機械制造專業(yè)外文翻譯--新型四分區(qū)錐形壓邊力摩擦輔助拉深的工藝

1、<p>　　畢業(yè)設(shè)計(論文)外文資料翻譯</p><p>　　系　　部： 機械工程系 </p><p>　　專 業(yè)： 機械制造及自動化 </p><p>　　姓 名： </p><p>　　學(xué) 號：

2、 </p><p>　　外文出處: Journal of Materials Processing Technology，159(2005),418–425. </p><p>　　附 件： 1.外文資料翻譯譯文；2.外文原文。 </p><p>　　附件1：外文

3、資料翻譯譯文</p><p>　　新型四分區(qū)錐形壓邊力摩擦輔助拉深的工藝</p><p>　　摘要：本文提出了一種摩擦輔助拉深的新技術(shù)。金屬壓邊圈設(shè)計可分為兩層：一層為不動層，或稱基層，由四個5°錐角的平面組成；另一層為移動層，分為四個錐形部分。在適當(dāng)?shù)膲哼吜ο?，這四個部分能通過一種專門設(shè)計的壓緊工具勻速徑向移動到模腔，這種壓邊裝置的主要功能是利用板料和壓邊圈之間的在有效拉深方向

4、上的摩擦力，就如在Maslennikov過程中利用的橡膠圈的功能。使用一個輔助的金屬沖壓器在拉深過程中在液壓缸的幫助下提供一個恒定的拉深力來實現(xiàn)有效的拉深變形。所提出工藝的優(yōu)缺特點主要研究拉深的機構(gòu)和拉深條件的影響。雖然成功制造拉深比率為3.76的深杯狀體已驗證了當(dāng)前技術(shù)的可行性，然而，提高拉深效率還需要進(jìn)一步研究。</p><p>　　關(guān)鍵詞 金屬板料成型 摩擦輔助拉深 拉深 分塊壓邊圈</p&g

5、t;<p><b>　　1. 介紹</b></p><p>　　在傳統(tǒng)的拉深法中，第一階段的拉深很難超過單位杯高度與直徑比率為2.2的拉深比率極限。提出的提高變形極限的解決方案一般分為三類：改變需成型金屬板的材料特性；改變應(yīng)力狀態(tài)；改變摩擦狀態(tài)?；谶@些基本解決方案，已提出了很多特殊工藝來提高拉深比率極限[1-10]。使用這些工藝，在材料流動應(yīng)力可控制在材料極限強度以下時來獲

6、得巨大的塑性張力。在這些拉深工藝中，所謂的Maslennikov工藝[11]是一種特殊的方式，其巧妙的利用置于杯形件中的橡膠圈作為壓力介質(zhì)產(chǎn)生毛坯拉深變形。該過程屬于上述的第三類方案，即改變摩擦的狀態(tài)。不同于傳統(tǒng)方法，該工藝?yán)妹靼宀暮拖鹉z圈之間的摩擦力實現(xiàn)深拉深。由于該拉深方式是通過徑向的壓力實現(xiàn)的，就能避免凸模圓角部分的破裂。但是，對于薄板，凸緣部分仍然存在圓周破裂。這種破裂曾被認(rèn)為是由于壓力沿橡膠圈和毛坯[12，13] 的半徑方

7、向分布不均勻而產(chǎn)生的防滑點。Maslennikov工藝的另一個缺陷是，因為誘導(dǎo)摩擦力不足而導(dǎo)致高變形阻力毛坯不能拉深。此外，橡膠的使用壽命短，而拉深又要求有較高的壓力。</p><p>　　為了克服這些缺陷， Hassan et al [14] 。提出了新的建議：用一個分為四部分的壓邊圈取代在Maslennikov工藝中使用的橡膠圈。該技術(shù)進(jìn)行深拉深的可行性已被驗證，但是，有一個關(guān)鍵點約束著該裝置的應(yīng)用。那就是由

8、于凸模材料流入壓邊分區(qū)之間的空隙而產(chǎn)生起皺，如圖1(a)所示。這個問題可以通過在這四個分區(qū)[15]之間的間隙中插入四小楔子得以解決。新的壓邊圈分為八個部分(四小楔子和四個拉深分區(qū))取得了良好的效果。但是不幸的是，在使用薄板材的情況下，拉深部分和四個楔子的邊緣部分由于局部過強的剪切力而出現(xiàn)裂痕，如圖1((b)中所示。</p><p>　　在目前的研究論文中最新提出，用一個分為四部分的雙層錐形壓邊圈來消除局部褶皺和嚴(yán)

9、重剪切變形區(qū)域這些不足。該論文細(xì)致探討了變形機制和拉深條件的影響，并證實了現(xiàn)今深拉深技術(shù)的可行性。</p><p>　　（a四分塊壓邊圈下的局部起皺、b八分塊壓邊圈下的局部剪切區(qū)）</p><p>　　圖1 原摩擦輔助拉深觀察到的缺陷</p><p>　　2. 四分區(qū)錐形壓邊圈的構(gòu)造和拉深機制</p><p>　　圖2(a) 所示為上述錐

10、形壓邊圈示意圖。它由一個固定的底座和四個成5°微斜錐形角的位面組成。拉深部分能勻速的在底座的錐形面上沿半徑方向的滑動。四個滑配合的楔片被用來引導(dǎo)這些拉深部分在固定底座上的運動。</p><p>　　理解拉深機制和壓邊圈的復(fù)合運動至關(guān)重要。拉深過程的第一步中，當(dāng)兩個端面分區(qū)在A方向上呈沿半徑方向位移時，變形便開始了，如圖2(b)所示。另外兩個部分在B方向上反向進(jìn)行復(fù)合運動，即與圖2(b)中所示的拉深方向相

11、反，向下和沿半徑方向向外運動。因此，毛坯板材和模具在A方向上上升，而在B方向上，如圖2(d)所示，毛坯板材和兩個拉深部分并沒有接觸。此時，邊緣有50%并不受制于壓邊圈。另一方面，A方向上的兩個拉深部分不斷上升至模具的開口處，兩者與毛坯板材有輕微的接觸，如圖2(c)所示。A方向上產(chǎn)生的摩擦力迫使毛坯變形并移向模具的開口處，同時，B方向上的兩個拉深部分產(chǎn)生一個反向的摩擦力使毛坯變形。所以，這種技術(shù)成功地消除了八個部分組成的壓邊圈帶來的局部強

12、烈剪切變形。然而，B方向上的毛坯邊緣由于受到圓周壓力作用而出現(xiàn)了褶皺。</p><p>　　在第二步拉深中，B方向上的壓邊圈做沿半徑方向換位轉(zhuǎn)移，與此同時，在A方向上的兩個拉深部分以于第一步中相似的方式做復(fù)合運動。因此，第一步中B方向上產(chǎn)生的褶皺被同時校正了。重復(fù)上述兩個步驟，就能成功制造出深杯形件。</p><p>　　圖2 四分區(qū)錐形壓邊圈的組成和運動示意圖</p>&

13、lt;p><b>　　3. 實驗準(zhǔn)備</b></p><p>　　3.1. 測試設(shè)備</p><p>　　圖3是試驗設(shè)備的主要組成部分的示意圖。毛坯變形需要足夠的壓邊力F1， 而沖壓力F2主要起到提高杯形件尺寸準(zhǔn)確性和幫助變形拉深的作用。合適的壓邊力F1由壓力閥17控制，合適的沖力F2由壓力閥16控制。拉深部件沿半徑方向在0-2毫米范圍內(nèi)的位移運動由測微儀1

14、3和四個調(diào)整銷11控制。壓緊工具 5 應(yīng)該在每次拉深操作后旋轉(zhuǎn)90度來改變強制性半徑方向替代運動的方向和毛坯與壓邊圈之間的壓力。實驗裝置裝配在一臺水壓機上。該水壓機能軸向進(jìn)行多范圍速度的運動，并能產(chǎn)生最大為100kN的壓力，而一臺單獨的泵所能產(chǎn)生的最大沖壓力也只有10 kN。試驗裝置尺寸和最佳力度見表1。</p><p>　　1拉深滑塊,2液壓缸,3,液壓,4擠壓墊,5壓緊工具,6模具,7 毛坯,8錐形邊壓邊圈,

15、9壓邊基座,10沖頭， 11調(diào)整銷, 12彈簧, 13測微儀, 14模具, 15工作臺,16壓力閥,17減壓閥。</p><p>　　圖3 拉深試驗設(shè)備示意圖;</p><p>　　表1 工具尺寸和實驗工況</p><p>　　3.2.實驗材料和實驗條件</p><p>　　使用0.5毫米厚度的柔軟的鋁((Al-CO)制毛坯作為試驗材料。

16、表2中所列數(shù)據(jù)為單軸張力測試中得到的材料的屬性常數(shù)F， n和r。當(dāng)毛坯的直徑分別為86和110時，拉深比率由2.87變?yōu)?.67。</p><p>　　為了研究毛坯變形的情況，在毛坯表面預(yù)先標(biāo)注出2毫米的同心圈，如圖4(a)所示。其中，最小的圓直徑為28毫米，最大的為80毫米。此外，還在毛坯表面標(biāo)注出A， B， C三個沿半徑的方向。在奇數(shù)/偶數(shù)次拉深時，部件分別在A/B方向上進(jìn)行替換移動，而部件C和壓邊圈各部分的

17、銜接邊界重合。</p><p>　　為了研究在杯側(cè)壁的格柵的變形，在直徑為110毫米的毛坯上標(biāo)示出間隔為5毫米的同心圓和五條間隔為22.5 °圓周角的半徑，如圖4(b)所示。45 °和-45°的半徑方向與指示邊界C重合，而零度方向為B方向，該方向上在偶數(shù)次拉深時受力變形。毛坯板材和壓邊圈之間干燥的摩擦有利于增加產(chǎn)生的摩擦力。不過，特氟隆影片(PTFE)被用作在毛坯板材和模具之間的固體

18、潤滑劑，來減小摩擦力。 </p><p>　?。╝） 拉深率2.87，板徑86mm （b） 拉深率3.67，板徑110 mm</p><p>　　圖4 板材上標(biāo)明的圓形柵格和方向</p><p>　　表2 柔軟的鋁制毛坯的機械特性和尺寸</p><p>　　4. 結(jié)果討論（略）</p><p>　　5. 目

19、前的深沖壓技術(shù)的可行性</p><p>　　圖5、圖6為已拉深杯形件；前者在50次拉深之后側(cè)壁C方向（±45°方向）出現(xiàn)弧坑狀缺陷。在制作過程中，C方向上板材的運動比B、A方向上的程度大，因此板材撞擊到模具開口處的帶扣而在沖壓和模具相分離時產(chǎn)生凹陷。然而，這個凹陷是可以被消除的：每隔一次拉深，把毛坯板材就銜接邊緣方向旋轉(zhuǎn)45°。這個簡單的技術(shù)幫助制造出了64毫米高3.67比率的杯形件

20、，如圖14所示。這樣的杯形件需要經(jīng)過100次的拉深，但是也證實了目前的依靠摩擦力的深拉深技術(shù)具有可行性。</p><p>　　圖5 C向上的弧坑狀缺陷</p><p>　　圖6 成功的杯形件例子(β=3.67，杯形件高度=64 mm，N=100)</p><p><b>　　6. 結(jié)論</b></p><p>　　

21、在借助摩擦力實現(xiàn)深拉深的技術(shù)方面，提出了一種新的方法來實現(xiàn)深杯形件的制造，即借助一個由四個錐形部分組成的壓邊圈。這種新設(shè)備克服了傳統(tǒng)的四部分或八部分構(gòu)成的壓邊圈會產(chǎn)生局部褶皺和劇烈的剪切變形等問題。拉深機制和拉深條件的影響也被細(xì)致的觀察了。當(dāng)壓邊力大于80kN，輔助沖壓力大于4kN時，拉深效率有顯著提高。這種技術(shù)能成功制造出比率為3.67的深杯形件，這也證實了目前改良技術(shù)的可行性。由于每次拉深壓邊圈沿半徑方向的位移被限制在1毫米，制造過

22、程需要100次拉深。但是，在該工藝中，自始至終只使用了一套剛性工具，加工時間也可由增加每分鐘的沖壓次數(shù)來縮短。因此，該工藝便于小批量深杯形件的生產(chǎn)。</p><p>　　附件2：外文原文（復(fù)印件）</p><p>　　A novel process on friction aided deep drawing using</p><p>　　tapered blan

23、k holder divided into four segments</p><p><b>　　Abstract</b></p><p>　　A new technique on friction aided deep drawing has been proposed. A metal blank holder was designed to be of two

24、 layers: stationary layer or base with four planes of 5? taper angle and moving layer divided into four tapered segments. Under appropriate blank holding force, these four segments can move radically to the die opening w

25、ith a constant speed by using a specially designed compression tool. The main function of this developed blank holding device is adopting the frictional force between t</p><p>　　1. Introduction</p>&l

26、t;p>　　The limiting drawing ratio achieved by the ?rst stage drawing in conventional deep drawing method seldom exceeds 2.2 which corresponds to the cup height to diameter ratio of about unity. Solutions proposed for i

27、ncreasing the forming limit generally fall into three categories; change</p><p>　　in the material properties of the sheet metal being formed, change in the stress state and change in the frictional state. Ba

28、sed on these fundamental solutions, many special processes have been proposed to increase the limiting drawing ratio [1–10]. In these processes, large plastic strains could be achieved when the low stress of material can

29、 be controlled in the range below the ultimate strength of material. Among these deep drawing processes the so-called Maslennikov process [11] is a unique </p><p>　　medium to generate drawing deformation of

30、a blank. This process belongs to the third category, i.e. change in the frictional state; the frictional force between the blank sheet and the rubber ring is used to achieve deep drawing unlike the conventional method. B

31、ecause the drawing of the blank</p><p>　　is carried out by the radial compressive force, the fracture at the punch pro?le portion can be avoided. However, for thin sheets, circumferential fracture has been o

32、bserved at the ?ange portion. The reason behind such fracture was attributed to the existence of a non-slip point at the ?ange</p><p>　　due to the difference in the radial velocity distributions of the rubbe

33、r ring and blank [12,13]. As another defect of the Maslennikov process, blanks of high deformation resistance cannot be drawn because the induced frictional force is not sufficient. Moreover, the lifetime of the rubber i

34、s short and very high pressure is required for drawing.</p><p>　　To overcome these decencies, Hassan et al. [14] have proposed to use a blank holder divided into four segments instead of the rubber ring used

35、 in the Maslennikov process.The possibility of the deep drawing with such technique has been con?rmed, however, there was one criticism limiting the application of such proposed device. That is occurrence of wrinkles due

36、 to ?owing of ?ange material into the gaps between the blank holder segments as shown in Fig. 1(a).Such a problem was overcome by ?tting f</p><p>　　Fig. 1. Defects observed in the previous friction aided dee

37、p drawing methods.</p><p>　　in Fig. 1(b) was observed due to the localized intensive shear deformation at the boundaries between the drawing segments and the four small wedges.</p><p>　　In the p

38、resent paper, a two-layered tapered blank holder divided into four segments was newly proposed to eliminate the defects of localized wrinkling and intensive shear deformation regions. The deformation mechanism and the ef

39、fects of drawing conditions are mainly investigated in detail and the possibility of the present deep drawing method is con?rmed.</p><p>　　Fig. 2. Schematic of construction and movement of tapered blank hold

40、er divided into four segments.</p><p>　　drawing segments that have similar planes of slightly taper angle of 5?, the drawing segments can slide radially under a constant speed over the tapered surfaces of th

41、e stationary base. Four keys with sliding ?t are used for guiding the motion of these segments on the stationary base.</p><p>　　It is important to understand the drawing mechanism and the compound motion of

42、the blank holder segments. In the ?rst drawing step, deformation starts when two facing segments receive radial displacement in the A-direction as shown in Fig. 2(b). The other two segments in the B-direction move in the

43、 reverse direction with compound motion; downward and radially outward opposite to the drawing direction as shown in Fig. 2(d). Due to this action, the blank sheet and the die in the A-direction are li</p><p&g

44、t;　　In the second drawing step, the blank holder segments in the B-direction receive radial displacement, while the other two segments in the A-direction move in a compound motion in a similar manner to the ?rst drawing

45、step. As a resultwrinkles generated in the B-direction in the ?rst drawing step will be simultaneously corrected. Therefore, complete and successful deep cups can be obtained by repeating these two steps to a certain num

46、ber of drawings.</p><p>　　3. Experimental setup</p><p>　　3.1. Test equipment</p><p>　　Fig. 3 is a schematic diagram which shows the essential elements of the test equipment. A suffi

47、cient blank holding force F1 is mainly required for the deformation of blank, while the punch force F2 is mainly added to enhance the dimensional accuracy of the drawn cup and to help partially the drawing deformation. T

48、he blank holding force F1 is controlled by the pressure valve 17 to obtain appropriate force, while the punch force F2 is controlled by the valve 16 for the proper use. The radial displ</p><p>　　Fig. 3. Sche

49、matic diagram showing equipment used for deep drawing test; 1-Press ram, 2-Hydraulic cylinder, 3-Oil pressure, 4-Dummy block, 5-Compression tool, 6-Die, 7-Blank, 8-Tapered blank holder, 9-Blank holder stationary base, 10

50、-Punch, 11-Adjusting pin, 12-Spring, 13-Dial gauge, 14-Container, 15-Die set, 16-Control valve, 17-Relief valve.</p><p><b>　　Table 1</b></p><p>　　Tool dimensions and experimental con

51、ditions</p><p>　　ments. The test rig is assembled on a hydraulic press, which has multi-ranges of axial speeds and maximum compression force of 1000 κN, while the maximum punch force given by a separate pump

52、 is 10 kN. The test rig dimensions and the optimum force conditions are listed in Table 1.</p><p>　　3.2. Test material and experimental conditions</p><p>　　Soft aluminum (Al–O) blanks of 0.5mm t

53、hickness was used as a testing material. The material constants F, n and r.</p><p><b>　　Table 2</b></p><p>　　Mechanical properties and dimensions of soft aluminum blanks (Al–O)</p

54、><p>　　determined from uneasily tension test are listed in Table 2.The blank diameter was changed as 86 and 110 which give drawing ratios of 2.87 and 3.67.</p><p>　　In order to investigate the defo

55、rmation behavior of blank,concentric circles of 2mm apart were initially marked on the blank surface as shown in Fig. 4(a). The smallest circle diameter is 28mm and the biggest one is 80mm. In addition to that, three rad

56、ial directions A, B and C are marked on the blank surface. Directions A and B receive imposed radial displacement during the odd and the even numbers of drawing respectively, while the direction C corresponds to the boun

57、dary between blank holder se</p><p>　　To study the distortion of grids at cup side wall, concentric circles of 5mm apart and ?ve radial lines of 22.5? angular distances were marked on the blank of 110mm in d

58、iameter as shown in Fig. 4(b). The radial directions 45? and ?45? correspond to the boundary directions C, while zero direction is located to be in consistent with B-direction which receives imposed deformation at the ev

59、en number of drawing.Dry friction condition between blank sheet and blank holder segments is necessary to incre</p><p>　　Fig. 4. Circular grids and prescribed directions marked on blanks.</p><p>

60、;　　4. Results and discussion</p><p>　　5. Possibility of the present deep drawing process</p><p>　　Examples of drawn cups are shown in Figs. 5 and 6;the former shows defects like a crater observe

61、d at the cup sidewall at the direction C (±45? directions) after 50 times drawing operations. At this stage of drawing, the radial in ?ow of material in the C-directions is greater than those in the directions B and

62、 A. Therefore, the material coming to the die opening buckles and makes craters in the clearance between punch and die. However, the craters could be eliminated by rotating the blank sheet </p><p>　　Fig. 5.

63、Craters defect observed in C-directions.</p><p>　　Fig. 6. An example of a successful cup (β = 3.67, cup height = 64mm,</p><p><b>　　N = 100).</b></p><p>　　6. Conclusions&

64、lt;/p><p>　　On the friction aided deep drawing process, a blank holder divided into four tapered segments has been newly developed as a method to obtain successful deep cups. This was achieved by overcoming the

65、 defects of localized wrinkling and intensive shear defamation observed when using ?at blank holder divided into four or eight segments developed previously. The drawing mechanism and the effects of drawing conditions ha