试验指导书五轴数控磨刀机原理及实践

1、实验指导书五轴数控磨刀机原理及实践要加工出合格的工件，必须根据工件的加工工艺要求，正确地设计和使用刀具，以保证达到工件所要求地尺寸、形状精度和表面质量。金属切削刀具的种类很多，对于标准刀具，需要根据刀具的工作原理和结构特点正确地选择和使用；对于非标准刀具则需要根据工件的加工要求进行专门的设计和制造。经过精心准备，制造工程基础教学组与德国saacke公司培训中心尝试进行校企合作开展学生实验课程的工作。本次实验的主要目的是结合生产实际，通过先进的制造设备及手段，使学生能够掌握刀具的设计原理，合理选择刀具设计参数，正确设计刀具结构，熟悉刀具从设计到制造的全过程。1 .实验目的1 .结合生产实际，给学

2、生介绍先进的生产理念，作为课堂内容的拓展和补充，加深对所学知识的理解；2 .锻炼实验设计能力和动手能力，熟悉刀具由设计到制造的全过程；3 .掌握有关磨削加工的知识，了解刀具磨床的结构及工作原理，；4 .掌握钻头设计、加工的全过程；2 .指导人员德国Saacke公司中国工程师、德国工程师(英语交流)、实验指导教师3 .实验内容由Saacke公司的指导人员负责讲解，并利用该公司所提供的五轴数控磨刀机及相应的CAD/CAM软件，参加实验的每组同学完成所选刀具的设计和制造。本实验主要包括以下内容：(1) 讲解Saacke五轴新概念刀具磨床的结构及工作原理。(2) 讲解钻头、铳刀等刀具设计、加工原理(3

3、) 讲解有关磨削加工的知识，包括砂轮、切削液等(4) 在刀具设计加工仿真软件上完成相应刀具的CAM设计(5) 在Saacke五轴刀具磨床上完成所设计刀具的加工4 .实验设备、仪器及工具1 .机床：uwn型五轴数控磨床2 .软件：NUMROTOplus3 .试件：45#钢棒料（细长棒料）4 .计算机5 .千分表、游标卡尺6 .刀具角度测量仪5 .准备工作1 .熟悉钻头、铳刀的结构特点、设计原理和制造方法;2 .熟悉本指导书附录中关于磨削的知识；3 .牢记操作注意事项及操作安全。6 .UWII型五轴数控磨床简介图1.uwn型五轴数控磨床UWH型五轴数控磨床，功率15KW,可以用于刀具的制造和修磨，

4、并可配置自动上下料装置，以满足大批量生产的需要。机床采用Windows操作系统，人机对话式窗口，界面友好，旁边有图形支持窗口，可对加工刀具进行三维立体显示和加工模拟，并且留有用户开发界面。在磨头上装有三维Renishaw测头，可以对刀具的长度、直径、螺旋角等参数进行自动测量，并自动输送到计算机中，方便可靠。该机床主要技术参数如下：技术特点：转塔式磨头，装有三根砂轮芯轴，可配9片砂轮一磨轴马达功率15KW一数字控制一磨轴转速2,000-8,000rpm一工件头直接驱动，转速600rpm(可选)自动上料系统(可选)每个托盘最多可装40把刀具工件参数：300mm250mm350mm一最大直径一全磨制

5、最大直径一全磨制最大切削刃长七.实验报告1 .实验目的2 .实验内容3 .实验步骤4 .实验结果(1) 利用刀具设计加工CAD/CAM软件系统NUMROTOplus完成相应刀具的CAM设计(2) 利用uwn型五轴数控刀具磨床和棒料加工出所设计的刀具(3) 给出设计加工的钻头的测量角度5 .实验分析与总结(1) 分析所设计钻头结构特点和刀具几何参数对加工的影响；(2) 分析五轴数控磨床的工作原理以及砂轮的特性由哪些因素决定；(3) 分析切削液的种类及切削液的使用情况对磨削加工的影响；(4) 对本次实验的感想与建议；8 .建议建议大家在实验前做好准备工作，在实验中每组同学可进行分工，以提高实验效率

6、9 .附录GrindingGeneralintroductionGrindingmeanscuttingwithgeometricallynotdefinededges.Therotatinggrindingbodiesarecomposedofboundabrasivegrainsandimbeddedpores,functioningas"chipchambers”儿Advantagesofgrinding* Highsurfacequalityofthegroundparts* Goodmachinabilityofhardanddifficulttomachinemateri

7、alsHightimegrindingvolume.Partially,similarvaluesasforplaningandturningarepossible.SurfacegrindingmachinesOnsurfacegrindingmachinesplanesurfacesaremachinedbytheperipheryorbythefaceofthegrindingwheel(figure).Therearedifferentkindsofmachines:oneexecutionwithhorizontalandverticalgrindingspindle,theothe

8、rwithlongandwithrotarytable.Longtablesaremeantforbiggerresp.longerworkingpieces.Roundorrotarytablesaresuitedforsmallerpieces.Smallerpiecesdonotneedthechangeofdirectionattheend.Thereforeacontinuousfeedmotionispossible.Ongrindingmachinesthetool(grindingwheel)iseffectingthecuttingmovement.Dependingonth

9、emachinetypeordesign,theplungeandthefeedmotionareeffectedeitherbytheworkingpieceorbythetool.SurfacecylindricalgrindingmachinesOnthesemachinestheworkingpieceismostlyclampedbetweenthecenters.Itgetsarotarymotion.Thecuttingmovementiseffectedbythegrindingwheel.Thegrindingwheelcanbefedfrombehindtotheworki

10、ngpiece.Longworkingpiecesrequirealongitudinalfeed(figure),whichismostlyeffectedbytheworkingpiece.Hereaslide(workingpieceslide)isrequired,whichcanbeadjustedtodifferentstrokelengths.Theworkingpiecetableisfixedontheslide.Machineswithahorizontalspindlearemostlyusedforperipherygrinding.Infigureyoucanseed

11、ifferentexamplesofuse.Verticalspindlesareoftenusedforfacegrinding.Onbothmachinetypestheslidesaremostlyhydraulicallyoperated.Hydraulicdrivesarevibrationfree,thefeedisinfinitelyvariable.Highqualityslideguidesandgoodlubricantconditionsontheguidesurfacesareveryimportantinordertoavoidthestick-slip-effect

12、.Alsoveryimportantaregoodspindlebearingassemblies.References/characteristicsofagrindingwheelOnfigure1(pagel)youcanseethebodyofagrindingwheel.Thefigureshowstheabrasivegrains,thebondingmaterialandthepores.Whenselectingthesuitablegrindingwheel,fivedecisionshavetobemade.1Abrasivematerial(chemicalcomposi

13、tionoftheabrasivegrain).Themostimportantabrasivematerialsare:corundumA,siliconcarbideC,boronnitrideBanddiamondD.Corundumsaremainlycomposedofaluminiumoxide(AI2O3).Youhavetodifferbetweenseveraldegreesofpurity.Normalcorundum:94.97H%AI2O3.specialfusedalumina:morethan99%AI203Coojndumsareforexamplesuitedf

14、orthegrindingoflongcuttingmaterials.Siliconcarbideisharder.Itissuitedforthegrindingofshortcuttingmaterialsasforexamplegrayiron,chillcasting,carbide.grabrrrtttri.|Mme30.702.Granulation(grainsize)8c36IGAInthestandarddesignationthegrainsizew12isspecifiedwithanumber,forex.80.141660170b0Itspecifiesthenum

15、berofmeshes(per20inch)241000ofafilterbywhichthegrainswere1200sortedout.3. Hardness(Resistanceofthegrainsagainstbreakingoutofthebonding).Aseverycuttingtooldoes-grainsaredullingafteracertaintime.Whenthewheelhardnessisselectedcorrectly,thedulledgrainbreaksoutduetothehigherloadingandallowstherefore,that

16、new,sharpgrainscanwork.Thematerialoftheworkingpiecehasabiginfluenceonthehardnessselection.Hereyouhavetoconsider:Hardmaterialsrequiresoftwheels,softmaterialsrequirehardwheels.Whenhardmaterialsaremachinedthegrainsaredulledearlierandhavetodisconnectearlierfromthebonding.Thehardness(oneletterforex."

17、;M')referstothestationarywheel.AecDwochEFG攵hrw«ichH1Jo<KWCKhLMNOmittrlPaRshenTuVwwhrhartXYZAu&ef&thartArtificialresin-Bondingscontactzone).Duringinternalgrindingthegrainischargedlessandreststhereforelongerinthebonding.Sothewheelseemsharder.Inthefollowingyoufindotherpossibilities,

18、howtoincreasetheactivehardness(precondition:theothermachiningdatastaythesame). settinganewgrindingwheel(duetothebiggerdiameter) increasingthecuttingspeed(chipsectiongetssmaller). reducingthecuttingdepth.Selection:Jotcommentforselection:Thecutterhasahardnessof61HRC.Hereyoushoulduseagrindingwheelsofte

19、rthanJot.Fortheselectionhowever,measureandformprecisionhavetobetakenintoconsideration.Softgrindingwheelswearoutfaster.Andsoitismorediffculttokeepthegivenformandmeasuretolerances.4. Structure(spaceportionofgrains,bondingmaterialandpores)1234567891011121314<一openstructure>Theporesarenecessaryasc

20、hipsections.Theirsizeandquantityhavealsoinfluenceonthehardness(seeabove).Awheelbeingtootightistoohardandhastoolowefficiency.Withawheelbeingtooopen,itmightbedifficultdogetacertainsurfacequality.Ascharacteristicforthestructureanumberisused.Selection:structure55. Bonding(material,whichbindsthegrains)Th

21、ebondingisalsoresponsibleforthehardnessandespeciallyfortheelasticityofthegrindingwheel.Thebondinghastoendureamechanicalandalsoaveryhighthermalloading.Inthefollowingtherearementioned2kindofbondinQCharacteristicsCeramicgoodhardnessgraduationpossibilities荻锭?Bondingsresistanceagainstwaterandoil也舞礁V*indi

22、fferencetohighheating,but您修浦击 sensitivitytoimpacts muchmoreelasticthanceramicbondings(especiallyimportantforthingrindingwheels) Bytheelasticattitudethegrainsareprotectedagainstoverload.Selection:V(CeramicBonding)Thestandarddesignationofthechosengrindingwheelis:Grindingwheel。用69120*250*2576庆60内5VChec

23、kanddressingofthegrindingwheels,rulesforpreventionofaccidentsDuringgrindingthedangerofaccidentsisveryhigh.Whenthegrindingwheelbreaks,thepartsflyingaroundmaycauseadeadlyaccident,iftheyarenotcaughtbyaprotectingdevice.Thefollowingrulesforpreventionofaccidentsarealsoincludingthefieldoffreeformgrinding,(

24、grindingofknifes,scissors,etc.) Beforedressingthegrindingwheelyouhavefirsttoeffectanacoustictest.Thewheelhastobekeptintheboreandisslightlyhitforex.withapieceofhardwood.Thesoundmustbehigh. Theflangesmusthavethecorrectsize(S>1/3Dwhenusingprotectivecaps.S=2/3Dwithoutprotectivecaps,S=112Dforconicalwh

25、eels.Theflangesmusthavethesamesize.Youmustputintermediatelayersoutofelasticmaterialbetweentheabrasivewheelsandthedampingflanges(forex.rubberorfelt).Thusirregularitiesonthegrindingwheelsurfaceshallbecompensated Thegrindingwheelmustbeeasytosliponthespindle.Whenyouhavesimplegrindingmachines,theworkrest

26、shavetobeputclosetothegrindingwheelandhavetobereadjustedregularly. Pleasepayattentiontothemaximumrotationfrequency.Onthegrindingwheelyoucanseethemaximumallowableperipheralspeed,forexonabluestripe(blue:vc<45m/s). Beforethefirststartpleasetakecarethatnotoolsorotherthingsmaybeacquiredbythegrindingwh

27、eel.eAftereachnewsettingyouhavetoeffectatestrunningofatleastfiveminuteswiththeratedmaximumrotatingfrequency. Duringgrindingyouhavetowearprotectivegoggles.BalancingDuringgrindingyouworkwithhighperipheralspeedsandthereforealsowithhighrotatingfrequencies.Whenusingunbalancedgrindingwheels,youhavetoexpec

28、tunbalanceandthecorrespondingcentrifugalforce.Unbalancedgrindingwheelscausevibrations,whichmayimpairthesurfacequalityandreducethelifeenduranceofthegrindingwheelandthemachine.I.SHUFlarth-HjITi/ZwischecMer.rSAACKEWorkshopGrindingThegrindingwheelshavetobebalancedtogetherwiththeirflanges.Inmanycasesstat

29、icbalancingwithcompensationmassesissufficient.Thegrindingwheelsatisfiesineachpositionthemasspoint.Iftherearehighdemandsresp.verylargewheels,youhavetobalancedynamically.CylindricalgrindingsurfacecylindricalgrindingThestud025mmofthebevelpinionhasalengthof20,3mm.Ifyouhaveagrindingwheelwidthof25mmitispo

30、ssibletofinishthediameterwithoneplunge-cutThisworkingmethodiscalledcrossgrinding.Duetotheshortproductioncycleitisveryeconomical.Aftergrindingthediameter,theendfacehastobemachined.Thisprocessiseffectedwiththefrontfaceofthegrindingwieel.Bybevelingitispossibletomachinebothsurfacesinthesametimewithonepl

31、unge-cut.Wfilegrindingiseffected.Withthismethodacertaincontouriscompletedbyoneplunge-cut.Forlongerpartsyouneedeitheralongitudinalfeed(swinggrinding)orseveralplunge-cutsareplacedsidebyside.Thefirstpossibilityyoufindmoreoften,forexbecausebythismethodyoucanreachacontinu

32、ouschipremoval,theproductiontimeisreduced.Fortheswinggrindingthegrindingwheelhastohavealittleoverrun(1/3to1/4ofthewheelwidth).Ifnot,attheendsitwillnotbepolishedenough.Forthebearingdiameter40mmofthedrivegearwheelthefollowingshiftisnecessary:L=L+1Z3*BL:shiftlengthI:pinlengthattheL=54mm+1/3*25mmworkpie

33、ce(54mm)L«63mmB:grindingwheel-width(25mm)Duringgrindingthegrindingwheelmaybeapproachedverysensitively,Uiescaledivisionvalueamountsmostlyto1pm.Forautomaticapproachamargin(byamechanicaldevice)ispossible.However,afterdeactivationofthefeedthewheelcontinuesgrinding"outsparking".Thatwayther

34、espectofthemeasuretolerancesisverydifficult.Ameasurecontrolterminatesthegrindingprocessassoonastherequiredmeasureisreached.Centerlesssurfacecylindricalgrinding.Thespecialtyofthismethodisthattheworkpieceisnotfixedinaclampingdevice,butliesfreeonahardrest.Aregulatingwheelsupportstheworkpiece,inthesamet

35、imethewheeltransfersitsperipheralspeedontheworkpieceandenablessothegrindingprocess.PlaneorsurfacegrindingForthegrindingofplanesurfacesthereexistparallelstomilling.Howevertheconsiderationsofthemillingcannotsimplybetransferred,becausethetoolhasanotherstructureandbecauseyouworkwithotherspeeds.Duringthe

36、facegrindingthereisabigcontactareabetweenthegrindingwheelandtheworkpiecesurface.Therearethefollowingdangers:Intenseheatgeneration(duetothebigcontactarea).Forhardenedpiecesthestarttemperaturecanbeexceededlocally.Thatmeans:softareasaregenerated.Onaclosedfrontfacethechipsandalsothebrokenoutgrainshavedi

37、fficultiestocomeout.Thewheelcanbeclosedfromthechips.Possiblecountermeasuresarethefollowing:2XnncmsATbMStur3TdUfirftw.twScZrfM'Eon21Wcrk/rjucn4/yHdKhondgg5SdzDiscontinuitiesinthegrindingwheels(forex.segmentalwheels).Insomecasesitispossibletoinclinethespindle.Herebyhoweverthereareformdeviationsatthewxkpiece.Themachiningofthediscontinuedsurfacesisfavorable.Herebythegrainsagainandagainhitfreespaces,wherethechipsarekickedoffandwhereisnofriction.Alsothesingleedgescanere-touch".Duringperipherygrindingthecontactareabetweengrindingwheelandworkpieceisre