Well, this is an important technique that could help injection molders to improve molding process within a few minutes. The technique could be summarized briefly with a few words “first fast and then slow shoot”,i.e, first rate injection speed until the fill is complete on the preset position and then use second rate slower shoot which usually starts at the end of fill. Rapid injection speed helps to maintain the temperature of the molten plastic and overcome the resistance from mould cavity, which gets the plastic fill completed smoothly. On the other hand, the slower shoot is a good way to vent the trapped air, preventing flash and shrinkage problems. Skilled Application of this technique can also help to trouble shoot many difficult molding problems . 1.It can be used to solve the trouble of trapped air in injection molded parts,including air stuck in “dead corners” 2.It is used to solve thecontradictionary issues occuring on the same mold such as flash and shrinkage caused by the imbalance of the water in each cavity of the mold 3.It can also be used to solve problems such as flash, whitening or shrinking. 4.Can also be used to solve the problem of filling difficulties. Therefore, this molding technique is one of the key techniques that we must learn to master and be able to use flexibly. Of course, during the production process, injection molders could also intersperse with a few more injection stages to the principle of of “first fast and then slow shoot” based on the on-site situation to solve other injection issues. For example, you could start with slower shoot speed stage to solve the air mark around injection gate, which is higher level of application of this technique. For more technical support on how to use the technique in complicated multi-stage injection process, please contact HSMOLD!