How to solve the weld marks of injection molding products?

How to solve the weld marks of injection molding products?

In the injection molding process of plastic products, it is found that when the plastic melt fills the cavity, if the front part of the two or more melts have cooled when they meet, so that they can not be fully fused, they will produce grooves at the intersection and form a weld mark.


Causes of welding marks of plastic products:

1, the plastic melt through the gate at high speed directly into the cavity, and then contact the surface of the cavity and cure, and then be pushed by the subsequent plastic melt, thus leaving traces of snakes.

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

3, the use of side gate, plastic after the gate without lag area or lag area is not enough, easy to produce spray marks.


Solutions for welding marks of plastic products:

1. Reduce the number of gates.

2. Adjust the gate position.

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

4. Strengthen the exhaust in the fusion line area to quickly evacuate the air and volatiles in this part. Increase the material temperature and mold temperature, enhance the fluidity of plastics, and improve the material temperature during fusion.

5, change the location of the gate, the number, the location of the fusion line will be moved to another place.

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 agent.

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

10, adjust the gate position, so that the plastic melt through the gate after the impact of the pin or wall.

11, change the form of the gate, using overlapping gate or lug gate, set up enough stagnant area in the gate area.

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

13, increase the gate thickness/cross-sectional area, so that the flow front is formed immediately.

14, increase the mold temperature to prevent the material from curing quickly.