How to solve flow marks on the surface of ABS injection molded parts

Flow marks on the surface of ABS injection molded parts may be caused by uneven plastic filling, insufficient cooling or mold design. The following are some common causes that may cause flow marks and corresponding solutions summarized by Qingdao prime union:

1.Inappropriate injection temperature: Too low an injection temperature may cause the ABS plastic to be insufficiently melted during the filling process, while too high a temperature may cause excessive viscosity reduction and may also cause flow marks.

Solution: Adjust the temperature setting of the injection molding machine to ensure a suitable plasticizing temperature range. Usually the injection temperature range of ABS is between 200°C and 240°C.

2.Improper mold design: There may be unreasonable gaps, improper nozzle position, poor flow channel design and other problems in the mold design, which affect the uniform filling of plastic.

Solution: Optimize the mold design to ensure smooth flow channels, appropriate nozzle position, and reduce gaps to promote uniform filling of plastic.

3.Nozzle pressure is too high: Excessive nozzle pressure may cause the plastic to generate shear heat during the flow process, making the temperature too high, thus forming flow marks.

Solution: Moderately reduce the nozzle pressure to ensure appropriate injection speed and avoid excessive plastic shear.

4.Insufficient cooling: Insufficient cooling will cause the temperature of the injection molded part to be too high, causing the plastic to enter the next flow area before it is completely solidified, forming flow marks.

Solution: Optimize the cooling system to ensure uniform cooling and increase the cooling time appropriately.

5.The surface of the flow channel is rough: If the surface of the flow channel is rough, it may cause excessive friction in the plastic during the flow process, forming flow marks.

Solution: Optimize the mold manufacturing process to ensure smooth flow channel surface.

6.Nozzle temperature difference: A large temperature difference in the nozzle may cause the plastic to have uneven temperature during the flow process and form flow marks.

Solution: Adjust the nozzle temperature to ensure even heating.When solving the problem of flow marks, the above factors need to be considered comprehensively and investigated one by one. If the problem persists, detailed inspection and optimization with an injection molding professional or moldmaker is recommended.

Qingdao prime union Trading is a plastic raw material distributor integrating industry and trade. It has its own modification factory and a professional after-sales team of injection molding engineers who can assist customers in solving various problems in the sample and production process.