1.翻邊成形工藝
翻邊是將工件孔邊緣或外緣在模具的作用下,翻邊豎立邊緣的冷沖工序。根據(jù)工件邊緣的性質(zhì),翻邊還可以分為孔翻邊和外緣翻邊,包括圓孔和非圓孔翻邊;外凸曲線和內(nèi)凹曲線翻邊;平面和曲面翻邊等。當工件的邊緣為一條直線時,翻邊變形成為彎曲變形,所以彎曲是翻邊的種特殊形式。由此可見,在非封閉曲線翻邊中,防止工件側(cè)滑,是翻邊質(zhì)量的關鍵,在設計這類模具時,確保獲得較大的初始預壓力是非常必要的。目前常規(guī)的彈性元件,在預壓力和工作行程上都難以滿足要求,而氮氣彈簧卻能很容易滿足工藝需要,它具有足夠大的行程,具有足夠大的彈壓力可供選擇,都不需要預緊,可以達到設計者的要求,從而非?煽亢头(wěn)定地翻邊工件尺寸精度和成形質(zhì)量。當今冷沖壓工藝中,常見的翻邊質(zhì)量問題,大部分是由于工件預壓不緊所造成的,尤其是在汽車覆蓋件翻邊中,更為常見。氮氣彈簧的出現(xiàn)為有效解決這個問題。開拓了光明的前景。
起伏成形是一種使材料拉伸,形成局部的凹進或凸起,改變毛坯形狀的冷沖壓工藝方法,它主要用于壓制加強筋,來提高工件的剛度,減輕重量。對于某些具有連續(xù)凸筋的零件,由于受到材料延伸率的限制,難以一次壓筋成形,采用氮氣彈簧可以在一套模具中,根據(jù)不同的行程長度,分段階梯成形,非常有效地解決這種問題,提高沖壓生產(chǎn)率。解決這一類零件的問題主要是能夠很好地定位,同時還能使零件獲得預成形,完全消除了材料在成形過程中,相互牽制作用,有效地材料成形的順序,零件的質(zhì)量。
2.沖裁卸料、頂件與整形
沖裁是利用沖模使材料分離成兩部分的冷沖壓工序,將工件或廢料從凸模上卸下稱為卸料,將工件或廢料從凹模中順著沖裁方向推出稱為推件,逆著沖裁方向從凹模中頂出稱為頂件。這是在沖裁工藝中極為常見的動作。但是這三種動作不一定同時存在。便提高沖裁刃口壽命,正確選用和設計卸料裝置,對沖裁件的質(zhì)量是非常重要的。采用頂件器頂件,或是對于密集沖頭的沖裁件,往往由于模具空間比較小,頂件力比較大,給模具設計帶來一定難度,影響沖制件的質(zhì)量。在某些情況下,如果卸料力加劇模具刃口磨損。采用氮氣彈簧卸料或頂件,由于它的彈壓力大,占據(jù)的模具空間很小,卸料力和頂件力又很容易達到均衡狀態(tài),因為卸料板或頂件板均可以同時均衡地與氮氣彈簧接觸,布受力,從而非常平穩(wěn)地將工件頂出或?qū)U料卸出,確保工件的平直性,減少沖頭拆斷和磨損的可能性,提高了沖頭的壽命,模具設計也是非常簡單,尤其是對于密集型沖頭的沖壓件,更顯出它的優(yōu)點。例如發(fā)動機氣缸墊一類的零件,采用氮氣彈簧能有效地解決,模具空間小與要求卸料力大小的矛盾。甚至可以將模座作為氮氣彈簧的氣室加以利用,減小氮氣彈簧占有的空間。
中譯英:
1 Flanging forming process
Flanging is the workpiece hole edge or rim in the mold under the action of vertical edges, flanging cold stamping process. According to the properties of the workpiece edge, flanging can be also divided into the hole and the outer edge flanging, including a round hole and a round hole flanging; convex curve and a concave curve flanging; flat and curved flanging process. When the edge of the workpiece to a straight line, flanging deformation becomes bending deformation, so is the special form of bending flanging. Thus, in a closed curve flanging, prevents the workpiece slip, is to ensure that the flanging quality the key, in the design of this kind of mold, to ensure the availability of larger initial pre stress is very necessary. The current conventional elastic element, the preload and the working stroke are difficult to meet the requirements, and the gas spring can easily meet the technological requirements, it has a sufficiently large stroke, with a large bomb pressure are available, without pretension, can achieve the requirements of the designer, which is very reliable and stable to ensure the dimensional accuracy of the work piece and the forming quality of the flanging. The cold stamping process, common flanging quality problems, due in large part to the workpiece pre pressing not caused, especially in automobile covering parts of flanging, more common. Nitrogen spring appeared to solve this problem. Open up a bright future.
Rolling forming is a kind of material stretching, the formation of local concave or convex, change the shape of blank of cold stamping process, it is mainly used to suppress stiffener, to improve the workpiece stiffness, reducing weight. For some with continuous convex rib parts, due to material extension rate limit, to a rib forming, using nitrogen gas spring can be in a mold, depending on the length of stroke, stepped forming, is very effective to solve this kind of problem, improve pressing productivity. To solve this kind of parts is the main problem can be well positioned, but also makes the parts obtained preform, completely eliminates the material during the forming process, mutual and diversionary effect, effectively ensure the material forming the order, ensuring the quality of parts.
2 Blanking discharging, the top piece and plastic
Blanking is the use of the die to make material is separated into two parts of the cold stamping process, the workpiece or waste from the convex die unloading referred to as unloading, the workpiece or waste material from the die blanking direction along the launch called push piece, against a blanking direction from the concave die ejector called top piece. This is in the blanking process is very common in action. But these three movements do not necessarily exist at the same time. It enhances the punching blade life, proper selection and design of unloading device, to guarantee the quality of blanking parts is very important. The ejector is top, or for intensive punch blanking, often due to the mold space is relatively small, the top piece is relatively large, mold design brings certain difficulty, affect the quality of parts. In some cases, if the unloading stress aggravates the die cutting edge wear. The nitrogen discharge or top, due to its elasticity and pressure big, occupy the mold space is very small, unloading and the top piece and easily reach the equilibrium state, because the stripper plate or top plate can be balanced with nitrogen gas spring contact, cloth force, thus ensuring very smoothly will workpiece ejecting or waste discharge, securing a workpiece straightness, reduce the breaking and the possibility of wear, prolonging the service life of a punch, die design is also very simple, especially for labor-intensive punch stamping parts, more show its advantages. For example engine cylinder pad type parts, using nitrogen gas spring can effectively solve, small space and requirement of mold unloading size paradox. Can even die seat as nitrogen spring chamber to use, reducing the occupying space of nitrogen spring.
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