，其粗基準的選擇尤為重要，如果粗基準選擇不合理，會使加工余量分布不均勻，加工面偏移，造成廢品。在缸體生產(chǎn)線中，我們采用側面作為粗基準；（2）粗基準對于發(fā)動機缸體這種箱體零件來說，一般采用“一面兩銷”為全線的統(tǒng)一基準。對于較長的自動自動生產(chǎn)線系統(tǒng)，由于定位銷孔在使用過程中的磨損造成定位不準確，因此，將定位銷孔分為2-3段使用。在缸體定位銷孔的加工中，我們采用了以側面、底面和主軸孔定位，在加工中心上加工。3.3 機械加工加工階段的劃分和工序的安排一個零件往往有許多表面需要加工，當然表面的加工精度是不同的。加工精度較高的表面，往往要經(jīng)過多次加工；而對于加工精度低的表面，只要經(jīng)過一兩次就行了。因此，擬定工藝順序時，要抓住“加工精度高的表面”這個矛盾，合理安排工序和合理劃分加工階段。安排工藝順序的原則是：先粗后精，先面后孔，先基準后其他。在發(fā)動機缸體的機械加工中同樣應遵循這一原則。（1）粗加工階段 在發(fā)動機缸體的機械加工過程中，安排粗加工工序，對毛坯全面進行粗加工，切去大部分余量，以保證生產(chǎn)效率；（2）半精加工階段 在發(fā)動機缸體的機械加工過程中，為了保證一些重要表面的加工精度，安排一些半精加工工序，將精度和表面粗造度要求中等的一些表面加工完成，而對要求高的表面進行半精加工，為以后的精加工做準備；（3）精加工階段 對精度和表面粗造度要求高的表面進行加工；（4）次要小表面的加工 如螺紋孔，可以在精加工主要表面后進行，一方面加工時對工件變形影響不大，同時廢品率也降低；另外，如果主要表面出廢品后，這些小表面就不必再加工了，從而避免浪費工時。但是，如果小表面的加工很容易碰傷主要表面時，就應該把小表面加工放在主要表面的精加工之前；（5）輔助工序也要妥善安排 如檢驗工序，在零件粗加工階段之后，關鍵工序加工前后，零件全部加工完畢后，都要適當安排。對加工階段進行劃分，具有以下好處：首先，可以在粗加工后采取措施消除工作內(nèi)應力，保證精度；其次，精加工放在最后面，不至于在運輸過程中損壞工件已加工表面；再次，先粗加工各面，可以及早發(fā)現(xiàn)毛坯缺陷并及時處理，不會浪費工時。不過對于一般小工件就不要分的很細。3.4 缸體的主要加工表面和輔助工序缸體主要加工表面和輔助工序有：（1）平面加工 目前，銑削是發(fā)動機缸體平面加工的主要手段，國內(nèi)銑削進給量一般為300-400mm/min，與國外銑削進給量2000-4000 mm/min相比，相差甚遠，有待于提高，因此，提高銑削進給量，縮短輔助時間，是提高生產(chǎn)效率的主要途徑，發(fā)動機缸體精加工一些平面時的銑削進給量達到2399mm/min，大大提高了效率；頂面的銑削是缸體加工中的一個關鍵工序，其平面度要求為0.02/145mm，表面粗造度為Ra1.6um。在缸體的加工中，采用側面和主軸軸承孔定位，頂面、底面和中間瓦蓋面同時加工，在加工中采用線外對刀裝置，能較好地滿足發(fā)動機缸體加工精度要求；（2）一般孔系的加工 一般孔系的加工仍采用傳統(tǒng)的鉆、擴、鏜、鉸、攻絲等工藝方法。課題在設計具體的工藝方案時，采用涂層刀具、內(nèi)冷卻刀具等先進刀具，采用大流量冷卻系統(tǒng)，大大提高了切削速度，提高了生產(chǎn)率；（3）深油孔加工 傳統(tǒng)的加