【正文】 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 6T 低碳鋼，低合金鋼，高強(qiáng)度鉛合金 4T 鈦 3T 鈦合金 4T 注： T—— 材料厚度。 彎曲方式通常用于沖壓模具。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 。 S—— 極限張力強(qiáng)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。在彎曲過程中這種恢復(fù)稱為回彈。磷青銅的回彈則在 10176。 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)，雙點壓力機(jī)，雙邊齒輪驅(qū)動壓力機(jī)，雙點單動壓力機(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)，單點單動壓力機(jī)，開式雙柱可傾壓力機(jī)，開式壓力機(jī)，四點式壓力機(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。 圖 9 典型通用壓力機(jī) 三動式壓力機(jī)具有和雙動式壓力機(jī)相同的內(nèi)、外滑塊。這裝置的設(shè)計是在沖壓行程的末端以很高壓力。 圖 10 典型液壓機(jī) 液壓機(jī)屬于壓力限定型的成形機(jī)械，液壓機(jī)的主要用途體現(xiàn)在沿滑塊路徑外力是必須保持恒定或處于精確攤制鋒成形技術(shù)領(lǐng) 域中。因此幾種液壓機(jī)驅(qū)動很容易就被制成復(fù)雜成形與切斷加工（拉深、擠壓、切斷、模鍛等）的單一機(jī)械，并且所要求的運(yùn)動可以容易地定位，彎扳機(jī)除了它的長床身之外基本是與開式壓力機(jī)棚同的，床身長度可為 6～ 20 英尺 (～ 6 米 )或更長，它基本上是用在尺寸大的鈑金零件上的各種類型的彎曲加工成形，它也可以使用不同整套的刀具分別進(jìn)行淺沖孔、切口與成形（見圖 11）。彎板機(jī)使用一個用在機(jī)械或液壓饑上的長模具，適用于小批量生產(chǎn)。 附件 2：外文原文 Stampng Die Design The 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 sheetmetal forming. Sheetmetal 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 today39。to 5176。 is simple, and it is adaptable to a wide variety of shapes, furthermore, the process can be easily automated. Die materials for press brakes may range from hardwood (for lowstrength materials and small production runs) to carbides. For most applications, carbonsteel or grayiron dies are generally used. 。to15176。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 bees smaller), the tensile strain at the outer fiber increases, and the material eventually cracks (Figure 5). Figure 4 Bending terminology Figure5 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 temperature Material Condition Soft Hard Aluminum alloys 0 6T Beryllium copper 0 4T Brass,lowleaded 0 2T Magnesium 5T 13T Steels Austenitic stanless 6T Lowcarbon,lowalloy,HSLA 4T Titanium 3T Titanium alloys 4T Note :T—— thickness of material Bend 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 by Lb= 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—— when R is less than 2T and when JR is