Die Die Die Die Failure And Maintenance

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Improve die Mold Service Life of



Casting mold as long production cycle, large investment and manufacturing of high precision, it is high cost, so we have a higher mold life. However, materials, machining and a series of internal and external factors, leading to premature failure and die scrap, resulting in tremendous waste.



Failure of die casting mold forms are: sharp corners, corner cracking, splitting, thermal cracking (cracking), wear, erosion and so on. Caused major causes of failure of die casting mold: Material own shortcomings, processing, use, maintenance, and heat treatment of the problem.



One's own material defects



Is well known that the use of die casting mold extremely harsh conditions. With aluminum die-casting mold, for example, the melting point of aluminum 580-740 , use, temperature control of molten aluminum in the 650-720 . Preheating in the case of not casting mold, cavity surface temperature rose from room temperature direct liquid temperature, the cavity surface of the enormous tensile stress. Top mold piece, the cavity surface of the enormous stress. Thousands of die-casting, the mold surface can lead to cracking and other defects.



Thus, die-casting conditions of use are acute thermal quench. Die Materials Should use thermal fatigue resistance, fracture toughness, thermal stability, high hot work die steel. H13 (4Cr5MoV1Si) is applied over a wide range of material, It is reported that of 80% of the cavity are used H13, is still a large number of domestic use 3Cr2W8V, but 3Cr2W8VT_ Arts performance is not good, poor thermal conductivity, linear expansion coefficient is high, work have a great thermal stress, resulting in cracks or even break mold, and heating trade decarbonization to reduce die wear resistance, so are out of steel. Maraging steel applied to heat cracking and wear resistance and corrosion resistance of less demanding on the mold. Heat-resistant alloy of tungsten and molybdenum is limited to more severe thermal cracking and corrosion of small inserts, although the alloy is brittle another notch sensitivity, but the advantage of good thermal conductivity, but can not be set on the need for cooling of the thick channel die casting die casting mold has a good adaptability. Therefore, reasonable under the heat treatment and production management, H13 still has satisfactory performance.



Manufacture die casting mold material, regardless of where one should be consistent with design requirements, ensure the casting mold in their normal conditions of use to meet the design service life. Therefore, production before the material a series of checks should prevent the material with defects, resulting in mold costs of early retirement and processing waste. Corrosion inspection tools are commonly used in macro-examination, metallographic examination, ultrasound examination.



(1) macro-corrosion inspection. Mainly the porous material, segregation, cracking, cracks, and crack the surface of the hammer, joints.



(2) metallographic examination. Mainly the grain boundary carbide material segregation, distribution, grain and grain between the inclusions Liaoduo.



(3) ultrasound. Mainly the defects inside the material and size.



2, die casting mold processing, use, repair and maintenance



Mold design manual has been described in detail in design of die casting mold problems, but in determining the injection speed, the maximum speed should not exceed 100m / S. Speed is too high to promote corrosion and mold cavity and core the sediment increased; but easy to make low casting defects. So for magnesium, aluminum, zinc and the corresponding most low injection speed 27,18,12 m / s, the maximum injection speed of aluminum should not exceed 53m / s, the average injection speed 43m / s.



During processing, thicker template superposition method can not guarantee its thickness. 1 times as thick steel plate, bending deformation is reduced by 85%, stacking can only play a role in stacking. Veneer thickness and the same two plates in bending deformation is 4 times the veneer. Also in the process cooling water, the two sides should pay particular attention to ensure processing concentricity. If you head around the corner, not concentric with each other, then use the process, the connection will be cracking around the corner. The surface of the cooling system should be smooth, preferably machined without leaving traces.
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Die Die Die Die Failure And Maintenance

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This article was published on 2010/10/20