Factors affecting the shrinkage rate of metal powder injection molding

With the continuous improvement of metal powder injection molding precision requirements, in addition to the correct material selection and modification, guangdong da-hong new materials think how to choose the right conditions, reasonable analysis of the relationship between shrinkage and production, is very important, especially shrinkage, which seriously affects the quality. The shrinkage rate is mainly affected by many factors. The factors affecting the shrinkage rate of metal powder injection molding by daihong new material can be roughly divided into the following aspects:

1. Resin pressure: it has a great influence on the shrinkage rate of metal powder injection molding. If the resin pressure is large, the shrinkage rate will be small, and the size of MIM material products will be large. Metal powder injection molding manufacturers found that even in the same mold cavity, resin pressure due to the shape of different products and therefore produce shrinkage difference. In the case of multi-cavity mold, the resin pressure in each cavity is easy to produce differences, resulting in the cavity shrinkage is not the same.

2. Mold temperature: whether it is non-crystalline resin or crystalline resin, if the mold temperature is high, the shrinkage rate will increase. Macros new material in precision molding to maintain the mold temperature at a specific temperature. MIM technical experts remind everyone in mold design, should pay attention to the cooling loop design.

3. Gate cross-sectional area: generally speaking, the shrinkage rate changes when the gate cross-sectional area is changed. Shrinkage decreases as the gate size increases, which is related to the fluidity of the resin.

4. Product wall thickness: the product wall thickness also affects the yield. In metal powder injection molding, dahong new material found that for the non-crystalline resin, due to the resin on the wall thickness of the shrinkage rate of different tendency, the wall thickness is large, the shrinkage rate is also large, on the contrary, the shrinkage rate smaller. For the crystalline resin, should avoid the wall thickness change is particularly large. In the case of multicavity die, if the cavity wall thickness is different, the shrinkage rate will also be different.

5, and content of reinforced material, with glass fiber reinforced resin, the more amount of adding glass fiber, shrinkage is small, the flow direction of metal powder injection molding shrinkage rate is smaller than transverse shrinkage rate, big macro new material according to the resin its difference is bigger, in order to prevent distortion fly warp, remind everybody should consider the gate, the gate location and the number of gate shape.

Above that influence several aspects of metal powder injection molding shrinkage factors, small make up big macro new material hope that through this introduction to several factors, can help to you in metal powder injection molding to avoid these problems caused by the shrinkage problem, if you have other questions, welcome to come to consult the big macro new materials technology team!