How to solve the Die Casting Shrinkage problem
Die Casting exist shrinkage problem is a common phenomenon, there is no method to solve this problem? Answer should be yes, but it will be what is it? A die-casting shrinkage cavities and the reason for the existence of loose phenomenon: Die Casting pieces of shrinkage cavities are bound to exist in only one loose phenomenon that is due to the metal melt filling the liquid into a solid phase contraction phase transition. die casting solidification characteristics is cooled from the outside when when casting wall thickness, internal inevitably produce Shrinkage problems. So, die castings, especially for Heavy die-casting parts, the existence of shrinkage shrinkage problem is inevitable, is not a solution. 2, the only way to solve Die Casting Shrinkage defects: Die Casting Shrinkage can not be completely resolved from the die casting process itself, to solve this problem, only to go beyond the process, or is sought from outside the system solution. This approach? Solve the casting Shrinkage defects from the process principle, only in accordance with the ideology of the feeding process. Contraction of the casting solidification process of phase change is a natural physical phenomenon, we can not reverse the laws of this natural phenomenon, but only to follow its rules to solve this problem. 3, the feeding of two ways: the casting of feeding, there are two ways, one natural feeding, first, mandatory feeding. To achieve a natural feeding, the casting process, it is necessary to achieve the solidification process measures. Many people intuitively think that, using low pressure casting method to be able to solve the shrinkage of the casting shrinkage defects, but the fact is not so. the use of low pressure casting process, does not mean that you can solve the casting Shrinkage defects, if the low pressure casting system is not equipped with the feeding process measures, then this means of low pressure die casting production out of the rough is also possible that one hundred percent Shrinkage defects. Due to the characteristics of the die casting process itself, to set up the natural "order of solidification process measures is difficult, but also more complex. The most fundamental reason may also be the" solidification "process measures, the general requirements of casting a relatively long coagulation time, and die-casting process itself is a bit contradictory. ; Forced solidification feeding characteristics of the coagulation time is short, generally and "solidification" quarter or less, so on the basis of the die casting process, the addition of forced feeding process measures is with die-casting process characteristics suited to a good solution to the die casting Shrinkage problems. Forced feeding two levels: Squeeze feeding and forging feeding: forced feeding of casting can be achieved with two levels. A basic casting shrinkage can be eliminated to the extent of shrinkage defects, one can make rough internal to achieve the degree of crushing grain or forging state organizations. If you want a different word to describe these two different degrees, then the former we can "squeeze feeding" to express the latter, we can use the "forging feeding to express. Give full attention to an understanding, to distinguish between a concept are a direct means of feeding, it can not be done indirectly. Technology process parameters to express this is to "fill the shrinkage pressure. Physical principles, the concept of pressure both cases, there may be a liquid occasions, that the occasion of the "Pascal's law, in order to distinguish, we define it as" liquid pressure ", while another in the solid state occasions , we define it as "solid-state pressure. It should be noted that the pressure application of the concept of two different state conditions. If we are confused, there will be a big |
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