Best discusses the factors that affect the metal injection molding process are these reasonstime：2020-05-08Views：151 Author：Best Seiko
Metal injection molding process (abbreviated as MIM) is a method of mixing metal powder and organic binder into granules, and then manufacturing them into specific traits by injection molding, especially suitable for small, complex and precision metals The manufacture of parts has also been recognized and used by quite a number of precision parts manufacturers, and occupies an important position in the field of metal product forming today. This process requires the preparation of the injection material in advance, which is often referred to as MIM feed, and has relatively strict requirements on the rheology of the feed. The two injection feeds currently in common use by MIM are iron-based feeds (such as Fe2Ni, Fe8Ni) and stainless steel feeds (such as SUS316L, SUS630 17-4, SUS304, etc.). With the recent demand for stainless steel products The larger, the research on stainless steel feeding is also rapidly heating up. Feeding is the first step of the process, so the characteristics of the feed directly affect the parameters of all subsequent processes and the quality characteristics of the finished product. Today, Best is taking the commonly used stainless steel as an example. Let's take a look at the three major factors that affect the flowability of stainless steel feed in the production process parameters. First, the powder loading capacity. The powder loading is a ratio, which refers to the percentage of the powder volume to the total volume of the feed. The larger the powder loading, the greater the proportion of powder in the feed. At this time, the viscosity of the feed increases, and the rheology becomes correspondingly worse; when the powder loading becomes smaller, the proportion of the binder increases accordingly. When the feed viscosity decreases, the fluidity improves. But it's not that the more binders, the better. The influence of the amount of binder on other subsequent processes must also be considered. Second, the shear rate. In the injection molding process, the stainless steel feed flows at a high shear rate, so the feed is heated by high shear force, and the viscosity decreases after the heat is generated, so the fluidity is strong; otherwise, when the feed is at a low shear rate Flow, the heat generated by the lower shear force is slower, the viscosity will not be significantly reduced, and the fluidity is relatively poor. Third, temperature. Here mainly refers to the injection temperature during injection molding and the temperature after entering the cavity. The effect of temperature is a thermally activated process for stainless steel feed. The temperature affects the fluidity of the feed viscosity. When the temperature increases, the viscosity of the feed will become smaller and the corresponding fluidity will become stronger. When the temperature is lowered, the feed viscosity becomes larger and the fluidity will be worse. The above are the three main factors that affect the flowability of stainless steel feed. In general, the influence of various factors on stainless steel feeding will follow the above rules, but there are many factors that affect the fluidity of stainless steel, and the changes reflected in different production conditions are not the same, so each stainless steel product manufacturer When purchasing and using stainless steel feed, comprehensive consideration should be given to adjust the working environment to a very good state according to the actual situation.