機械英文論文

1、某機床托架零件制造工藝及工裝設(shè)計摘要：車床后托架是機床的附件，該零件的尺寸較小，雖然結(jié)構(gòu)形狀不是很復(fù)雜，但側(cè)面的三杠孔和底面的加工精度要求較高，還有對頂面的四孔的加工精度有一定的要求。為保證零件的裝配質(zhì)量和壽命，必須保證其尺寸精度，幾何精度，相對位置精度以及表面處理質(zhì)量。該文主要分析機床托架的加工工藝及工裝設(shè)計的要點和工藝制造方案。關(guān)鍵詞：機床托架 制造工藝 工裝設(shè)計機床托架為箱體類零件，主要是平面加工和孔系的加工。雖然平面加工精度要求較高，但加工精度比較容易控制，但孔系加工需要控制孔系的尺寸精度和為位置精度，還需要處理好孔系和平面的關(guān)系。1 托架個表面的加工方案機場托架的加工不但要達到設(shè)計要

2、求，還應(yīng)具有良好的機械加工性，良好的加工工藝，不但確保了加工精度，而且能夠提高加工效率。除此之外，加工設(shè)備的經(jīng)濟性，選擇合理的機床設(shè)備。根據(jù)零件的表面技術(shù)要求，合理安排粗、精加工工序。根據(jù)材料的性質(zhì)合理的加工工具，如經(jīng)過淬火的材料，硬度較大，一般選用磨削或電加工的方式。如果是大批量生產(chǎn)，應(yīng)選用專用機床，單件小批量則選擇一般加工方法，提高本廠加工工藝水平。前期準備工序分別為粗車、半精車、淬火和粗磨，平面的加工依次為粗銑、精銑，孔的加工依次為粗鏜、精鏜，頂面四孔的加工依次為鉆、擴、鉸。2 定位基準的確定2.1粗基準的確定選擇精加工基準時，為保證加工面與不加工面的位置精度關(guān)系，應(yīng)選擇位置精度較高的表

3、面為粗基準，或重要的表面微基準；為保證該表面有足夠的加工余量，應(yīng)選擇加工余量最小的為粗基準；為保證零件能夠準定位，應(yīng)選擇平整、光潔的表面為粗基準，同時粗基準不能同時使用?？紤]以上因素，機床后托架應(yīng)選擇側(cè)面三孔為粗加工基準。2.2精基準的確定為避免定位基準與設(shè)計基準不重合而產(chǎn)生不重合誤差，應(yīng)盡可能選擇設(shè)計基準為精基準；為避免基準轉(zhuǎn)換帶來的位置誤差，應(yīng)盡可能的選擇統(tǒng)一的基準；加工兩個被加工面時，難以確定定位基準，可以互為基準提高加工精度；此外，為保證零件加工時的穩(wěn)固性，選擇尺寸較大的平面為精基準。通過以上分析，結(jié)合本零件的特點，選擇底面和頂面兩孔為精加工基準。3 工藝路線的制定3.1加工階段的劃分

4、首先加工統(tǒng)一的基準，先以孔定位粗、精加工頂平面，然后安排粗精加工工序。其加工階段分為粗加工、半精加工、精加工和光整加工四個加工階段。3.1.1零件的粗加工粗加工的目的是削去絕大部分金屬，為半精加工和精加工提供定位基準。但粗加工過程中，切削余量大，切削力加大，切削產(chǎn)生的熱量多，切削變形大，加工精度低。一半粗加工的公差等級為IT11-IT12，粗糙度為Ra80-100um。3.1.2半精加工半精加工是為主要面的精加工做好準備，為避免零件的變形，選擇合理的加工余量和切削速度。其公差等級為IT9-IT10，便面粗糙度為Ra10-1.25um。3.1.3精加工精加工階段用于切除剩余的材料，到達設(shè)計要求的

5、尺寸精度、位置精度和表面粗糙度，加工精度一般為IT6-IT17，表面粗糙度為Ra10-1.25um,為防止零件的劃傷，精加工安排的零件的加工的最后。3.1.4光整加工對于有較高表面質(zhì)量要求的零件，往往通過光整加工，改善其表面質(zhì)量。3.2加工路線的設(shè)計鑄造-清砂-熱處理（退火）-檢驗毛坯-銑底面-粗鏜空-粗銑油槽-半精鏜孔-精鏜空-鉆頂面四孔-锪孔-鉸孔-轉(zhuǎn)側(cè)面兩空-攻絲-去毛刺-檢驗-入庫4 專用夾具設(shè)計為提高加工精度，提高加工效率，降低工人的勞動強度，需要為機床后托架設(shè)計專用夾具，主要是為加工孔和銑底面設(shè)計夾具。4.1銑平面夾具的設(shè)計銑機床后托架的底面，應(yīng)滿足側(cè)面三孔的尺寸和平行度要求，同時

6、考慮零件的生產(chǎn)效率，使用V型塊作為自動找側(cè)面三孔的中心線夾具，由于該構(gòu)件體積小，易于切削，考慮選用手動加緊方式，并按照機床夾具設(shè)計手冊對其銑削力和夾具的加緊力經(jīng)行分析，分析加緊機構(gòu)的可靠性。當工作過程中出現(xiàn)磨損或零件尺寸放生變化時，應(yīng)根據(jù)設(shè)計情況使用支撐釘和V形塊進行調(diào)節(jié)。4.2鏜孔夾具的設(shè)計鏜孔主要是加工側(cè)面三孔，除了滿足軸線對平面的平行度要求外還應(yīng)滿足表滿粗糙度的要求，由于底面經(jīng)過粗銑，所以選擇底面為定位精基準，并以左側(cè)面和后側(cè)面為定位基準來設(shè)計鏜模，加緊機構(gòu)仍然選擇手動螺旋加緊機構(gòu)。為滿足加工工序的要求，還應(yīng)根據(jù)互換性與技術(shù)測量和機床夾具設(shè)計手冊分析夾具和定位方式是否滿足孔軸線與左側(cè)面的

7、尺寸公差及平行度公差。4.3頂面四孔夾具的設(shè)計由于頂面四孔沒有位置公差的要求，應(yīng)選擇左側(cè)面和后側(cè)面為定位基準來設(shè)計鉆模，加上底面共限制5個自由度，滿足定位要求。為保證該工序的公差小于工序的規(guī)定的公差，需要保證孔軸線與左側(cè)面的尺寸公差，即定位誤差、加緊安裝誤差、磨損造成的誤差以及刀具和夾具的相對誤差的總和小與規(guī)定誤差。5 結(jié)語機床托架的零件制造雖然工序不復(fù)雜，但工藝路線的制定和夾具的設(shè)計依然應(yīng)高度重視，只有合理科學的安排加工工序，不斷提高夾具的設(shè)計精度，才能提高零件的加工精度和生產(chǎn)效率，根據(jù)現(xiàn)有條件，設(shè)計適合本廠的加工工藝，提高機床托架零件的工藝制造水平。參考文獻【1】趙家齊.機械制造工藝學課程

8、設(shè)計指導(dǎo)書.2版北京：機械工業(yè)出版社,2000.【2】史全福.金屬切削手冊.3版.上海：上?？茖W技術(shù)出版社，2000.【3】陳家芬.實用金屬切削加工工藝手冊.2版.上海上?？茖W技術(shù)出版社,2005.A Machine Bracket Parts Manufacturing Process and Tooling DesignAbstract: the lathe after the bracket is machine tool attachment ,the size of the parts is small, although the shape of the structure is

9、not very complicated, but the side of The three lever hole and the bottom of the machining precision requirement is high, and the top surface of the machining accuracy of the four-hole has certain requirements. In order to ensure the quality and life of the assembly and parts of life, must ensure th

10、e dimensional accuracy and geometric accuracy, the relative position precision and surface processing quality. This paper mainly analyzes the key points of bracket machine processing technology and tooling design elements and process manufacturing solutions.Keywords: machine bracket manufacturing pr

11、ocess tooling designThe machine bracket for box-type parts, processing is mainly plane processing and holes. Although the plane process require high precision, the processing precision is easy to control, but the hole processing need to control the pore system of the dimensional accuracy and positio

12、nal accuracy, also need to deal with the relationship between hole and plane.The 1 bracket surface processing schemeAirport bracket processing not only to meet the design requirements, but also has good machinability, good process, not only ensures the precision, but also can improve the processing

13、efficiency. In addition, the economic efficiency of processing equipment, a reasonable choice of machine tools. According to the technical requirements of the part surface, reasonable arrangements for roughing and fine finishing process. According to the reasonable nature of the processing tools and

14、 materials, such as quenched materials, which is very hard, generally used in grinding or EDM approach. If mass-produced, should use special tools, single and small quantities? select general processing methods to improve the level of processing factory. Preparatory steps were roughing, semi-finishi

15、ng car, quenched and coarse grinding, plane processing were rough milling, precision milling, hole machining were rough boring, fine boring, the top surface of the processing order of the four-hole drilling, expanding , hinges.2. Determine the location datum2.1 Determination of crude benchmarkIn ord

16、er to ensure the accuracy relationship between the position of the machined surface and not machined surface, we should choose a higher position accuracy surface as reference or important surface as reference when selecting finishing benchmarks. To ensure that the surface has enough allowance, we sh

17、ould select the smallest allowance for crude benchmark; To ensure the parts to precise positioning, we should choose flat, smooth surface as rough benchmark, and benchmark crude cannot be used simultaneously. Considering the above factors, we should select the side three holes as rough machining dat

18、um for bracket machine after.2.2 Determination of fine benchmarkTo avoid locating datum does not coincide with the design basis and produce no coincidence error, we should choose the design basis for the fine as a reference; to avoid position errors caused by datum transformation we should set a sin

19、gle datum; when processing the two machined surfaces , it is difficult to determine the positioning reference, the reference can improve the machining accuracy of each other; In addition, to ensure stability during processing part, selecting a larger size for the fine reference plane. Through the ab

20、ove analysis, combined with the characteristics of the parts, select two holes to finish bottom and top surfaces benchmark.3 the set of process route3.1 division processing stagesFirst, to set a unified benchmark, first to locate the hole rough, finishing top of the plane, and then arrange rough fin

21、ishing operations. The processing stage is divided into roughing, semi-finishing, finishing and finishing four stages of processing.3.1.1 Parts roughing machiningThe aim is to cut away most of the rough metal, provide positioning reference for semi-finishing and finishing. But roughing process, cutt

22、ing a large margin, the cutting forces increase, the heat generated by cutting, large cutting deformation, low precision. Half roughing tolerance class IT11-IT12, roughness Ra80-100um3.1.2 Semi finishes machiningSemi finishing is ready for the main surface finishing, avoiding the deformation of part

23、s, choosing a reasonable allowance for machining and cutting speed. The tolerance levels for the IT9-IT10, the surface roughness of Ra10-1.25um.3.1.3 FinishingFinishing stage for the removal of the remaining material to reach the required dimensional accuracy of the design, location accuracy and sur

24、face roughness, machining accuracy is generally IT6-IT17, surface roughness Ra10-1.25um, to prevent scratching of parts, finishing arrangements for the final part of the .3.1.4 FinishingFor a higher surface quality requirements of the parts, often through finishing, improve surface quality.3.2 Desig

25、n of processing routesCasting - sand - heat treatment (annealing) - Inspection rough - milling underside - rough boring empty - roughing the tank - semi-fine boring - fine boring empty - the top surface of the four-hole drilling - countersinking - reaming - turn two empty side - tapping - demurring

26、- Inspection - Storage4 special fixture designsTo improve the precision, improve processing efficiency; reduce labor intensity, the need for special fixtures after the machine bracket design, mainly for holes and milling underside design fixtures.4.1 milling plane fixture designAfter milling the bot

27、tom surface of the bracket, the sides should meet three holes the size and parallel degree requirements, taking into account the productivity of parts, using the V-block as an automatic three-hole side of the centerline of the fixture to find, since the members are small and easy cutting , consider

28、using manual methods to intensify, and its milling force and clamp force intensified by the line analysis, reliability analysis in accordance with the agency to step up, fixture design Manual. When worn or release part size changes occur during operation should be used to support the nail and V-bloc

29、k design be adjusted according to the situation.Boring fixture design 4.2Is the main processing side hole boring, in addition to meet the requirements of the parallelism of the axis plane should also satisfy the table full of roughness requirements, because the bottom surface through the rough milli

30、ng, so the choice of the bottom surface is positioning precise basis, and to the left side and rear side as the positioning reference to design of boring die, clamping mechanism still choose manual spiral the clamping mechanism. In order to meet the requirements of machining process, also should be

31、based on the analysis of interchangeability and technical measurement and machine fixture design handbook clamps and locating way whether meet the dimensional tolerances of hole axis and the left side and parallelism tolerances.Design of 4.3 top four holes jigThe top surface of the four holes withou

32、t position tolerance requirements should choose the left side and rear side as the positioning reference to the design of drilling jig, coupled with the bottom surface of a total limit of 5 degrees of freedom, to meet the positioning requirements. In order to ensure that the specified tolerance of less than the processes of the process tolerances