【正文】 ve. Can be seen from the diagram: In the process of blanking blanking force size is constantly changing. 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, DE Dan launch materials introduced die mouth piece. Cut section of See Figure 210 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 blanking 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 entire 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 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 section 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 stamping 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 drawings 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. 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 crack does not coincide with each other. . . . When the gap is too large cracks do not overlap. . . . (See 211) 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. 4 difference between living in two areas packet error, one blanking punch or die with the size of the deviation, one mold itself create bias. Blanking and convex, die size deviation was mainly due to: Workpiece (waste) from the concave mold release, as caused by elastic recovery. Deviation may be positive, it could be negative. Factors affecting the value of this deviation are: 1, convex, concave mold gap. Big gap. . . Tensile obvious effect, elastic recovery materials and parts to drop less than the die size, punching pieces. . Small gap. . . 2, material properties. Material properties and dimensional accuracy of packages since it will then determine the material properties of its material form in the amount of blanking. Outline of the elastic deformation of the soft small amount of elastic recovery after blanking also small, so the workpiece accuracy. Hard steel elastic recovery greater precision on the lower parts. 3, workpiece shape and size. Workpiece thickness and shape of post degree onlyJ also have an impact, thin elastic recovery of material punching shield large,t pieces of low accuracy. The more plex the shape of the workpiece, die and create and adjust the gap when the more difficult to ensure uniform, so the greater the size of deviations. See Figure 213 4. Bladelike quality video straight to the section noon 5. Gap on the impact of blanking force The smaller the gap, blanking deformation area of the higher hydrostatic pressure, the greater the material change Kang force. Blanking force, the greater the contrary, when the gap increases, lower resistance, blanking force also 5 decreases, but the value is not reduced (see Figure 214) Life on the sidelines of the impact of mold (see materials abbreviated talk) Section III to determine clearance punch and die Thus, convex and concave clearance on blanking die quality morning, punching power, tool life has a great impact, so the mold design will select a reasonable gap to ensure Blanking section of good quality punching required is small, highdie life. But the difference of quality, precision, blanking force requirements in many aspects of cooperation were identified gap is not limited to the same a value, but close to each other, taking into account the deviation of model county manufacturing and use of wear and tear, Therefore, production is