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1、附件1:外文資料翻譯譯文沖壓模具設(shè)計(jì)對于汽車行業(yè)與電子行業(yè),各種各樣的板料零件都是有各種不同的成型工藝所生產(chǎn)出來的,這些均可以列入一般種類“板料成形”的范疇。板料成形(也稱為沖壓或壓力成形)經(jīng)常在廠區(qū)面積非常大的公司中進(jìn)行。如果自己沒有去這些大公司訪問,沒有站在巨大的機(jī)器旁,沒有感受到地面的震顫,沒有看巨大型的機(jī)器人的手臂吧零件從一個(gè)機(jī)器移動到另一個(gè)機(jī)器,那么廠區(qū)的范圍與價(jià)值真是難以想象的。當(dāng)然,一盤錄像帶或一部電視專題片不能反映出汽車沖壓流水線的宏大規(guī)模。站在這樣的流水線旁觀看的另一個(gè)因素是觀看大量的汽車板類零件被進(jìn)行不同類型的板料成形加工。落料是簡單的剪切完成的,然后進(jìn)行不同類型的加工,諸
2、如:彎曲、拉深、拉延、切斷、剪切等,每一種情況均要求特殊的、專門的模具。而且還有大量后續(xù)的加工工藝,在每一種情況下,均可以通過諸如拉深、拉延與彎曲等工藝不同的成形方法得到所希望的得到的形狀。根據(jù)板料平面的各種各樣的受應(yīng)力狀態(tài)的小板單元體所可以考慮到的變形情形描述三種成形,原理圖1描述的是一個(gè)簡單的從圓坯料拉深成一個(gè)圓柱水杯的成形過程。圖1 板料成形一個(gè)簡單的水杯拉深是從凸緣型坯料考慮的,即通過模具上沖頭的向下作用使材料被水平拉深。一個(gè)凸緣板料上的單元體在半徑方向上被限定,而板厚保持幾乎不變。板料成形的原理如圖2所示。拉延通常是用來描述在板料平面上的兩個(gè)互相垂直的方向被拉長的板料的單元體的變形原
3、理的術(shù)語。拉延的一種特殊形式,可以在大多數(shù)成形加工中遇到,即平面張力拉延。在這種情況下,一個(gè)板料的單元體僅在一個(gè)方向上進(jìn)行拉延,在拉長的方向上寬度沒有發(fā)生變化,但是在厚度上有明確的變化,即變薄。圖2 板料成形原理彎曲時(shí)當(dāng)板料經(jīng)過沖模,即沖頭半徑加工成形時(shí)所觀察到的變形原理,因此在定向的方向上受到改變,這種變形式一個(gè)平面張力拉長與收縮的典型實(shí)例。在一個(gè)壓力機(jī)沖程中用于在一塊板料上沖出一個(gè)或多個(gè)孔的一個(gè)完整的沖壓模具可以歸類即制造商標(biāo)準(zhǔn)化為一個(gè)單工序沖孔模具,如圖3所示。圖3 典型的單工序沖孔模具1下模座 2、5導(dǎo)套 3凹模 4導(dǎo)桿6彈壓卸料板 7凸模 8托板 9凸模護(hù)套 10扇形塊 11固定板
4、12凸模固定板 13墊塊 15階梯螺釘 16上模座 17模柄任何一個(gè)完整的沖壓模具都是有一副(或多副的組合)用于沖制工作的(沖壓)零件組成,包括:所有的支撐件部分與模具的工作部分零件,即構(gòu)成一副沖模。沖壓(術(shù)語)通常將完整壓制工具的凹模(母模)部分定義為模具。導(dǎo)桿,或?qū)е?,是安裝在下模座上的。上模座則安裝有用于導(dǎo)桿滑動的導(dǎo)套,分別裝有導(dǎo)套與導(dǎo)桿的上模座與下模座組合成為木架。模架有許多規(guī)格與結(jié)構(gòu)設(shè)計(jì)用于商業(yè)銷售。安裝在上模座上的凸模固定裝置固定兩個(gè)凸模(模具中的突出部分),這兩個(gè)圓形凸模則通過插入在卸料板上的導(dǎo)套進(jìn)行導(dǎo)向。套筒,或凸模護(hù)套,是用來保護(hù)沖頭,以免在沖壓過程中被卡住。在沖穿工件材料后
5、,兩個(gè)沖頭便進(jìn)入到凹模一定距離。凹模(母模)部分,即凹模,通常是由插入模具體內(nèi)的兩個(gè)模具導(dǎo)套組成的。因?yàn)闆_頭的直徑是被沖孔的直徑所要求的,所以有一定間隙的凹模直徑是大于沖頭直徑的。由于工件材料坯料或工件在沖制回程時(shí)與沖頭附連在一起,所以把材料從沖頭上剝離是必需的。彈壓卸料板則保持沖頭在沖制工件回程時(shí)縮回,使工件與工件剝離。一個(gè)沖制的工件通常是留在漏料槽內(nèi)的,漏料槽是由包含整個(gè)零件外輪廓的平板組成。模座是由銷釘支撐板以及其他的滑塊下行程時(shí)定位的擋料塊等定位的。彎曲時(shí)一種最常見的成形工序。當(dāng)我們僅將目光移至汽車或電器上的部件,或一個(gè)剪紙機(jī)或檔案柜上時(shí),就會發(fā)現(xiàn)許多零件都是由彎曲成形的。彎曲不僅可以
6、用來成形法蘭、接頭、波紋,也可以提高零件的強(qiáng)度(通過增加零件的慣性矩)。圖4 彎曲術(shù)語彎曲中所用的術(shù)語,如圖4所示,應(yīng)該注意的是,在彎曲中材料的外纖維是處于拉應(yīng)力狀態(tài),而材料的內(nèi)纖維則處于壓應(yīng)力狀態(tài)。由于泊松比原因,在外部區(qū)域的零件(彎曲長度L)是小于原始寬度,處于內(nèi)部區(qū)域的則比原始寬度大。這種現(xiàn)象可在彎曲一個(gè)矩形的橡膠板擦?xí)r容易觀察到的。最小彎曲半徑對于不同的金屬是變化的。一般而言,各種退火的金屬板在沒有斷裂或變?nèi)醯那疤嵯?,可以彎曲成一個(gè)等同金屬板厚的半徑。隨著R/T比值的減少(彎曲半徑對厚度的比值變?。?,外纖維的拉應(yīng)力增加,材料最終斷裂(參見圖5)。圖5 泊松效應(yīng)不同材料的最小彎曲半徑參考
7、表1,他通常是按照不同板厚來表示的,諸如:2T,3T,4T等。表1 在室溫狀態(tài)下各種材料的最小彎曲半徑材料狀態(tài)軟硬鋁合金06T釹青銅合金,釹合金04T黃銅,低鉛02T鎂5T13T鋼奧氏體不銹鋼0.5T6T低碳鋼,低合金鋼,高強(qiáng)度鉛合金0.5T4T鈦0.7T3T鈦合金2.6T4T注:T材料厚度。彎曲容許范圍,是指彎曲中的中性線(層)的長度,用來確定彎曲零件的坯料長度。然而,中性線(層)的位置是喲彎曲角度(正如在材料力學(xué)課本中所描述)來決定的。彎曲容許范圍(Lb)的近似的公式為:Lb=(R+kT) 式中:Lb彎曲容許范圍,毫米; 彎曲角度(弧度),度; T金屬板厚,毫米; R彎曲內(nèi)層半徑,毫米;
8、k當(dāng)半徑R2T時(shí)為0.33,當(dāng)半徑R2T時(shí)為0.50。彎曲方式通常用于沖壓模具。金屬鋼板或帶料,由V形支撐,參見圖6(a)在楔形沖頭的沖壓力作用下進(jìn)入V形模具內(nèi)彈簧加載壓花銷和零件之間的摩擦將會防止或減少零件在彎曲期間的邊緣滑移。棱邊彎曲,參見圖6(b)是懸臂橫梁式加載方式,彎曲沖頭對相對支撐的凹模上的金屬施加彎曲力。彎曲軸線是與彎曲模具的棱邊相平行的。在沖頭接觸工件之前,為了防止沖頭向下行程的位移,工件則被一個(gè)彈性加載墊片加緊模具體上。圖6 彎曲方式彎曲力的大小是可以通過對一根矩形橫梁的簡單彎曲的工藝過程的確定來估算。在此情況下的彎曲力是材料強(qiáng)度的函數(shù),此彎曲力的計(jì)算式為:P=KLST2/W
9、式中:P彎曲力,噸(對于米制使用單位,噸乘以8.896數(shù)值以得到千牛頓單位); K模具開啟系數(shù):16倍材料厚度(16T)時(shí)的開啟系數(shù)為1.20,8倍材料厚度(8T)時(shí)的開啟系數(shù)為1.33; L零件長度,英寸; S極限張力強(qiáng)度,噸/平方英寸; WV或U形模具的寬度,英寸; T材料厚度,英寸。對于U形彎曲(槽形彎曲),彎曲力大約是V形彎曲所需要的彎曲壓力的兩倍,棱邊彎曲則大約是V形彎曲所需要的彎曲壓力的1/2?;貜?。所有金屬材料均有一個(gè)固定的彈性模量,隨之而來的是塑性變形,當(dāng)施加在材料上的彎曲力消除時(shí)就會有一些彈性恢復(fù)(見圖7)。在彎曲過程中這種恢復(fù)稱為回彈。一般而言,這樣的回彈在0.5°
10、;5°之間變化,取決于固定的彈性模量、彎曲方式、模具間隙等。磷青銅的回彈則在10°15°之間。圖7 彎曲中的回彈減少或消除在彎曲工序中回彈方法可以根據(jù)下列工藝方法進(jìn)行,如圖8所示,在彎曲模具中產(chǎn)生的零件也可以通過等同回彈角度彎曲模上挖凹?;驈椥跃彌_式彎曲模而被過度彎曲來減少或消除回彈。圖8 減少或消除回彈的方法從應(yīng)用角度來說,有許多類型的壓力機(jī),諸如:閉式雙點(diǎn)偏心軸單動機(jī)械壓力機(jī),沖壓成形機(jī),液壓成形壓力機(jī),液壓機(jī),彎板機(jī),三動式壓力機(jī),沖?;剞D(zhuǎn)壓力機(jī),雙點(diǎn)壓力機(jī),雙邊齒輪驅(qū)動壓力機(jī),雙點(diǎn)單動壓力機(jī),臺式壓力機(jī),切邊壓力機(jī),閉式單動(曲柄)壓力機(jī),肘桿式壓力機(jī),單
11、點(diǎn)單動壓力機(jī),開式雙柱可傾壓力機(jī),開式壓力機(jī),四點(diǎn)式壓力機(jī),四曲柄壓力機(jī),飛輪式螺旋壓力機(jī),摩擦傳動螺旋壓力機(jī),閉式雙點(diǎn)單動雙曲柄壓力機(jī),搖臂式壓力機(jī)螺旋式壓力機(jī)和上傳動板料沖壓自動壓力機(jī)等。附件2:外文原文Stamping Die DesignThe wide variety of sheet metal parts for both the automobile and electronic industries is produced by numerous forming processes that fall into the generic category of "sh
12、eet-metal forming". Sheet-metal forming ( also called stamping or pressing )is often carried out in large facilities hundreds of yards long.It is hard to imagine the scope and cost of these facilities without visiting an automobile factory, standing next to the gigantic machines, feeling the fl
13、oor vibrate, and watching heavy duty robotic manipulators move the parts from one machine to another. Certainly, a videotape or television special cannot convey the scale of today's automobile stamping lines. Another factor that one sees standing next to such lines is the number of different she
14、et-forming operations that automobile panels go through. Blanks are created by simple shearing, but from then on a wide variety of bending, drawing, stretching, cropping , and trimming takes place, each requiring a special, custom-made die.Despite this wide variety of sub-processes, in each case the
15、 desired shapes are achieved by the modes of deformation known as drawing, stretching, and bending. The three modes can be illustrated by considering the deformation of small sheet elements subjected to various states of stress in the plane of the sheet. Figure 1 considers a simple forming process i
16、n which a cylindrical cup is produced from a circular blank.Figure 1 Sheet forming a simple cupDrawing is observed in the blank flange as it is being drawn horizontally through the die by the downward action of the punch. A sheet element in the flange is made to elongate in the radial direction and
17、contract in the circumferential direction, the sheet thickness remaining approximately constant Modes of sheet forming are shown in Figure 2.Figure2 Modes of sheet formingStretching is the term usually used to describe the deformation in which an element of sheet material is made to elongate in two
18、perpendicular directions in the sheet plane. A special form of stretching, which is encountered in most forming operations, is plane strain stretching. In this case, a sheet element is made to stretch in one direction only, with no change in dimension in the direction normal to the direction of elon
19、gation but a definite change in thickness, that is, thinning.Bending is the mode of deformation observed when the sheet material is made to go over a die or punch radius, thus suffering a change in orientation. The deformation is an example of plane strain elongation and contractionA complete press
20、tool for cutting a hole or multi-holes in sheet material at one stroke of the press as classified and standardized by a large manufacturer as a single-station piercing die is shown in Figure3.Any complete press tool, consisting of a pair( or a combination of pars ) of mating member for producing pre
21、ssworked (stmped)parts, including all supporting and actuating elements of the tool, is a die. Pressworking terminology commonly defines the female part of any complete press tool as a die.The guide pins, or posts, are mounted in the lower shoe. The upper shoe contains bushings which slide on the gu
22、ide pins. The assembly of the lower and upper shoes with guide pins and bushings is a die set. Die sets in many sizes and designs are commercially available. The guide pins are shown in Figure 3. Figure3 Typical single-station die for piercing hole1Lower shoe 2,5Guide bushings 3Cavity plate 4Guid pi
23、n 6Spring-loaded stripper 7Punch 8Support plate 9Punch bushing 10Fan-shaped block 11Fixed plate 12Punch-holder plate 13Backing plate 14Spring 15Stepping bolts 16Upper shoe 17ShankA punch holder mounted to the upper shoe holds two round punches (male members of the die) which are guided by bushings i
24、nserted in the stripper. A sleeve, or quill, encloses one punch to prevent its buckling under pressure from the ram of the press. After penetration of the work material, the two punches enter the die bushings for a slight distance.The female member, or die, consists of two die bushings inserted in t
25、he die block. Since this press tool punches holes to the diameters required, the diameters of the die bushings are larger than those of the punches by the amount of clearance.Since the work material stock or workpiece can cling to a punch on the upstroke, it may be necessary to strip the material fr
26、om the punch. Spring-loaded strippers hold the work material against the die block until the punches are withdrawn from the punched holes. A workpiece to be pierced is commonly held and located in a nest (Figure 2-3) composed of flat plates shaped to encircle the outside part contours. Stock is posi
27、tioned in dies by pins, blocks, or other types of stops for locating before the downstroke of the ram.Bending is one of the most common forming operations. We merely have to look at the components in an automobile or an appliance-or at a paper clip or a file cabinet-to appreciate how many parts are
28、shaped by bending. Bending is used not only to form flanges, seams, and corrugations but also to impart stiffness to the part ( by increasing its moment of inertia ).The terminology used in bending is shown in Figure 4. Note that, in bending, the outer fibers of the material are in tension, while th
29、e inner fibers are in compression. Because of the Poisson's ratio, the width of the part (bend length, L) in the outer region is smaller, and in the inner region is larger than the original width. This phenomenon may easily be observed by bending a rectangular rubber eraser. Minimum bend radii v
30、ary for different metals, generally, different annealed metals can be bent to a radius equal to the thickness of the metal without cracking or weakening. As R/T decreases (the ratio of the bend radius to the thickness becomes smaller), the tensile strain at the outer fiber increases, and the materia
31、l eventually cracks (Figure 5). Figure 4 Bending terminologyFigure5 Poisson effect The minimum bend radius for various materials is given in Table 1 and it is usually expressed in terms of the thickness. such as 2 T, 3 T, 4T.Table 1 Minimum bend radius for various materials at room temperatureMateri
32、alConditionSoft HardAluminum alloys06TBeryllium copper04TBrass,low-leaded02TMagnesium 5T13TSteelsAustenitic stanless0.5T6TLow-carbon,lowalloy,HSLA0.5T4TTitanium0.7T3TTitanium alloys2.6T4TNote :Tthickness of material Bend allowance as shown in Figure 4 is the length of the neutral axis in the bend an
33、d is used to determine the blank length for a bent part. However, the position of the neutral axis depends on the radius and angle of bend (as described in texts on mechanics of materials).An approximate formula for the bend allowance, Lb is given byLb= (R十kT) Where Lbbend allowance, in (mm). bend a
34、ngle, (radians) (deg). Tsheet thickness, in (mm). Rinside radius of bend, in (mm). k0.33 when R is less than 2T and 0.50 when JR is more than 2T.Bend methods arc commonly used in press tool. Metal sheet or strip, supported by-V bockFigure 6(a),is forced by a wedge-shaped punch into the block. This m
35、ethod, termed V bending, produces a bend having an included angle which may be acute, obtuse, or 90°.Friction between a spring-loaded knurled pin in the vee die and the part will prevent or reduce side creep of the part during its bending. Edge bending Figure 6(b) is cantilever loading of a bea
36、m. The bending punch forces the metal against the supporting die. The bend axis is parallel to the edge of the die. The workpiece is clamped to the die block by a spring-loaded pad before the punch contacts the workpiece to prevent its movement during downward travel of the punch.Figure 6 Bending me
37、thodsBending Force can be estimated by assuming the process of simple bending of a rectangular beam. The bending force in that case is a function of the strength of the material. The calculation of bending force is as follows:P=KLST2/W Where P-bending force, tons (for metric usage, multiply number o
38、f tons by 8.896 to obtain kilonewtons).Kdie opening factor: 1.20 for a die opening of 16 times metal thickness, 1.33 for an opening of 8 times metal thickness.Llength of part, in.Sultimate tensile strength, tons per square in.Wwidth of V or U die, in.Tmetal thickness, in.For U bending (channel bendi
39、ng) pressures will be approximately twice those required for V bending, edge bending requires about one-half those needed for V bending.Springback in that all materials have a finite modulus of elasticity, plastic deformation is followed, when bending pressure on metal is removed, by some elastic recovery (see Figure 7). In bending, this
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