1、 1 RED CD Blanking is the use of molds to produce separate sheet stamping processes subjects, including blanking and punching. It can be made into parts, but also for the bending, drawing, forming and other processes to prepare rough. Washed down from the Board Division on the shape of the parts req
2、uired (or rough) called off the branches. The shape of the workpiece out of the hole required (red to go to waste) is called punching. Figure I-1 of the washer, from falling branches and punching two processes to complete. Production practice, we die blanking process of a certain understanding of th
3、e structure, but perceptual knowledge to rational knowledge up to truly understand the nature of the blanking process, a better design of the development process and die. The following deformation on the blanking process, the quality of stamping parts, stamping die design and stamping die size blade
4、 structural design issues discussed. . Section blanking deformation mechanism Blanking process Shown in Figure 1-2 blanking by the deformation process can be seen that the composition of the punch and the upper and lower concave edge chess, material on the concave mold, punch the material deformatio
5、n gradually decreased until the completion of all the separate blanking. With the punch of the external forces acting on material changes in the number of the material on the external force changes in quantity, material deformation within the continuous development. The deformation of the blanking p
6、rocess is divided into three stages (Figure 1-2). 1, elastic deformation stage Punch contact with material force as the punch pressure, the material is elastic compression and bending, and squeeze into the die hole. Then the stress does not exceed the material yield limit, if the punch relief, mater
7、ial or restitution, so that elastic deformation stage. 2, plastic deformation 2 Punch to pressure, the stress reaches the yield limit of material, some metal is squeezed into the die hole, producing plastic shear deformation, are shining maggot cut surface. For convex, concave feel there is room bet
8、ween the depression, it is the plastic shear deformation is also accompanied by the bending and stretching. 3, fault isolation stage Materials continue to increase external and internal stress increasing, convex, because the incision die stress concentration, shear strength over the first internal s
9、tress, micro-crack appears. Mold continuing under pressure, convex, concave mold cavities of the micro-crack edge to the material constantly within the share capital, then pulled off material separation. Such as convex, concave die gap was reasonable, the upper and lower crack coincide with each oth
10、er. Stress and strain Further analysis of blanking time of stress and strain state of deformation zone and help to the understanding of the blanking process. Die and punch in the edge of the joint line to take cell body, whose stress-strain diagram shown in Figure 1-3. Can be seen from the figure, i
11、t seems Metal fracture line AB that is cutting edge on-line) at 45 degrees. The main uranium direction I was pulling stress and tensile deformation, tensile stress the gold Is a fiber elongation； its vertical axis 2 is the compression stress direction and compressive deformation, the fiber extrusion
12、 pressure； in the tangential direction of the stress and strain is very small, negligible； and principal stress direction at 45. Direction to the direction of maximum shear stress between the punch and die clearance, elongation and tear off the metal, resulting in broken fracture surface roughness,
13、and with a burr. The process can also blanking blanking force deformation curves of the figure is confirmed. Figure 2-9 (materials), is punching a 3 mm thick material punching power and punch of the curve. Can be seen from the diagram: In the process of blanking blanking force size is constantly cha
14、nging. AB section of the equivalent of punching the elastic deformation stage, BC Section for the plastic deformation stage. When the material internal stress to shear strength began to crack when the material, CD segment for the crack propagation until the material isolated rupture in order teams,
15、DE Dan launch materials introduced die mouth piece. Cut section of See Figure 2-10 The deformation process of blanking the red plant parts are not smooth vertical section, the section has three areas, namely, with rounded corners, bright band and the fault zone. 3 Rounded band is in the process of b
16、lanking the beginning of plastic deformation. Since the bending and stretching metal fibers formed, soft material than hard Branch rounded large. Light zone is the second phase of deformation produced plastic shear deformation of metal forming, has a smooth vertical surface, bright band of the entir
17、e cross section of 1 / 2 to 1 / 3 of the light bandwidth of soft materials, hard materials with a narrow bright . With the mechanical properties of materials, space, mold structural changes. Fault is equivalent to the third stage of the blanking process, mainly due to the role of tensile stress, the
18、 continuous expansion of China cracks down payments second fiber extension, so a very rough surface is not smooth, and there Liaoduo. In the section on the same punch with these characteristics, but the distribution of the three regions opposite position and blanking. Blanking addition to drag a sec
19、tion of rough dimensions, there are points dome curved, not flat, face a burr, so blanking requirements apply only to an Blanking. Section Drawing gap Blanking time requires not only the shape of call times out of line drawing parts, there should be a certain quality requirements, quality of stampin
20、g pieces is cut surface quality, dimensional accuracy and form error. Cut surface should be flat, smooth, no crack and tear, mezzanine and other defects, glitches small parts, the surface should be flat as possible, that is a small vaulted arch, size, degree of precision required to ensure the drawi
21、ngs do not exceed the tolerance range. Factors that affect the quality of stamping pieces range from the actual production that, convex, concave die gap size and power uniformity, pattern edge state, the mold structure and manufacturing precision, quality materials, and so on all affect Na blanking.
22、 However, we must find out which plays a decisive role in the quality of the blanking factor. Gap is a. Section 1 on the quality of blanking Comparison of straight, smooth, and no burr. In this case, the quality of parts that is a good cross section. When the gap is too hours of up and down the crac
23、k does not coincide with each other. . . . When the gap is too large cracks do not overlap. . . . (See 2-11) If the gap uneven distribution of local spikes. . . Uneven wear, increased, so clearance is not only to use reasonable and die on the manufacture and adjustment of space even when the guarantee. 2. Gap on the Dimensional Accuracy Blanking Stamping dimensional accuracy refers to the actual size and nominal size of the margin, the difference is smaller the higher the precision.
