外文资料翻译
Stamping and Punching Dies, Compound Die Design北方证券
A 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 asmbly of the lower and upper shoes with guide pins and bushing is a die t. Die ts in many sizes and designs are commercially available.
新疆的大学排名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 lengthwi direction of the sheet or strip. Metal flow takes place within the plastic range of the lengthwi direction of the bend retains a permanent t 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, obtu, 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 Die
Drawing is a process of changing a flat, precut metal blank into a hollow vesl 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 u of mechanical handing equipment.长白山神
种字开头的成语4、Single-action Die
The simplest type of draw dies is one with only a punch and die. One type of drawing die u 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 ud without the stop pin, the more the springs are depresd, the greater the pressure exerted on the blank, thereby limiting the depth of drawing. Becau of limited pressures obtainable, this type of die should be ud with light- gage stock and shallow depths.
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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 indicatealternative ways by which the cavity and core could be incorporated into the mold and we found that the alternatives fell under two main headings, namely the integer method and the inrt method. Another method by which the cavity can be incorporated is by means of split inrts or splits.
When the cavity or core is machined from a large plate or block of steel, or is cast in one piece, and ud 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 becau of characteristics of the strength, smaller size and lower cost. It is not ud as much for multi-impression molds as there are other factors such as alignment which must be taken into consideration.
Of the many manufacturing process available for preparing molds only two are normally ud in this ca. 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 ud to prepare a casting of the cavity or core by or special process.
与春有关的古诗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 machinin g 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 quences and operation would be altogether too complicated and costly. The int-bolster asmbly method is therefore ud instead.
The method consists in machining the impression out of small blocks of银渐层猫咪
steel. The small blocks of steel are known, after machining, as inrts, and the one which forms the male part is termed the core inrt and, converly, the one which forms the female part the cavity inrts. The are then inrted and curely fitted into holes in a substantial block or plate of steel called a bolster. The holes are either sunk part way or are machined right through the bolster plate. In the latter ca there will be a plate fastened behind the bolster and this cures the inrt in position.
Both the integer and the inrt-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 the considerations have already been discusd 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 discusd 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 inrt-bolster design. It should be borne in mind that local inrts can be judiciously ud to simplify the general manufacture of the mold impression.
For multi-impression molds the choice is not so clear-cut. In the majority of cas the inrt-bolster method of construction is ud, the ea 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
摧怎么组词advantageous to u 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 inrt-bolster design which will simplify machining of the plate and allow for adjustments for mold alignment.
