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第第2章章 冲裁模结构与设计冲裁模结构与设计 Chapter Twoblanking diesstructure and design 1第2章 冲裁模结构与设计 Chapter Two1 使板料分离的冲压工艺称为冲裁。使板料分离的冲压工艺称为冲裁。The stamping technique to divide the sheet matal is called blanking.There are various kinds of it.such as,cut down,punch,pierce,trim,incise,dissect and so on.冲裁工艺的种类很多,常用的有切断、落料、冲孔、冲裁工艺的种类很多,常用的有切断、落料、冲孔、切边、切口、剖切等。切边、切口、剖切等。冲裁是冲压工艺的最基本工序之一。冲裁是冲压工艺的最基本工序之一。blanking is one basic procedure of stamping technique。在冲在冲压加工中应用极广。它既可以直接冲出成品零件,压加工中应用极广。它既可以直接冲出成品零件,也可以作为弯曲、拉深和挤压等其它工序的坯料,也可以作为弯曲、拉深和挤压等其它工序的坯料,还可以在已成形的工件上进行再加工(切边、切还可以在已成形的工件上进行再加工(切边、切口、冲孔等工序)。口、冲孔等工序)。2 使板料分离的冲压工艺称为冲裁。2本章要点本章要点:important points of this chapterl冲裁工艺。冲裁工艺。Blanking technique.l典型冲裁模结构。典型冲裁模结构。Typical blanking dies constructer l冲裁模主要零部件的结构分析与标准冲裁模主要零部件的结构分析与标准的选用。的选用。The constructer analysis and standards selection of blanking dies important componentsl冲裁模设计要点冲裁模设计要点the important points of blanking dies design3本章要点:important points of this本章难点:本章难点:difficulties of this chapterl冲裁工艺。冲裁工艺。Blanking technique.l冲裁模设计要点冲裁模设计要点the important points of blanking dies design4本章难点:difficulties of this chap2 21 1 冲裁工艺冲裁工艺 Blanking technique.211 冲裁基本知识冲裁基本知识the basic knowledge of Blanking 在冲裁工艺中,以落料、冲孔应用最多。在冲裁工艺中,以落料、冲孔应用最多。The most use of it is punching and piercing.从板料上冲下所需形状的工件(或毛坯)称为落料。从板料上冲下所需形状的工件(或毛坯)称为落料。Run into the required types workpiece from the sheet matal(or roughcast)is punching.在工件上冲出所需形状的孔(冲去的为废料)称为冲孔。在工件上冲出所需形状的孔(冲去的为废料)称为冲孔。Run into the required forms workpiece(the washed thing washed thing is scrap)is is scrap)is pierce 落料和冲孔的变形性质完全相同,但在进行模具工作部分设落料和冲孔的变形性质完全相同,但在进行模具工作部分设计时,要分开加以考虑。计时,要分开加以考虑。Punching and pierce have the same distortion feature,but when doing the model work design ,we should distinguish them to consider them.,we should distinguish them to consider them.521 冲裁工艺 Blanking techniqu211 冲裁基本知识冲裁基本知识 the basic knowledge of Blanking6211 冲裁基本知识 the basic know211 冲裁基本知识冲裁基本知识the basic knowledge of Blanking 根根据据冲冲裁裁变变形形机机理理的的不不同同,冲冲裁裁工工艺艺可可以以分分为为普普通通冲冲裁裁和和精精密密冲冲裁裁两两大大类类。According to the different distortion mechanism,blanking technique has two types are common blanking and exact blanking.普通冲裁普通冲裁:common blanking 是是由由凸凸、凹凹模模刃刃口口之之间间产产生生剪剪裂裂缝缝的的形形式式实实现现板板料料分分离离。To make the edge of the male die and female die produce the shearing cranny to separate the sheet matal.精密冲裁精密冲裁:exact blanking 是是以以变变形形的的形形式式实实现现板板料料的的分分离离 。Through the distortion form to finish the sheet matal.前前者者冲冲出出的的工工件件断断面面比比较较粗粗糙糙,精精度度较较低低。后后者者冲冲出出的的工工件件不不但但断断面面比比较较光光洁洁而而且且精精度度也也较较高高,但但需需要要有有专专门门的的精精冲冲设设备备及及精精冲冲模模具具。The formers workpieces shearing surface is more rough,and the latter is more glabrous and the precision is higher,but it needs special precise equipment and model.7211 冲裁基本知识the basic knowl212 冲裁过程分析冲裁过程分析 the procedure analysis of blanking凸凸模模1与与凹凹模模2具具有有与与工工件件 轮轮 廓廓 一一 样样 的的 刃刃 口口。Male die 1 and female die 2 have the same edge with work profile.凸凸、凹凹模模之之间间存存在在一一定定的的间间隙隙。Male die and female die must existence gap.当当压压力力机机滑滑块块把把凸凸模模推推下下时时,便便将将放放在在凸凸、凹凹模模中中间间的的板板料料冲冲裁裁成成所所需需的工件。的工件。8212 冲裁过程分析 the procedure an212 冲裁过程分析冲裁过程分析the procedure analysis of blanking 当当模模具具间间隙隙正正常常时时,金金属属板板料料的的冲冲裁裁变变形形过过程程大大致致可可分分为为三三个个变变形形阶阶段段.When the mould gap is normal,the metal sheet matals blanking distortion procedure has 3 phases.(1)弹性变形阶段)弹性变形阶段 elastic distortion phase(2)塑性变形阶段)塑性变形阶段 plastic distortion phase(3)剪裂阶段)剪裂阶段 shearing crack phase 如下图如下图:9212 冲裁过程分析the procedure ana1010(1)弹性变形阶段)弹性变形阶段elastic distortion phase 当当凸凸模模开开始始接接触触板板料料并并下下压压时时,凸凸模模与与凹凹模模刃刃口口周周围围的的板板料料产产生生应应力力集集中中现现象象,使使材材料料产产生生弹弹性性压压缩缩、弯弯曲曲、拉拉伸伸等等复复杂杂的的变变形形。When the male die starts to touch with sheet matal and press it lowly,the sheet matal which around the male die and female dies edge produce the stress central phenomena,make the material produce the elastic compression,bend,extend and so on these complex distortion.板板料料略略有有挤挤入入凹凹模模洞洞口口的的现现象象。此此时时,凸凸模模下下的的材材料料略略有有弯弯曲曲,凹凹模模上上的的材材料料则则向向上上翘翘。间间隙隙愈愈大大,弯弯曲曲和和上上翘翘愈愈严严重重。随随着着凸凸模模继继续续压压入,直到材料内的应力达到弹性极限。入,直到材料内的应力达到弹性极限。11(1)弹性变形阶段elastic distortion ph(2)塑性变形阶段)塑性变形阶段 plastic distortion phase当凸模继续压入,板料内的应力达到屈服点,当凸模继续压入,板料内的应力达到屈服点,板料与凸模和凹模的接触处产生塑性剪切变板料与凸模和凹模的接触处产生塑性剪切变形。形。When the male die is gone on When the male die is gone on pressfitting,the stress in the sheet pressfitting,the stress in the sheet metal will get to the yield point,and metal will get to the yield point,and the tangency place of sheet metal and the tangency place of sheet metal and male die with cavity plate will have male die with cavity plate will have plastic sheer deformation.plastic sheer deformation.随随着着凸凸模模的的下下压压,应应力力不不断断加加大大,直直到到分分离离变变形形区区的的应应力力达达到到抗抗剪剪强强度度,塑塑性性变变形形阶阶段段结结束束。Withthemalediebeingpresseddown,the stress goes on aggrandizing.The plasticsheerdeformationplacewontbefinishedwithseparate deformed zone of stress gets to theshearingstrength.12(2)塑性变形阶段 plastic distortion(3)剪裂阶段)剪裂阶段shearing crack phase当当板板料料的的应应力力达达到到抗抗剪剪强强度度后后,凸凸模模再再向向下下压压,则则在在板板料料与与凸凸模模和和凹凹模模的的刃刃口口接接触触处处分分别别产产生生裂裂纹纹。After sheet matal stress gets to the shearing intension,the male die is gone on being pressed down and the fissure will be begot at the tangency place of sheet metal and male dies with cavity plates blade mouth apart.随随着着凸凸模模下下压压,裂裂纹纹逐逐渐渐扩扩大大并并向向材材料料内内延延伸伸。With the male die being pressed down,fissure is come to enlarge and extended to the inside of materials.当当上上、下下裂裂纹纹重重合合时时,板板料料便便被被分分离离。When surfissrue and lay-fissure coinage,sheet matal will be asundered.凸凸模模再再下下压压,将将已已分分离离的的材材料料克克服服摩摩擦擦阻阻力力从从板板料料中中推推出出,完完成成冲冲裁裁过过程程。And with male die being frictional ressistance and will be pushed out of the sheet matal and then the blanking course will be finished.13(3)剪裂阶段shearing crack phase当板料212 冲裁过程分析冲裁过程分析the procedure analysis of blanking在在正正常常的的冲冲裁裁工工作作条条件件下下,由由凸凸模模刃刃口口出出发发的的剪剪裂裂缝缝与与由由凹凹模模刃刃口口出出发发的的剪剪裂裂缝缝是是重重合合的的。这这时时可可以以得得到到如如图图2.4所所示示的的冲冲裁裁件件断断面面,它它具具有有明明显显的的四四个个特特征征区区。At At the the normal normal conditions conditions of of blanking blanking work,work,the the shear shear fracture fracture slots slots are are coinage,coinage,which which start start off off the the male male die die and and cavity cavity plate plate blade blade mouth.Now,mouth.Now,the the blanking blanking pieces pieces sever sever panel panel is is being being obtainde.Look obtainde.Look at at the the picture picture 2-4.It 2-4.It has has four evident earmark zones.four evident earmark zones.(1 1)圆角带)圆角带;circle angle zone(2)光亮带光亮带;euphotic zone(3)断裂带断裂带;fracture zone(4)毛刺。毛刺。burrburr14212 冲裁过程分析the procedure ana1515212 冲裁过程分析冲裁过程分析 the procedure analysis of blanking圆圆角角带带1又又称称塌塌角角 circle angle zone 1,has an alternate name fallen angle.材材料料塑塑性性愈愈好好,凸凸、凹凹模模之之间间间间隙隙愈愈大大,形形成成的的塌塌角角也也就就愈愈大大。The plastic of material is better,and the gap between male die and cavity plate is bigger,the fallen down angle will be bigger.光亮带光亮带2 2 euphotic zone 2 光光亮亮带带垂垂直直于于底底面面。材材料料塑塑性性愈愈好好,凸凸模模和和凹凹模模之之间间的的间间隙隙(图图中中Z Z2 2为为单单边边间间隙隙)愈愈小小,光光亮亮带带的的高高度度愈愈高高。The euphotic zone and the botton side are uprightness.The material plastic is better,the gap(the gap in z/2 is a single side one)between male die and cavity plate is smaller,and the hight of euphotic zone will be higher.16212 冲裁过程分析 the procedure an212 冲裁过程分析冲裁过程分析the procedure analysis of blanking断裂带断裂带3 3 fractured zone 3 断断裂裂带带表表面面粗粗糙糙,并并带带有有斜斜度度。凸凸模模和和凹凹模模的的间间隙隙愈愈大大,则则断断裂裂带带高高度度愈愈大大且且斜斜度度也也增增大大。Fractured zone has a crudity surface with a pitch.The gap between male die and cavity plate is bigger,the height of fractured zone will be higher and the pitch will be bigger.毛刺毛刺4 4 burr 4burr 4 紧紧挨挨着着剪剪裂裂带带的的边边缘缘,是是由由于于裂裂纹纹的的产产生生不不是是正正对对着着凸凸模模和和凹凹模模的的刃刃口口而而是是在在靠靠近近刃刃口口的的侧侧面面。That That next next to to the the edge edge of of shear shear fracture fracture zone,zone,is is causef causef by by fissure fissure generation,which generation,which is is closed closed up up the the flank flank of of blade blade mouth mouth but but not not against against the the male dies and cavitys blade mouth.male dies and cavitys blade mouth.17212 冲裁过程分析the procedure ana计算凸模和凹模尺寸的依据:计算凸模和凹模尺寸的依据:the gist of calculation male die and female dies size对对于于冲冲孔孔件件的的孔孔,决决定定与与轴轴类类零零件件配配合合性性质质的的是是它它的的最最小小尺尺寸寸,即即其其光光亮亮柱柱体体部部分分尺尺寸寸;对对于于落落料料件件,决决定定与与孔孔类类零零件件配配合合性性质质的的是是它它的的最最大大尺尺寸寸,也也是是它它的的光光亮亮柱柱体体部部分分尺尺寸寸。As As for for the the hole hole of of the the rush rush vent vent piece,piece,its its least least size size depends depends on on the the coordination coordination cy cy of of the the axle axle genus genus details,details,that that is is the the dimension dimension of of lustre lustre pole pole part;part;As As for for blanking blanking piece,its piece,its macrosize macrosize depends depends on on the the coordination coordination cy cy of of vent vent genus genus details,details,that that is is the the dimension of lustre pole,too.dimension of lustre pole,too.于是,可以得出如下重要的关系式于是,可以得出如下重要的关系式:落落料料尺尺寸寸 =凹凹模模尺尺寸寸 punching punching size=female size=female die die sizesize 冲孔尺寸冲孔尺寸=凸模尺寸凸模尺寸 pierce size=male die size pierce size=male die size 18计算凸模和凹模尺寸的依据:the gist of calcu213 冲裁件的质量分析冲裁件的质量分析 blanking pieces quality analysis1 1尺寸精度;尺寸精度;size precision2 2断面质量;断面质量;breaking surfaces quality3毛刺毛刺。burrburr19213 冲裁件的质量分析 blanking pie1尺寸精度尺寸精度size precision 冲冲裁裁件件的的尺尺寸寸精精度度与与许许多多因因素素有有关关,如如冲冲模模的的制制造造精精度度、材材料料性性质质、冲冲裁裁间间隙隙和和冲冲裁裁件件的的形形状状等等。The size precision of blanking piece is in relation to lots of factors,for example:(1 1)冲冲模模的的制制造造精精度度;dies constructive precision(2 2)材料性质;)材料性质;material quality(3 3)冲裁间隙;)冲裁间隙;blanking gap(4 4)冲裁件的形状。)冲裁件的形状。blanking pieces shape201尺寸精度size precision 冲裁件的尺(1 1)冲模的制造精度)冲模的制造精度 dies constructive precision 冲冲模模的的制制造造精精度度对对冲冲裁裁件件的的尺尺寸寸精精度度有有直直接接影影响响。冲冲模模的的精精度度愈愈高高,冲冲裁裁件件的的精精度度亦亦愈愈高高。The dies constructive precision has effect on blanking pieces size precision directly.21(1)冲模的制造精度 dies constructive(2 2)材料性质)材料性质material quality 对对于于比比较较软软的的材材料料,弹弹性性变变形形量量较较小小,冲冲裁裁后后的的回回弹弹值值也也少少,因因而而零零件件精精度度较较高高。而而硬硬的的材材料料,情情况况正正好好与与此此相相反反。To the softer material,elastic distortion quantity is smaller,and the re-flip value is small,so the component precision is higher.22(2)材料性质material quality (3 3)冲裁间隙)冲裁间隙blanking gap 如如间间隙隙过过大大,对对于于落落料料件件,其其尺尺寸寸将将会会小小于于凹凹模模尺尺寸寸,对对于于冲冲孔孔件件,其其尺尺寸寸将将会会大大于于凸凸模模尺尺寸寸。If the gap is too bigger as for fallen material piece,its side will be smaller than cavity size;as for rush vent piece,its side will greater than male dies.如如间间隙隙过过小小,对对于于落落料料件件,其其尺尺寸寸将将会会大大于于凹凹模模尺尺寸寸,对对于于冲冲孔孔件件,其其尺尺寸寸将将会会小小于于凸凸模模尺尺寸寸。If the gap is too smaller,as for fallen material piec,its side will be greater than cavity size;as for rush vent piece,its side will smaller than male dies.23(3)冲裁间隙blanking gap 如间隙过(4 4)冲裁件的形状)冲裁件的形状blanking pieces shape冲冲裁裁件件的的形形状状越越简简单单其其精精度度越越高高。The easier the shape is,the higher the precision is.24(4)冲裁件的形状blanking pieces shap2 2断面质量断面质量breaking surface quality 对对于于断断面面质质量量,起起决决定定作作用用的的是是冲冲裁裁间间隙隙。To it,its up to the blanking gap.To it,its up to the blanking gap.在在具具有有合合理理间间隙隙的的冲冲裁裁条条件件下下裂裂纹纹重重合合。Under Under the the condition condition of of the the proper proper gaps gaps blanking blanking,the the crack crack will will be be superposition.superposition.所所得得冲冲裁裁件件断断面面有有一一个个微微小小的的塌塌角角(the the angle angle of of dentdent),并并有有正正常常的的既既光光亮亮又又与与板板平平面面垂垂直直的的光光亮亮带带(euphotic zone),其其断断裂裂带带虽虽然然粗粗糙糙但但比比较较平平坦坦,虽虽有有斜斜度度但但并并不不大大,所产生的毛刺也是不明显的。所产生的毛刺也是不明显的。252断面质量breaking surface quality 2 2断面质量断面质量breaking surface quality26 2断面质量breaking surface qualit 2 2断面质量断面质量breaking surface quality 当间隙过大或过小时,就会使上、下裂纹不能重当间隙过大或过小时,就会使上、下裂纹不能重合。合。When the gap is too big or small,it will stop the upper and lower crack from superposition.(1 1)间隙过大:)间隙过大:the gap is too big 凸模产生的裂纹相对于凹模产生的裂纹向里移动一个凸模产生的裂纹相对于凹模产生的裂纹向里移动一个距离。距离。the male dies gap opposite female dies gap move one distance outward.板料受拉伸、弯曲的作用加大,使剪切断面塌角加大,板料受拉伸、弯曲的作用加大,使剪切断面塌角加大,光亮带的高度缩短,断裂带的高度增加,锥度也加大,光亮带的高度缩短,断裂带的高度增加,锥度也加大,有明显的拉断毛刺,冲裁件平面可能产生穹弯现象。有明显的拉断毛刺,冲裁件平面可能产生穹弯现象。27 2断面质量breaking surface qualit 2 2断面质量断面质量breaking surface quality(2 2)间隙过小:)间隙过小:the gap is too small the gap is too small 会使凸模产生的裂纹向外移动一个距离。会使凸模产生的裂纹向外移动一个距离。It will make the male dies gap move one It will make the male dies gap move one distance.distance.上、下裂纹不重合,产生第二次剪切,上、下裂纹不重合,产生第二次剪切,由凸模和凹模刃口所产生的裂从而在剪切面上由凸模和凹模刃口所产生的裂从而在剪切面上形成了略带倒锥的第二个光亮带。在第二个光形成了略带倒锥的第二个光亮带。在第二个光亮带下面存在着潜伏的裂纹。由于间隙过小,亮带下面存在着潜伏的裂纹。由于间隙过小,板料与模具的挤压作用加大,在最后被分离时,板料与模具的挤压作用加大,在最后被分离时,冲裁件上有较尖锐的挤出毛刺。冲裁件上有较尖锐的挤出毛刺。28 2断面质量breaking surface qualit3毛刺毛刺burrburr 冲裁过程的分析可知,冲裁件产生微小的毛刺是不可避冲裁过程的分析可知,冲裁件产生微小的毛刺是不可避免的。免的。According to the blanking procedure,it cant According to the blanking procedure,it cant avoid the blanking piece produce burr.avoid the blanking piece produce burr.若产品要求不允若产品要求不允许存在微小毛刺,则在冲裁后应增加去除毛刺的辅助工序。许存在微小毛刺,则在冲裁后应增加去除毛刺的辅助工序。正常冲裁中允许的毛刺高度见表正常冲裁中允许的毛刺高度见表2.2。If the products requirement is not allowed to exist the small burr,so we should add the assistant working procedure to remove the burr.The height of burr of the usual blanking is in the table 2.2.293毛刺burr 冲裁过程的分析可知,冲裁件产生微小的毛3毛刺毛刺burrburr若冲裁过程不正常,毛刺就会明显增大,这是不允若冲裁过程不正常,毛刺就会明显增大,这是不允许的。产生毛刺的原因主要有两个,其一是冲裁间许的。产生毛刺的原因主要有两个,其一是冲裁间隙不合理。隙不合理。If the procedure is not normal,If the procedure is not normal,the burr will become bigger,its not the burr will become bigger,its not permitted.There are 2 reasons of causing permitted.There are 2 reasons of causing burr,one of it is the improper blanking gap.burr,one of it is the improper blanking gap.(1 1)间隙过大,会产生明显的拉断毛刺。)间隙过大,会产生明显的拉断毛刺。(2 2)间隙过小,会产生尖锐的挤出毛刺。)间隙过小,会产生尖锐的挤出毛刺。(1)(1)The gap is too big that will snap the The gap is too big that will snap the burr obviously;burr obviously;(2)its too small that will pile out the(2)its too small that will pile out the burr stridentlyburr stridently.303毛刺burr若冲裁过程不正常,毛刺就会明显增大,这是不允3毛刺毛刺burrburr产生毛刺的原因其二是凸模或凹模磨钝后,其刃口产生毛刺的原因其二是凸模或凹模磨钝后,其刃口处形成圆角,这是产生毛刺的主要原因。处形成圆角,这是产生毛刺的主要原因。The The second reason is that produce the circle second reason is that produce the circle angle at the edge after abraded the male die angle at the edge after abraded the male die and the female die.And this is the main and the female die.And this is the main reason.reason.当凸模和凹模刃口带有圆角后,冲裁时材料中就减当凸模和凹模刃口带有圆角后,冲裁时材料中就减少了应力集中现象而增大了变形区域,产生的裂纹少了应力集中现象而增大了变形区域,产生的裂纹偏离刃口,凸模和凹模间金属在剪切断裂前有很大偏离刃口,凸模和凹模间金属在剪切断裂前有很大的拉伸,这就使冲裁断面上产生了明显的毛刺。的拉伸,这就使冲裁断面上产生了明显的毛刺。313毛刺burr产生毛刺的原因其二是凸模或凹模磨钝后,其刃口213 冲裁件的质量分析冲裁件的质量分析blanking pieces quality analysis 综上所述用普通冲裁方法所能得到的冲裁件,综上所述用普通冲裁方法所能得到的冲裁件,其尺寸精度与断面质量都不太高。金属冲裁件所能其尺寸精度与断面质量都不太高。金属冲裁件所能达到的经济精度为达到的经济精度为ITl4 ITl0级,要求高的可达到级,要求高的可达到ITl0 IT8级。厚料比薄料更差。若要进一步提高冲级。厚料比薄料更差。若要进一步提高冲裁件的质量,则要在冲裁后加整修工序或采用精密裁件的质量,则要在冲裁后加整修工序或采用精密冲裁法。冲裁法。To sum up the above arguments,use common blanking method gained blanking ware,its size precision and cut surface quality are all not very.Metal blanking wares economy accuracy are certainly attainable IT14-IT10.32213 冲裁件的质量分析blanking piec214 冲裁间隙冲裁间隙blanking gapblanking gap冲冲裁裁间间隙隙是是指指冲冲裁裁凸凸模模和和凹凹模模之之间间工工作作部部分分的的尺尺寸寸之之差差。如如图图2.6所所示示,即即 blanking blanking gap gap is is the the difference difference size size between between the the male male die die and and female female dies dies work work part.part.Look Look at at the the picture2.6.picture2.6.Z D凹凹 一一D凸凸如无特殊说明,冲裁间隙一般是指如无特殊说明,冲裁间隙一般是指双边间隙。双边间隙。If it has not other If it has not other special illustration,blanking special illustration,blanking gap is the bilateral gap.gap is the bilateral gap.33214 冲裁间隙blanking gap冲裁间隙是214 冲裁间隙冲裁间隙blanking gapblanking gap冲冲裁裁间间隙隙对对冲冲裁裁过过程程有有着着很很大大的的影影响响。甚甚至至可可以以说说间间隙隙对对冲冲裁裁件件的的质质量量起起着着决决定定性性的的作作用用。blanking blanking gap gap has has great great effect effect on on the the blanking blanking procedure.procedure.And And we we can can say say that that the the gap gap has has the the decisive decisive effect effect on on the the blanking pieces quality.blanking pieces quality.除除此此以以外外,间间隙隙对对模模具具寿寿命命也也有有较较大大的的影影响响。如如图图2.7所所示示是是冲冲裁裁时时作作用用于于模模具具刃刃口口部部分分的的力力。Besides Besides that,that,gap gap also also has has great great effect effect on on the the dies dies usage.usage.As As the the picture 2.7 has given us.picture 2.7 has given us.34214 冲裁间隙blanking gap冲裁间隙对214 冲裁间隙冲裁间隙 blanking gapblanking gap(1 1)间隙小时:)间隙小时:the gap is small.the gap is small.冲冲裁裁过过程程的的挤挤压压作作用用加加剧剧,冲冲裁裁力力F与与摩摩擦擦力力F增增大大,使使刃刃口口所所受受压压应应力力增增大大,造造成成刃刃口口变变形形与与端端面面磨磨损损加加剧剧,严严重重时时甚甚至至崩崩刃刃。加加之之过过小小间间隙隙的的二二次次剪剪切切所所产产生生的的金金属属碎碎屑屑因因摩摩擦擦发发热热粘粘附附在在凸凸模模和和凹凹模模上上又又加加剧剧了了刃刃口口的的磨磨损损。所所以以,过过小小间间隙隙会会使使模模具具寿寿命命降降低低。此此外外,小小间间隙隙还还使使模模具具制制造造的的难难度度增增加加。Undersize clearance can lead dies life down.And small clearance can lead difficulty of dies manufacture up.35214 冲裁间隙 blanking gap(1)间214 冲裁间隙冲裁间隙blanking gapblanking gap由由冲冲裁裁变变形形过过程程的的分分析析可可知知,决决定定合合理理间间隙隙值值的的理理论论依依据据是是应应保保证证在在塑塑性性剪剪切切变变形形结结束束后后,由由凸凸模模和和凹凹模模刃刃口口处处所所产产生生的的上上、下下剪剪切切裂裂纹纹重重合合。如如图图2.8所所示示。According According to to the the blanking blanking distortiondistortion procedure,the theory that decide the proper gap is to make sure the edge of the male die and female dies gap can be superposition.As the picture 2.8.36214 冲裁间隙blanking gap由冲裁变形214 冲裁间隙冲裁间隙 blanking gapblanking gap由由 图图 上上 的的 几几 何何 关关 系系 可可 得得:according to the relationship of the pictures geometry.Z=2(t b)tan=2t(1 b/t)tan式中式中 t 板料厚度板料厚度(material thickness);b/t 产产生生裂裂纹纹时时,凸凸模模压压入入板板料料的的相相对对深深度度(即光亮带的相对宽度);(即光亮带的相对宽度);最大切应力方向与垂线间的夹角。最大切应力方向与垂线间的夹角。软软钢钢(soft steel)=5 o 6 o;中中硬硬钢钢(mid-hard steel)=4 o5 o;硬钢硬钢(hard steel)hard steel)=4 o。37214 冲裁间隙 blanking gap由图上的214 冲裁间隙冲裁间隙 blanking gapblanking gap 由由上上式式可可以以看看出出,合合理理间间隙隙值值取取决决于于t、bt、等等三三个个因因素素。由由于于值值的的变变化化不不大大,所所以以,影影响响合合理理间间隙隙值值的的大大小小主主要要取取决决于于前前二二个个因因素素,即即影影响响间间隙隙值值的的主主要要因因素素是是板板料料厚厚度度和和材材料料性性质质。Because the value has not the great change,so the former 2 factors influence the proper gap values size,in other words,the main factor to influence the gap value are the thickness of the sheet matal and the quality of the material.板板料料厚厚度度增增大大,间间隙隙数数值值应应正正比比地地增增大大。反反之之板板料料 愈愈 薄薄 则则 间间 隙隙 愈愈 小小。sheet matals thickness becomebigger,and the gap value also will be bigger with it.On the contrary,it has the opposite feature.38214 冲裁间隙 blanking gap 214 冲裁间隙冲裁间隙 blanking gapblanking gap 材材料料塑塑性性好好,光光亮亮带带所所占占的的相相对对宽宽度度bt大大,间间隙隙数数值值就就小小。而而塑塑性性差差的的硬硬材材料料,间间隙隙数数值值就就大大一一些些。另另外外,bt还还与与板板料料的的厚厚度度有有关关。对对同同一一种种材材料料来来说说,薄薄料料冲冲裁裁的的bt 比比厚厚料料冲冲裁裁的的bt大大,因此,薄料冲裁的间隙值更要小一些。因此,薄料冲裁的间隙值更要小一些。概概括括地地说说,板板料料愈愈厚厚,塑塑性性愈愈差差,则则间间隙隙愈愈大大;材材料料愈愈薄薄,塑塑性性愈愈好好,则则间间隙隙愈愈小小。In total,the thicker the sheet matal is,the worse the plastic ability is,and the bigger the gap is;then it it has the opposite feature.39214 冲裁间隙 blanking gap 214 冲裁间隙冲裁间隙 blanking gapblanking gap在在实实际际生生产产中中,合合理理间间隙隙的的数数值值是是由由实实验验方方法法所所制制定定的的表表格格来来确确定定的的。In In fact,fact,proper proper gaps gaps numerical numerical value value is is decided decided by by the tables of the experiments method.the tables of the experiments method.由由于于冲冲裁裁间间隙隙对对断断面面质质量量、工工件件的的尺尺寸寸精精度度、模模具具寿寿命命、冲冲裁裁力力等等的的影影响响规规律律并并非非一一致致,所所以以,并并不不存存在在一一个个绝绝对对的的合合理理间间隙隙数数值值,能能同同时时满满足足断断面面质质量量最最佳佳、尺尺寸寸精精度度最最高高、模具寿命最长、冲裁力最小等各方面的要求。模具寿命最长、冲裁力最小等各方面的要求。40214 冲裁间隙 blanking gap在实际生214 冲裁间隙冲裁间隙 blanking gapblanking gap 在在确确定定间间隙隙值值大大小小的的具具体体数数值值时时,应应结结合合冲冲裁裁件件的的具具体体要要求求和和实实际际的的生生产产条条件件来来考考虑虑。其其总总的的原原则则应应该该是是在在保保证证满满足足冲冲裁裁件件剪剪切切断断面面质质量量和和尺尺寸寸精精度度的的前前提提下下,使使模模具具寿寿命命最最长长。When When make make sure sure the the gaps gaps material material numerical numerical value,value,we we should should consider consider it it according according to to the the blanking blanking pieces pieces requirement requirement and and its its practical practical produce produce condition.The condition.The main main principle principle should should be be to to meet meet the the blanking blanking pieces pieces surfaces surfaces shearing shearing quality quality and and the the size size precision,precision,and and make make the the dies dies usage usage longest.longest.表表2.3列出了汽车拖拉机行业常用的较大初始间隙表;列出了汽车拖拉机行业常用的较大初始间隙表;表表2.4列出了电器仪表行业所用的较小初始间隙表。列出了电器仪表行业所用的较小初始间隙表。41214 冲裁间隙 blanking gap 在确214 冲裁间隙冲裁间隙 blanking gapblanking gap 从从表表格格中中可可以以看看出出,合合理理间间隙隙值值有有一一个个相相当当大大的的变变动动范范围围,约约为为(5%25%)t 左左右右。取取较较小小的的间间隙隙有有利利于于提提高高冲冲件件的的质质量量,取取较较大大的的间间隙隙则则有有利利于于提提高高模模具具的的寿寿命命。因因此此,在在保保证证冲冲件件质质量量的的前前提提下下,应应采采用用较较大大间间隙隙。According According to to the the table,table,proper proper gap gap has has the the great great changeable changeable range range about about(5%(5%25%)25%)t.Get the smaller gap will i
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