The usual classes of punches and dies may be grouped as follows according to the manner in which they are brought to act upon the material. www.mapeng.net 马棚网机械资讯

Class 1. Blanking shearing and cutting tools. These perform their work by some form of “shearing” of cutting action. They include cut-off and shearing dies, blanking dies, piercing, shaving, notching, edging, and trimming tools. The last are applied to the forming of contour by a series of strokes. For example, a manufacturer uses a punch and die with a concave form which is applied to the cutting of circular disks, in a rapidly operated press which cuts a short are at each stroke, the workpiece being revolved by a step-by-step feeding movement to coincide with the movements of the press slide. The radius of the punch and die cutting edges is laid out to produce the desired circular shape without nicking into the circle as the work proceeds.www.mapeng.net 马棚网机械资讯

Class 2. Drawing dies and similar tools. These tools produce the desired shape of work by drawing the flat piece of metal into tubular or other form under an action that cause the material to “flow” under tension. Under this heading are cupping dies, drawing dies, redrawing dies, reducing dies, and bulging dies.www.mapeng.net 马棚网机械资讯

Class 3. Bending and forming tools. These act upon the workpiece and shape a previously blanked piece by some method of bending, folding, twisting, offsetting, or otherwise reforming a portion or the whole of the blank usually without “drawing” or materially changing the thickness of the metal. In some cases, however, the forming process is closely similar to certain types of drawing operations. The shape of the finished article sometimes necessitates the passing of the blank through an actual drawing process, though this may be for a shallow form only.www.mapeng.net 马棚网机械资讯

Class 4. Embossing, coining, and other heavy pressure dies. Such dies cause a “flow” of the metal under heavy pressure which tend to compress the material into the form desired. Heading, reverting, and staking dies also press the metal into the design established by the shape of the tool faces. Extruding dies act in a corresponding manner in displacing the body of the metal under direct pressure. Coining and embossing operations particularly require heavy pressures in order to force the metal into the design on the face of the tools. The finer lines of relief are brought up clearly only by such pressure, the material displaced by the lower body of the design being thrown up by this “squeezing” action into the higher portions above the original surface of the blank.www.mapeng.net 马棚网机械资讯