外文翻譯---沖模及復(fù)合模設(shè)計(jì).docx

外文資料翻譯 Stamping and Punching Dies, Compound Die DesignA compound die performs only cutting operations (usually blanking and piercing) which are completed during a single press stroke. A characteristic of compound dies is the inverted position of the blanking die and blanking punch which also functions as the piercing die. The die is fastened to the upper shoe and the blanking punch having a tapered hole in it and in the lower shoe for slug disposal is mounted on the lower shoe. The guide pins, or posts, are mounted in the lower shoes. The upper shoes contains bushing which slide on the guide pins. The assembly of the lower and upper shoes with guide pins and bushing is a die set. Die sets in many sizes and designs are commercially available.On the upstroke of the press slide, the knock out rod of the press strikes the ejector plate, forcing the ejector tie rod and shedder downward, thus pushing the finished work piece out of the blanking die. Four special shoulder screws (stripper bolts), commercially available, guide the stripper in its travel and retain it against the preload of its springs. The blanking die as well as the punch pad is screwed and doweled to the upper shoe.1、 Bending Die Bending is the uniform straining of material, usually flat sheet or strip metal, around a straight axis which lies in the neutral plane and normal to the lengthwise direction of the sheet or strip. Metal flow takes place within the plastic range of the lengthwise direction of the bend retains a permanent set after removal of the applied stress. The inner surface of a bend is in compression; the outer surface is in tension. A pure bending action does not reproduce the exact shape of the punch and die in the metal; such a reproduction is one of forming. The neutral axis is the plane area in bend metal where all strain is zero.2、 Bending Methods Metal sheet or strip, supported by a V bending, produces a bend having an included angle which may be acute, obtuse, or of 90. Friction between a spring-loaded knurled pin in the Vee of a die and the part will prevent or reduce side creep of the part during its bending. Other methods are Z-bending edge bending and U-bending etc.3、 Drawing DieDrawing is a process of changing a flat, precut metal blank into a hollow vessel without excessive wrinkling, thinning, or fracturing. The various forms produced may be cylindrical or box-shaped with straight or tapered sides or sides or a combination of straight, tapered, or curved sides. The size of the parts may vary from 0.25mm diameter or smaller, to aircraft or automotive parts large enough to require the use of mechanical handing equipment.4、 Single-action Die The simplest type of draw dies is one with only a punch and die. One type of drawing die use in a single-action press is shown in Fig.3-4. This die is plain single-action type where the punch pushes the metal blank into the die, using a spring-loaded pressure pad to control the metal flow. The punch has an air vent to eliminate suction which would hold the cup on the punch and damage the cup when it is stripped from the punch by the pressure pad. The sketch shows the pressure pad fitting the stop pin, which acts as a spacer that an even and proper pressure is exerted on the blank at all times. If the spring pressure pad is used without the stop pin, the more the springs are depressed, the greater the pressure exerted on the blank, thereby limiting the depth of drawing. Because of limited pressures obtainable, this type of die should be used with light- gage stock and shallow depths. Mold Cavities and Cores The cavity and core give the molding its external shapes respectively, the impression imparting the whole of the form to the molding. When then proceeded to indicate alternative ways by which the cavity and core could be incorporated into the mold and we found that these alternatives fell under two main headings, namely the integer method and the insert method. Another method by which the cavity can be incorporated is by means of split inserts or splits.When the cavity or core is machined from a large plate or block of steel, or is cast in one piece, and used without bolstering as one of the mold plates, it is termed an integer cavity plate or integer core plate. This design is preferred for single-impression molds because of characteristics of the strength, smaller size and lower cost. It is not used as much for multi-impression molds as there are other factors such as alignment which must be taken into consideration.Of the many manufacturing processes available for preparing molds only two are normally used in this case. There are a direct machining operation on a rough steel forging or blank using the conventional machine tool, or the precision investment casting technique in which a master pattern is made of the cavity and core. The pattern is then used to prepare a casting of the cavity or core by or special process. A 4.25% nickel-chrome-molybdenum steel (BS 970-835 M30) is normally specified for integer mold plates which are to be made by the direct machining method.The precision investment casting method usually utilizes a high-chrome steel. For molds containing intricate impressions, and for multi-impression molds, it is not satisfactory to attempt to machine the cavity and core plates from single blocks of steel as with integer molds. The machining sequences and operation would be altogether too complicated and costly. The inset-bolster assembly method is therefore used instead.The method consists in machining the impression out of small blocks of steel. These small blocks of steel are known, after machining, as inserts, and the one which forms the male part is termed the core insert and, conversely, the one which forms the female part the cavity inserts. These are then inserted and securely fitted into holes in a substantial block or plate of steel called a bolster. These holes are either sunk part way or are machined right through the bolster plate. In the latter case there will be a plate fastened behind the bolster and this secures the insert in position.Both the integer and the insert-bolster methods have their advantages depending upon the size, the shape of the molding, the complexity of the mold, whether the single impression or a multi-impression mold is desire, the cost of making the mold, etc. It can therefore be said that in general, once the characteristics of the mold required to do a particular job which have been weighed up, the decision as to which design to adopt can be made.Some of these considerations have already been discussed under various broad headings, such as cost, but to enable the reader to weigh them up more easily, when faced with a particular problem, the comparison of the relative advantages of each system is discussed under a number of headings.Unquestionably, for single impression molds integer design is to be preferred irrespective of whether the component form is a simple or a complex one. The resulting mold will be stronger, smaller, less costly, and generally incorporate a less elaborate cooling system than the insert-bolster design. It should be borne in mind that local inserts can be judiciously used to simplify the general manufacture of the mold impression.For multi-impression molds the choice is not so clear-cut. In the majority of cases the insert-bolster method of construction is used, the ease of manufacture, mold alignment, and resulting lower mold costs being he overriding factors affecting the choice. For components of very simple form it is often advantageous to use one design for one of the mold plate and the alternative design for the other. For example, consider a multi-impression mold for a box-type component. The cavity plate could be of the integer design to gain the advantages of strength, thereby allowing a smaller mold plate, while the core plate could be of insert-bolster design which will simplify machining of the plate and allow for adjustments for mold alignment. 沖模及復(fù)合模設(shè)計(jì)復(fù)合模是指在一次沖壓行程中完成幾道沖裁工序（通常包括落料和沖孔）的模具。復(fù)合模的特點(diǎn)是能夠調(diào)轉(zhuǎn)落料模和沖孔模（凸模和凹模）的位置，即落料模也可以作為沖孔模。沖頭和內(nèi)部帶有錐孔的落料凹模被固定在上模座板上，下模座板上開有推桿放置孔。導(dǎo)料銷或?qū)е惭b在下模座上，導(dǎo)套安裝在上模座上且可以沿導(dǎo)柱滑動(dòng)。上、下模座（帶有導(dǎo)柱和導(dǎo)套）組合成模架。模架在市場上可以買到，且有多種尺寸和結(jié)構(gòu)供選擇。 在沖壓機(jī)滑塊的向上行程中，沖壓機(jī)的打料桿接觸到推件板，作用在連接推桿上的力使卸料裝置下移，將沖壓件從落料凹模中推出。四個(gè)特殊的帶肩螺釘（卸料螺釘，在市場上可以買到）引導(dǎo)卸料裝置移動(dòng)，并使其抵抗彈簧的預(yù)壓。與沖孔凹模一樣，落料凹模也用螺栓和銷釘安裝在上模座上。1、 彎曲模彎曲是指材料（通常是板料或條料）圍繞位于中性面上縱向的直線軸產(chǎn)生均勻變形的沖壓工藝。因?yàn)閺澢鷷r(shí)金屬流動(dòng)發(fā)生在金屬塑性變形范圍內(nèi)，所以去除施加的外力后，彎曲將保持永久的變形。彎曲件的內(nèi)表面處于壓縮狀態(tài)，外表面處于拉伸狀態(tài)。單一的彎曲工序并不能使金屬材料呈現(xiàn)出與模具的凹模或凸模完全一致的狀態(tài)，這種復(fù)制工藝也是一種成型方法。在受到彎曲作用的金屬中，中性面是彎曲金屬上張力為零的平面區(qū)域。2、 彎曲方式 放置在V 形支撐塊中的板料或條料在楔形沖頭的作用下壓入V形凹模，這類彎曲方式稱為V形彎曲。V形彎曲能夠生產(chǎn)帶有鈍角、銳角或直角的彎曲件。V形模具內(nèi)的彈簧加載壓銷和零件之間的摩擦力將組織或減少彎曲時(shí)邊緣的移動(dòng)。其他彎曲方式有Z形彎曲、側(cè)邊彎曲和U形彎曲等。3、 拉深模拉深是把一定形狀的金屬平板制成空心零件而不發(fā)生起皺、變薄或開裂現(xiàn)象的沖壓工序。不同形狀的拉深可得到不同圓柱形或盒形制件，這些側(cè)壁的形式有直壁、錐形壁、直壁和錐形壁混合的側(cè)壁以及曲面壁。拉深件的尺寸相差很大，從直徑為0.25mm或更小的拉深件，到足以覆蓋機(jī)械設(shè)備的航天器或汽車覆蓋件。4、 單次拉深模最簡單的拉深模指帶有一對(duì)凹模和凸模，這種結(jié)構(gòu)是簡單的單動(dòng)沖壓類型，沖頭把金屬胚料壓入凹模，利用彈壓板控制金屬流動(dòng)。沖頭上開設(shè)的排氣孔能夠消除推出拉深件時(shí)產(chǎn)生的真空吸力，這種真空現(xiàn)象能使杯形拉深件包緊在沖頭上，若有壓料板強(qiáng)制脫模，則會(huì)損壞杯形件。模具裝有壓料板，壓料板起壓料作用沖壓時(shí)能為沖頭外的胚料提供均勻而合適的壓力。如果彈簧板沒有安全墊圈，那么彈簧壓縮量越多，板料承受的壓力就越大，這將限制拉深的程度。由于有效的壓力有限，故這種拉深模使用于所需沖壓力較小及深度較淺的沖壓件。 型腔和型芯 模具的型腔和型芯分別形成塑件內(nèi)部和外部形狀，型腔形狀決定了塑件外部形狀，接下來我們簡要說明選擇哪種方式把型腔和型芯安裝在模具中，這些方式可歸納為兩大類，即整體式和鑲拼式。另一種組成型腔的方式是加入拼塊或滑塊。當(dāng)型腔或型芯由一塊大的鋼板或剛塊加工而成，或者鑄成一體，不需使用支承板件而形成一塊模板時(shí)，就構(gòu)成整體式型腔板