I. status of floating fiber

In the production of glass fiber materials, the simplest appearance is poor, mainly scorched and exposed fiber, and material flowers.

II. Cause analysis of floating fiber:

1. Mold: during glue injection, the activity of material is the activity method of melt. With the introduction of glass fiber, the mobility of glass fiber is much worse than that of plastic. However, the movement of plastic in the mold flows forward from the middle of the interlayer and the two sides turn outward. Therefore, PP with good mobility is in front of the melt, while those with poor mobility will stay on the surface of the mold.

Solution:

A. add glue injection speed to reduce the speed difference caused by viscosity difference. Under the condition of high-speed injection, the relative velocity difference between slow moving glass fiber and fast moving plastic decreased significantly;

B. increase the mold temperature, reduce the touch resistance between glass fiber and mold, and minimize the speed difference between glass fiber and plastic. And let the middle of the plastic be as thick as possible and the shell on both sides be as thin as possible;

C. reduce the measurement temperature, reduce the amount of sol, and minimize the possibility of separation of plastic and glass fiber;

2. Materials: the viscosity of PP, PA and other resins shall be as low as possible within the range permitted by mechanical properties, and the glass fiber shall be as short as possible. If PA66 is used, an appropriate amount of PA6 shall be added to add mobility;

3. Processing technology: A. properly improve the screw shear force; b. Increase the injection speed, and the screw speed can be adjusted to 70%-90%; c. Increase injection pressure; d. The whole screw is retracted by 1-2mm to avoid floating fiber in the gate; e. Graded injection molding is adopted for disordered parts.

4. Additives: it is the most effective way to improve the activity of glass fiber and enhance the bonding ability between glass fiber and resin, such as adding some additives such as silicone and dispersant.

Source: Jiangmen engineering plastics http://m.feimandao.com/