In the field of injection molding, Short shot is a common quality problem. Short shot refer to instances when the injected material fails to fill the entire mold cavity, resulting in incomplete or partially formed products. This phenomenon can be attributed to several factors, including insufficient melt temperature, inadequate injection speed, or low-pressure settings. This defect will not only affect the appearance and performance of the product, but also reduce production efficiency and increase costs. Therefore, it is very important to analyze the short-shot problem deeply and take corresponding improvement measures.
1) Nozzle blockage or unreasonable runner design: partial blockage of nozzle will lead to reduced flow rate, which will lead to short shot; If the runner design is too narrow or too long, the melt flow resistance may increase, so that it can not fill the mold cavity fully.
2) Insufficient injection pressure: The injection pressure is not enough to support the melt to overcome the runner resistance, resulting in its inability to evenly fill the mold cavity and cause short shot phenomenon.
3) The barrel temperature is not high enough: insufficient heating of the barrel will make the viscosity of the plastic melt too large, the fluidity is poor, and it is difficult to complete the filling process.
4) Improper mold temperature control: too high mold temperature will make the melt solidify in advance and hinder its flow; On the contrary, the mold temperature is too low, which will lead to weak melt fluidity and is not easy to fill the mold cavity.
1) Check the nozzle regularly: Check and clean the nozzle regularly to ensure that it is unimpeded; At the same time, the runner design is optimized to make it as short and wide as possible to reduce the flow resistance of the melt.
2) Adjust injection molding parameters: Such as increasing injection molding speed, increasing back pressure, etc., to enhance the power of melt flow; In addition, multi-stage injection molding technology can also be used to achieve better filling results under the premise of ensuring product quality.
3) Increase the preheating temperature of the barrel: The plastics are fully melted to reduce the viscosity and improve the fluidity; And by adjusting the temperature of each area, the best processing state is achieved.
4) Control the mold temperature: Choose the appropriate mold temperature according to different materials, and set the cooling system reasonably to maintain the good flow of the melt.
In the face of the problem of short shot in injection molding defects, we need to analyze it from multiple angles and put forward suggestions for improvement. The short shot problem can be improved by adjusting injection molding process parameters, optimizing mold structure and strengthening equipment maintenance.
