How to improve weld lines in injection molding?

There are often many new injection molding technologies in the injection molding factory. The reason for the weld line in the injection molding process is that the weld line of the plastic product is caused by the fusion of the molten resin from different directions in the injection process. During the injection process, the two resin streams at the fusion point do not mix with each other; therefore, the lower the temperature, the more obvious the fusion marks and the lower the strength. On the contrary, the higher the temperature, the stronger the adhesion. The state of adhesion at the weld also depends on the pressure applied there. The lower the holding pressure, the poorer the fusion and the lower the strength. The fusion is the confluence point of the resin, and it may also be the end of the flow. In the weld line of the plastic product, if a vent is not well placed at this position to exhaust the gas, the appearance and strength of the fusion will be deteriorated.
Improvements:
l) Increase the resin temperature, increase the mold temperature, increase the injection pressure and speed; heating
2) Pay attention to the exhaust of the parting surface. Adding inserts and thimbles at the place where the weld line occurs is also beneficial to exhaust. 
3) Select a reasonable glue feeding position, and it is best to do a mold flow analysis before opening the plastic product;
4) Increase the process overflow to discharge the cold material, and cut it off after forming. 
5) Thicken and shorten the runner system as much as possible to improve the glue;
6) The rough surface products can be selected as thick as possible, which is also conducive to improving the weld line;