Φ35圓螺母止動墊圈沖孔落料復合模具設(shè)計【含UG三維及10張CAD圖】
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附錄A英 文 文 獻 翻 譯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 "sheet-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 floor 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 sheet-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 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 1.1 considers a simple forming process in which a cylindrical cup is produced from a circular blank.40Figure1. 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 contract in the circumferential direction, the sheet thickness remaining approximately constant Modes of sheet forming are shown in Figure 1.2.Figure1.2 Modes of sheet forming41論文題目Stretching is the term usually used to describe the deformation in which an element of sheet material is made to elongate in two 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 elongation 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 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 pressworked (stmped) parts, including all supportingand 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 guide 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 Figure1. 3.42Figure1.3 Typical single-station die for piercing hole 1—Lower shoe 2,5—Guide bushings 3—Cavity plate 4—Guid pin6—Spring-loaded stripper 7—Punch 8—Support plate 9—Punch bushing 10—Fan-shaped block 11—Fixed plate 12—Punch-holder plate 13—Backing plate14—Spring 15—Stepping bolts 16—Upper shoe 17—ShankA punch holder mounted to the upper shoe holds two round punches (male members of the die) which are guided by bushings inserted 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 the 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 from the punch. Spring-loaded43論文題目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 positioned 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 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 1.4. Note that, in bending, the outer fibers of the material are in tension, while the 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 vary 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 material eventually cracks (Figure 1.5).Figure 1.4Bending terminology44Figure1.5 Poisson effectThe minimum bend radius for various materials is given in Table 1.6 and it is usually expressed in terms of the thickness. such as 2 T, 3 T, 4T.Table 1.6 Minimum bend radius for various materials at room temperatureConditionMaterialSoft HardAluminum alloys 0 6TBeryllium copper 0 4TBrass,low-leaded 0 2TMagnesium 5T 13TSteelsAustenitic stanless 0.5T 6TLow-carbon,lowalloy,HSLA0.5T 4TTitanium 0.7T 3TTitanium alloys 2.6T 4T45論文題目Note :T——thickness of materialBend allowance as shown in Figure 4 is the length of the neutral axis in the bend and 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= α(R 十 kT)Where Lb——bend allowance, in (mm). α——bend angle, (radians) (deg). T——sheet thickness, in (mm).R——inside radius of bend, in (mm).k——0.33 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 bock[Figure 6(a)],is forced by a wedge-shaped punch into the block. This method, 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 1.6(b)] is cantilever loading of a beam. 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.46Figure 1.6 Bending methods46Bending 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/WWhere P-bending force, tons (for metric usage, multiply number of tons by 8.896 to obtain kilonewtons).K——die opening factor: 1.20 for a die opening of 16 times metal thickness, 1.33 for an opening of 8 times metal thickness.L——length of part, in.S——ultimate tensile strength, tons per square in.W——width of V or U die, in.T——metal thickness, in.For U bending (channel bending) 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 Figure1. 7). In bending, this recovery is called springback. Generally speaking, such a springback varies in sheet from 0.5°to 5°, depending upon finite modulus of elasticity, modes of bending, clearance of die and so on, but phosphor bronze may spring back from 10°to15°.47論文題目Figure1. 7 Springback during bendingMethods of reducing or eliminating springback in bending operations can be made according to the following operations, shown in Figure1. 8, and parts produced in bending die are also overbent through an angle equal to the springback angle with an undercut or relieved punch.Figure1.8 Methods of reducing or eliminating springbackFor the applications, there are many types of the presses, such as the single-action straight-slide eccentric mechanical press, punch press, hydro-former press, hydraulic press, press brake, triple-action press, turret press, two-point press, twin-drive press, two point single-action press, watch press, trimming press, closed-type single-action crank press, knuckle-lever press, one-point single-action press, open-back inclinable press, open-side press, four-point press, four-crank press,48flywheel-type screw press, friction screw press, straight-side single-action double-crank press, rocker-arm press, screw press and top-drive sheet-metal stamping automatic press and so on.49論文題目沖壓模具設(shè)計對于汽車行業(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行。如果自己沒有去這些大公司訪問,沒有站在巨大的機器旁,沒有感受到地 面的震顫沒有看巨大型的機器人的手臂吧零件從一個機器移動到另一個機器, 那么廠區(qū)的范圍與價值真是難以想象的。當然,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因 素是觀看大量的汽車板類零件被進行不同類型的板料成形加工。落料是簡單的 剪切完成的,然后進行不同類型的加工,諸如: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1.1 描述的是一個簡單的從圓坯料拉深成一個圓柱水杯的成形過程。圖1.1 板料成形一個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1.2 所示。50拉延通常是用來描述在板料平面上的兩個互相垂直的方向被拉長的板料的 單元體的變形原理的術(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,一個板料的單元體僅在一個方向上進行 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1.2 板料成形原理彎曲時當板料經(jīng)過沖模,即沖頭半徑加工成形時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平面張力拉長與收縮的典型實例。在一個壓力機沖程中用于在一塊板料上沖出一個或多個孔的一個完整的沖 壓模具可以歸類即制造商標準化為一個單工序沖孔模具,如圖1.3 所示。51論文題目圖1.3 典型的單工序沖孔模具1—下模座 2、5—導套 3—凹 模 4—導 桿 6—彈壓卸料板 7—凸 模 8—托 板 9—凸 模 護 套 10—扇形塊 11—固定板 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。導桿,或?qū)е?,是安裝在下模座上的。上模座則安裝有用于導桿滑動的導 套,分別裝有導套與導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凸模(模具中的突出部分),這 兩個圓形凸模則通過插入在卸料板上的導套進行導向。套筒,或凸模護套,是 用來保護沖頭,以免在沖壓過程中被卡住。在沖穿工件材料后,兩個沖頭便進 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)的兩個模具導套組成52的。因為沖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縮回,使工件 與工件剝離。一個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定位的擋 料塊等定位的。彎曲時一種最常見的成形工序當我們僅將目光移至汽車或電器上的部件, 或一個剪紙機或檔案柜上時,就會發(fā)現(xiàn)許多零件都是由彎曲成形的。彎曲不僅 可以用來成形法蘭、接頭、波紋,也可以提高零件的強度(通過增加零件的慣 性矩)。圖1 .4 彎曲術(shù)語彎 曲 中 所 用 的 術(shù) 語 , 如 圖 1.4 所 示 , 應 該 注 意 的 是 , 在 彎 曲 中 材 料 的 外 纖 維是處于拉應力狀態(tài),而材料的內(nèi)纖維則處于壓應力狀態(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)象可在彎曲一個矩形的橡膠板擦時容易觀察到的。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 弱 的 前 提 下 , 可 以 彎 曲 成 一 個 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?。饫w維的拉應力增加,材料最終斷53論文題目裂(參見圖1.5)。圖1.55 泊松效應不同材料的最小彎曲半徑參考表1。6,他通常是按照不同板厚來表示的, 諸如:2T ,3T,4T 等。表1.6 在室溫狀態(tài)下各種材料的最小彎曲半徑狀態(tài)材料軟 硬鋁合金 0 6T釹青銅合金,釹合金 0 4T黃銅,低鉛 0 2T鎂 5T 13T鋼奧氏體不銹鋼 0.5T 6T低碳鋼,低合金鋼,高強度鉛合金 0.5T 4T鈦 0.7T 3T鈦合金 2.6T 4T注:T——材料厚度。54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=α(R+kT)式中:L b——彎曲容許范圍,毫米; α——彎 曲角 度 ( 弧 度 ) , 度 ; T——金屬板厚,毫米; R——彎曲內(nèi)層半徑,毫米;k——當半徑R < 2T 時為0.33,當半徑 R> 2T 時為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 1.6(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,工件則被一個彈性加載墊片加 緊模具體上。圖1.6 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度的函數(shù),此彎曲力的計算式為:P=KLST2/W55論文題目式中: 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)時的開啟系數(shù)為1.20, 8倍材料厚度(8T)時的開啟系數(shù)為1.33;L——零件長度,英寸; S——極限張力強度,噸/平方英寸; W——V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?;貜棥K薪饘俨牧暇幸粋€固定的彈性模量,隨之而來的是塑性變形, 當 施 加 在 材 料 上 的 彎 曲 力 消 除 時 就 會 有 一 些 彈 性 恢 復 ( 見 圖 1.7) 。 在 彎 曲 過 程 中 這 種 恢 復 稱 為 回 彈 。 一 般 而 言 , 這 樣 的 回 彈 在 0.5°~ 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1.7 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 行 , 如 圖 1.8 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?性緩沖式彎曲模而被過度彎曲來減少或消除回彈。56圖1.8 減少或消除回彈的方法從應用角度來說,有許多類型的壓力機,諸如:閉式雙點偏心軸單動機械 壓力機,沖壓成形機,液壓成形壓力機,液壓機,彎板機,三動式壓力機,沖 ?;剞D(zhuǎn)壓力機,雙點壓力機,雙邊齒輪驅(qū)動壓力機,雙點單動壓力機,臺式壓 力機,切邊壓力機,閉式單動(曲柄)壓力機,肘桿式壓力機,單點單動壓力 機,開式雙柱可傾壓力機,開式壓力機,四點式壓力機,四曲柄壓力機,飛輪 式螺旋壓力機,摩擦傳動螺旋壓力機,閉式雙點單動雙曲柄壓力機,搖臂式壓 力機螺旋式壓力機和上傳動板料沖壓自動壓力機等。