How to solve welding marks in injection molded products?

During the injection molding process of plastic products, when it is found that plastic melt fills the cavity, if two or more strands of melt have cooled down in the front section when they meet, making it impossible for them to fully fuse, grooves will be formed at the intersection, forming fusion marks.

Reasons for welding marks on plastic products:

1. The plastic melt passing through the gate at high speed enters the mold cavity directly, then contacts the surface of the mold cavity to solidify, and is then pushed by the subsequent plastic melt, leaving traces of snake like motion.

2. When the mold adopts a multi gate feeding scheme, the plastic melt flow front converges with each other; The melt flow front will also be divided into two parts in the pore location and obstacle area; Uneven wall thickness can also lead to weld marks.

3. When using a side gate, plastic passing through the gate is prone to spray marks when there is no stagnant area or insufficient stagnant area.

Solutions for welding marks on plastic products:

1. Reduce the number of gates.

2. Adjust the gate position.

3. Add a material overflow well near the fusion section, move the fusion line to the overflow well, and then cut it off.

4. Strengthen exhaust in the fusion line area to quickly evacuate the air and volatile substances in this area. Raise the material temperature and mold temperature to enhance the fluidity of the plastic and increase the material temperature during fusion.

5. Change the position and number of gates to move the location of the fusion line to another location.

6. Increase the injection speed.

7. Increase the injection pressure and appropriately increase the size of the pouring system.

8. Reduce the use of release agents.

9. Shorten the distance between the gate and the fusion area.

10. Adjust the position of the gate so that the plastic melt collides with the pins or walls after passing through the gate.

11. Change the form of the gate by using overlapping or protruding gates, and set sufficient lagging areas in the gate area.

12. It can slow down the initial injection speed of plastic melt.

13. Increase the gate thickness/cross-sectional area to immediately form a flow front.

14. Raise the mold temperature to prevent rapid solidification of the material.