Analysis of the cause: When the mold adopts the multi-gate pouring scheme, the rubber flow fronts meet each other; the hole position and the obstacle area, the rubber flow front will be divided into two; the wall thickness unevenness will also lead to the weld mark. . The high-speed plastic melt passing through the gate directly enters the cavity and then solidifies upon contact with the surface of the cavity, which is then pushed by the subsequent plastic melt to leave traces of the snake. Side gates, when the plastic passes through the gate without a stagnant area or the stagnant area is insufficient, it is easy to produce spray marks.
Countermeasure: Reduce the number of gates. A material overflow well is added near the fusion zone, the fusion line is moved to the overflow well, and then it is removed. Adjust the gate position. Change the position and number of gates and move the position where the fusion line occurs to other places. Strengthen the exhaust in the fusion line area, quickly evacuate this part of the air and volatiles. Increase the material temperature and mold temperature, enhance the fluidity of the plastic, and improve the material temperature during the fusion. Increase the injection pressure and increase the size of the casting system. Increase the injection speed. Shorten the distance between the gate and the weld area. Shorten the distance between the gate and the weld area. Reduce the use of release agents. Adjust the gate position so that the plastic melt passes through the gate and collides with the pin or wall. To change the gate form, use overlapping gates or lug gates to set up enough stagnant areas in the gate area. It can slow down the initial injection speed of the plastic melt. Increasing the gate thickness/cross-sectional area allows the flow front to form immediately. Increase the mold temperature to prevent rapid solidification of the material.