How to deal with the flow mark defect of injection mold molding?

For products with high appearance requirements, such as small home appliance shell, makeup box shell and electronic product shell, the defect of flow mark is a particularly high quality element. Generally speaking, flow mark defect refers to the phenomenon that the flow mark pattern remains on the surface of the product when molding plastic injection molding. The following Xiaobian will be based on the experience of Fanstar from the injection mold, injection molding and molding product design these three dimensions to elaborate the strategy.

In order to deal with convection mark defects, we can start from the following three aspects:

(1) Injection mold coping strategies

1. Increase the surface temperature of the cavity. Within a reasonable temperature range, the higher the surface temperature of the mold cavity, the better the surface quality of the product, and the smaller the internal stress of the product.

2. Enlarge gate size. To enlarge the gate size, it is best to use a round gate and runner section to obtain the best filling.

3. Expand the size of flow channel. Its effect is the same as expanding the gate size, which way is better to choose according to the actual situation.

4. Fully ensure the cold well. Fully ensure that the cold well can effectively prevent the cold material from entering the plastic product molding, so as not to cause bad products.

(2) Injection mold injection molding conditions coping strategies

1. Increase injection pressure. The increased injection pressure helps to overcome the resistance of the flow path, making the molecular chain extend along the direction of the pressure, and the strength of the welding line is improved.

2. Improve the injection speed. Increasing the injection speed can not only shorten the injection time, but also get high quality products at lower mold temperature and shorten the molding cycle.

3. Extend the pressure holding time. Pressure retention is to prevent the product gate in the not completely solidified before the glue flow back and add glue.

4. Increase resin temperature. Melting temperature is too low is not conducive to solving the problem of shrinkage, melting temperature is too high, injection parts are prone to shrink

(3) Design strategies for injection mold forming products

1. Reduce the thickness change of molding products. The molding cycle time increases with the increase of meat thickness, thicker products are prone to warping, and thinner and uniform meat thickness products generally have better appearance quality.

Flow marks are caused by the different cooling degrees between the front part of the resin flow and the surface of the mold during the flow of molten resin in the mold cavity. The MISSION OF FANSTAR IS TO MASTER THE CORE TECHNOLOGY OF injection MOLDING production, communicate and analyze the technology before mold production with customers from the production needs of finished products, so that the mold delivery time is short, the life is long, the rapid mass production and the finished product quality is excellent! There is a need for injection mold open injection molding welcome to contact us!