What should I do if there is a wind phenomenon during the injection molding process?

During the injection molding process, the phenomenon of wind wrapping is a common and thorny problem, which not only affects the appearance quality of the product, but also may cause damage to the performance of the product. In order to solve this problem, it is necessary to deeply understand its causes, and take effective measures to prevent and deal with it.

In the injection molding process, the plastic raw material is heated to a certain temperature in the barrel and then melted, and subsequently injected into the mold through the push of the screw. If in this process, the molten plastic contains air or moisture, these gases can not escape under high pressure, it will form bubbles or voids in the finished product, the so-called wind phenomenon.

What are the specific manifestations of the wind phenomenon in injection molding? Usually, the wind will lead to the finished product surface depression, silver grain, burn marks and other defects. In serious cases, it may even cause the strength of the product to decrease, affecting its service life.

To deal with the phenomenon of wind wrapping, we can start from the following aspects:

1. material pretreatment: ensure that the plastic pellets used are dry and free of moisture, if necessary, you can use a dehumidification dryer to pre-treat the material and reduce the water content.

2. Equipment Adjustment: Check whether the injection nozzle of the injection molding machine is closely matched with the gate of the mold, so as to avoid air being entrapped in the injection process. Meanwhile, adjust the back pressure valve to increase the back pressure appropriately, which will help the gas in the molten material to be discharged.

3. Mold design: Optimize the design of the exhaust system of the mold to ensure that the gas can be discharged smoothly. Set up exhaust slots or small holes in the areas of the mold that are prone to generating pack wind to help gas discharge.

4. Adjustment of process parameters for injection molding: Adjust the injection speed, pressure and time appropriately to avoid too fast injection speed leading to gas can not be discharged in time. At the same time, control the pressure holding time and pressure holding pressure to ensure that the melt is full of mold cavity.

5. Cylinder temperature control: Reasonably set the temperature of each section of the cylinder to avoid localized overheating or uneven heating, and to reduce the degradation of the material and the generation of gas.

6. Use of degassing equipment: In some special cases, the use of degassing equipment, such as vacuum degasser or ultrasonic degassing device, can be considered to further remove the gas in the molten plastic.

7. Quality control: carry out trial mold and small batch production before the production of injection molding process to check the quality of the product and make sure there is no windbagging phenomenon before proceeding to large-scale production.