The physical cause of the melting seam is the place where the melting seam is formed as the fine stream fork of the melt and connecting it together. The most typical is the melting flow around the core or the use of pouring ports.
In the place where the stream meets again, the surface will form a fuse and flow line. The larger the core of the melt, the longer the flow road between the mouths, the more obvious the felting seam formed. Small melting seams will not affect the strength of the product.
However, where the process is very long or inadequate, the dissatisfaction of the charging mold will cause obvious grooves. The main reason is that the fluid front end is uniformly fused to produce a weak light point. The place where the pigment is added to the polymer may produce spots, because there are obvious differences in the orientation. The number and location of the portal determine the number and location of the melting seam. The smaller the angle when the fluid striker meets, the more obvious the melting seam.
In most cases, process debugging cannot completely avoid melting seams or material flow lines. What can be achieved is to reduce its brightness, or move them to unique or completely invisible places.
Therefore, the specific analysis should be analyzed for specific issues. The reasons and improvement measures related to the processing parameters are: the injection speed is too low to increase the injection speed; The surface temperature is too low to increase the temperature of the mold; the pressure preservation is too low, increase the pressure preservation, and perform pressure to switch as soon as possible.
The reasons and improvement measures related to design are: the location of the mouth is unreasonable, re -position the pouring and move it to the invisible place; The size of the pores should meet the characteristics of the material.