Tungsten Copper Powder Injection Molding Research (2/2)

Many parameters of injection molding should be perfectly controlled, such as the temperature, the pressure, the speed and so on. Theoretically, in the process of injection molding, the temperature and pressure are the largest influencing factors of molding properties. In order to press tungsten copper powder mixture into the mold cavity, the temperature inside the injection machine must be high enough so that moderate viscosity mixing, the two-phase does not separate. For injection pressure (to overcome the flow mixing cavity flow resistance, provide filling speed and compaction of the melt) and speed in the experiment demonstrated that there is an optimal match range, pressure and speed should not be too large or too small. The following is the impact of temperature and injection table corresponding to the formation of body performance and injection molding pressure and injection speed of the blank:

From the figure above, we can also find the optimum temperature range for injection, injection pressure and speed. Since the injection process to fill the cavity is more complex, many parameters must be well controlled, once appear unreasonable control can cause a variety of defects. We introduce some common defects and the corresponding solutions: 1. Under-injection, it refers to the injection process feed can not fill the mold cavity, the corresponding solution is three-pronged approach from the injection temperature, feeding quantity and viscosity of the feed itself causes analyzed; 2. The pores, it is the most common type of defect, the corresponding method is to pay attention to whether the injection and mixing of air entrainment and make adjustments, check the injection speed, the injection pressure, etc; 3. Unstable quality, it should be considered that whether the powder is uniform and the segregation with the binder.