1, adhesion and scratching: due to the friction between the material and the punch or the concave die, there is a bad appearance on the surface of the workpiece or mold.
2, burr: mainly occurs in shearing die and blanking die, the burr between the cutting edge or large or hour.
3, line offset: when the workpiece is formed, the first contact with the die is extruded and formed a line.
4, convex concave: there are foreign bodies in the uncoiling line (iron scrap, rubber and dust) mixed into the convex concave.
5, twists and turns: due to uneven stress, poor matching of drawing tendons or bad control of the press slider, twists and strains of the parts of the R or embossed parts of the parts are caused by twists and turns.
6, wrinkles: due to the poor adjustment of the press slide block, low press precision, unsuitable adjustment of air cushion pressure, and big wrinkles in the edge or R parts, such as the punch or the r part.
7. other specific problems: in daily production, the size of punching holes will be large or small (which may exceed the specification requirements) and the size difference between the punch and the punch size. In addition to the design dimensions, machining accuracy and blanking gaps, the following factors should be considered in the following aspects.
8. method to suppress the turnover and distortion of the drawing parts
The reasonable mold design. In progressive die, the layout of blanking sequence may affect the accuracy of drawing parts. In order to reduce the influence of blanking force on the forming of deep drawing parts, a large area of punching cutting material is arranged in general, and a small area of punching and cutting is arranged in the light of the blanking of the fine parts of the drawing parts.
The material is pressed. To overcome the traditional die design structure, the material gap can be opened on the unloading plate, that is, when the mold is closed, the material can be pressed. In the key forming part, the discharge plate must be made into an inlaid structure to facilitate the solution of the grinding (pressure) loss caused by the pressing part of the unloading plate for a long time, and the material can not be pressed.
The additional function of pressure. In order to increase the pressure on the material of the die side, the pressure of the material in the die side is increased by the thickening size (normal unload insert thickness H+0.03mm) in the unloading section.
4. Punch edge end repair inclined or curved. This is an effective way to slow down the blanking force. The cutting force can reduce the tensile force on the side material of the die, so as to restrain the effect of turning and twisting of the drawing part.
The daily mold production, maintenance should pay attention to the punching convex and concave edge sharpness. When the punching edge is worn, the tensile stress of material will increase, so that the tendency of turning and twist will increase.
6. The blanking clearance is not reasonable or not is also drawing gap are stirring and twisted, need to be overcome.
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Post time: Apr-10-2018