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Mechanical assemblies are composed by components joined through the contact of finished surfaces. The assembly tolerances of these assemblies are obtained from the chain dimensioning of the accumulated tolerances of the respective components. Among the manufacturing processes of metallic parts which allow finished dimensions are mainly the machinin...
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Context 1
... tool wear is illustrated in Fig. 4 (shear angle ). The following parameters characterize the tool wear: 1. Flank (or side) wear determines the length to be considered when punch rework is executed. It is characterized by length L shown in Fig. 4 or by its corresponding side area. The flank wear is created by adhesion and abrasion and increases with the number of strokes. The increasing rate is higher when the clearance is smaller (see Fig. 5(a)). The wear length increases asymptotically to the maximum given by the punch penetration. A semi quantitative assessment is possible by inspecting the flank for scoring and pickup (Shey, 1983). Due to the adhesion of metal layers, the friction force increases progressively and leads the punch side face to produce micro-fractures (Luo, 1997). Flank wear increases the clearance between punch and die and causes the internal diameter of the punched holes to become smaller. When internal diameter of the punched holes becomes too small, the punch reaches the end of its useful ...
Context 2
... tool wear is illustrated in Fig. 4 (shear angle ). The following parameters characterize the tool wear: 1. Flank (or side) wear determines the length to be considered when punch rework is executed. It is characterized by length L shown in Fig. 4 or by its corresponding side area. The flank wear is created by adhesion and abrasion and increases with the number of strokes. The increasing rate is higher when the clearance is smaller (see Fig. 5(a)). The wear length increases asymptotically to the maximum given by the punch penetration. A semi quantitative assessment is possible by inspecting the flank for scoring and pickup (Shey, 1983). Due to the adhesion of metal layers, the friction force increases progressively and leads the punch side face to produce micro-fractures (Luo, 1997). Flank wear increases the clearance between punch and die and causes the internal diameter of the punched holes to become smaller. When internal diameter of the punched holes becomes too small, the punch reaches the end of its useful ...
Context 3
... Edge (or tip) wear is important because it determines the burr height. It is very difficult to differentiate edge wear from flank wear (see Fig. 4). It increases with the number of produced parts and it has a minimum at some fairly generous clearance (Fig. 5(b) shows a curve with 12% ). Excessive clearance (Fig. 5(b) shows a curve with 17% ) leads to a large burr also, but only because the part is finally separated by tensile fracture, and not because of wear. 3. Face wear is mostly abrasive and increases linearly with the number of produced parts (Shey, 1983). It can result from micro-chipping: micro-crushes, fragments and breakage on the cutting edges (Luo, 1997). It is the cause of round and obtuse punch edges. It reduces the punch sharpness during shearing, and increases the deformation of punched workpieces. Burrs become large and the press noise level becomes very high (Luo, ...
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Citations
... Experiments showed significant improvement in wear resistance of tool. Eduardo Umaras et al [10] studied the parameters that effect the dimensional as well as exactitude of the stamping process. The factors which influenced the dimensional of the stamping process are clearance between the punch & die and cutting speed. ...
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