零件的结构工艺性.ppt

ManufacturingProcessConsiderations零件的结构工艺性,Castingstructure铸件结构Commonmachiningstructures机加工常见结构Structureofdrillhole钻孔结构,请点击相应标题显示其内容,Castingstructure铸件结构,SandboxcoverOverflowPouringhead上砂箱冒口浇口,1.Draft起模斜度:,The120（3）draftalongthedrawingdirectionofthepatternfacilitatestotakeoutthepatternwhilemolding.铸件造型时，为便于取出木模，沿脱模方向的表面做出120（3）的起模斜度。,请点击鼠标左键显示后面内容,Ifthedraftisverysmall,itcanbeomitted,Ifnecessary,itcanbeincludedintechnical.起模斜度较小时,在图中一般不画出,必要时可注写在技术要求中。,Sandbox下砂箱,Model模型,Cavity型腔,Sand型砂,2.Filletsincastings铸造圆角:,Theremustbearadiuswheretwosurfacesmeet,inordertoavoidsanddropswhileremovingthemouldandshrinkagecavityandshrinkagecrackwhilecooling.在铸件表面相交处应有圆角,以免脱模时砂型落砂,同时防止铸件冷却时产生裂纹或缩孔。,Machinesymbol机加工符号,请点击鼠标左键显示后面内容,Castingstructure铸件结构,Theintersectionlineisneededinordertodistinguishthevarioussurfaces.Theonewehaveprovidediscalledrun-outline.Therepresentationofatransitionlineissimilartothatofintersectionline.Theonlydifferenceisthattheendoftherun-outlineisnotconnectedwiththecontourlineoftheradius,andthelinestyleisathinsolidline.为了区分不同形体的表面,仍要画出相贯线,这种相贯线称为过渡线。过渡线的画法和相贯线相同,只是其端点处不与圆角轮廓线接触,且线型为细实线。,3.Wallthickness铸件的壁厚:,Toavoidshrinkagecavityandshrinkagecrackcausedbydifferentcoolingspeeds.Duringthedesignphase,itisamusttomaintainuniformwallthicknessorasmooth.Onemustavoidunequaldesignssuchasthicknessabruptvaryingorlocalthickpartialareas.为防止浇铸零件时,由于壁厚不匀而冷却速度不同产生的缩孔和裂纹,在设计铸件时,应使壁厚尽量均匀或逐渐过渡,以避免壁厚突变或局部肥大的不匀现象。,请点击鼠标左键显示后面内容,Smoothtransition平滑过渡,Castingstructure铸件结构,Maintainuniformwallthickness壁厚均匀,1.Bossclubandrecessedsurface凸台与凹坑：,Usually,allsurfacesmountedonotherpartsneedtobemachined.Thebossorrecessedsurfaceisaddedtokeepgoodcontactbetweenthesurfacesoftwopartsandtoreducethemachiningareaandmanufacturingcost.零件上凡与其他零件接触的表面一般都要加工，为了保证两零件表面的良好接触，同时减少加工面积，以降低制造费用，在零件的需接触表面处常设计成凸台、凹坑的形式。,请点击鼠标左键显示后面内容,Commonmachiningstructures机加工常见结构,2.Chamferandround倒角与圆角:,Toeliminateburrsandflashesinordertopreventhumanhandsfromcuttingandtofacilitatemounting,theendsofboththeshaftandtheholeusuallyneedtobechamfered.为了去除零件的毛刺、锐边，以防止划伤人手和便于装配，在轴和孔的端部通常需加工出倒角。,Avoidcracks避免断裂,Thatis,thesharpedgeofshaftendiscutbyaconicalcuttingtoolwitha45degreeapexangle.即用一锥顶角为45的圆锥刀头切除其端部锐边。,请点击鼠标左键显示后面内容,Commonmachiningstructures机加工常见结构,Anarctransitionusuallyremainsattheshaftshoulder,whichiscalledround,inordertoavoidcrackscausedbypressureconcentration.在轴肩处，常常制成圆弧过渡，即圆角，以避免因应力集中而产生裂纹。,Commonmachiningstructures机加工常见结构,Undercut退刀槽,Undercut退刀槽,Grindingundercut砂轮越程槽,Grindingundercut砂轮越程槽,Grindingsurface精磨表面,Grindingsurface精磨表面,3.Escapeandgrindingundercut螺纹退刀槽和砂轮越程槽:,Anescape,grindingortravelinglimitundercutneedstobeproducedattheendofthesurfacetobemachined,inordertoeasilywithdrawthecutterorgrindingwheelwhiletappingorgrindingexternaldiameter.在车削螺纹或磨外圆时,为便于退刀或使用砂轮,需要在待加工面末端先切出退刀槽或砂轮越程槽。,请点击鼠标左键显示后面内容,Thedimensionoftheescapeisidentifiedaswidthdepthorwidthdiameter.退刀槽及越程槽的尺寸注成“宽度深度”或“宽度直径”。,Theaxisofthedrillshouldbeperpendiculartothesurfacetobedrilled,inordertoensurecorrectdrillingpositionandpreventthedrillfrombreakingcausedbyunequalimpactforce.用钻头钻孔时，为保证钻孔位置准确和避免钻头因受力不均而折断，应使钻头轴线垂直于被钻孔零件的表面。,请点击鼠标左键显示后面内容,Structureofdrillhole钻孔结构,Theintersectionpointwheretheholeandtheobliqueplanemeetisnecessarytosettoplatformandnotchstructure.Iftheanglebetweenthedrillandtheobliqueplaneislargerthan60,onecandrilltheholedirectly.在与孔轴线倾斜的表面处,常需设计出平台或凹坑结构,但当钻头与倾斜面的夹角大于60时,也可以直接钻孔。,本小节结束,谢谢您的认真学习！,退出,前一页,Castingstructure铸件结构,不与轮廓线接触,在图片上点击鼠标左键“暂停”或再次“播放”,Castingstructure铸件结构,在切点附近断开,在图片上点击鼠标左键“暂停”或再次“播放”,Castingstructure铸件结构,在图片上点击鼠标左键“暂停”或再次“播放”,Castingstructure铸件结构,在图片上点击鼠标左键“暂停”或再次“播放”,Commonmachiningstructures机加工常见结构,请点击鼠标左键显示后面内容,Grindingsurfacebygrindingwheel砂轮正在精磨工件的表面,Commonmachiningstructures机加工常见结构,Structureofdrillhole钻孔结构,Surfacestructureofthedrillhole钻孔的表面结构,Representationoftheholeanddimensionofadrill钻孔的尺寸标注,Grin