Core laminations causes of burr and preventive measures

Core laminations produce burr, 2019 - the cause and the preventive measures 03 - 30 15:06:10 1, core laminations causes of burr at present, the domestic and foreign large motor iron core laminations are mainly using 0. 5 mm or 0. 35 mm thin electrical silicon steel sheet system. Produced in the process of coining burr big reason, generally speaking is mainly caused by the following reasons. ( 1) Die gap is too big, too small, or uneven. The three conditions of core laminations section has a great impact on the quality and surface quality. From sheet metal blanking deformation process analysis shows that if the clearance between punch and die is too small, punch crack range than the normal clearance near the blade to stagger a distance. Silicon steel sheet in separation, interlayer fault zone will appear burr. Due to the effect of extrusion of the die cutting edge, with the cutting surface to form the second light, the upper extrusion burr or with jagged edges and taper. If the clearance is too large, punch shear crack range than normal clearance near the blade to stagger in a distance. Material is very deep drawing, blunt cutting surface slope increases, so silicon steel sheet is easy to be pulled into the gap, so form elongated burr. In addition, the distribution and also can make plate punching die clearance in local produce larger burr, namely extrusion burr in the big gap in small clearance are produced by spin burr. ( 2) The working parts of die blade dull working parts of die edge rounded corners, due to long-term wear cannot very good material separation effect. At this moment, the whole section for tearing and irregular, it will produce larger burr. Especially in the blanking punch edge and punching die of parts produced during the dull of burr is more serious. ( 3) Equipment for punch precision guide rail, slider and bed the parallelism is not good, the slider movement direction and mesa verticality is bad also prone to burr. Punch accuracy is bad, will cause the centerline of the punch and die the misalignment, produce burr, but also can make the mould guide pillar research. In addition, heavy car happens to the press, there will be a secondary cutting, or punch punching shear force is not enough, also easy to produce very big burr. ( 4) Material reason in actual production, the mechanical properties of silicon steel sheet materials, material factors such as uneven thickness, surface quality is bad, will affect the quality of plate section. Elasticity and plasticity of metal material, the metal stamping performance is determined. Generally speaking, the motor iron core of silicon steel sheet must have certain elasticity and plasticity. Because of motor iron-core pieces only punching and blanking, and trimming and cold stamping process, with good elastic silicon steel sheet material is more appropriate. This is because the elastic good material, high liquid limit, you can get a good cross section quality. 2, the preventive measures for the above, this article analyzes the reasons that the core laminations of burr, in order to reduce the causes of burr, should consider from the following several aspects: ( 1) When processing die, must guarantee the machining precision of convex and concave die and assembly quality, and shall ensure that the vertical and lateral pressure of punch rigidity and the die to also want to have enough rigidity. Qualified mould, punch the normal clearance, for ordinary sheet metal, punching cut section allows the burr height can be seen in table 1. ( 2) When installing a punching die must ensure that the correct convex and concave die clearance value, and on the fixed plate fixed convex and concave die is strong and reliable. Upper and lower template should keep parallel with press working mesa. ( 3) For press good rigidity and elastic deformation is small, high precision guide rail and parallel plate and slide block. ( 4) Press has enough blanking force. ( 5) The use of silicon steel sheet material inspection qualified coining.