Author: MULAN -Plastic Molding Manufacturer
What are the reasons for welding marks in injection molds? As an excellent mold manufacturer, Xingye Plastic Mold Factory will introduce the reasons for welding marks in injection molds: Welding marks are caused by the cooling of the front part of the molten resin from different directions. produced. Not fully fused at the junction. Fusion occurs at resin junctions.
The two streams of resin fuse when they meet. The editor of Xingye Plastic Mold Factory tells you that the lower the temperature, the more obvious the fusion. Since the two streams of resin at the fusion do not mix with each other (because they advance while solidifying during the injection process), if the temperature is lower, the surface will thicken, the lines will be obvious, and the strength will be reduced.
This is because the bond between the two is weakened. Conversely, if the temperature of the two resin streams is higher, the adhesion will be enhanced and the appearance will be less obvious. The two molten resins are extruded at the fusion, where the bonding state depends on the pressure applied here.
The lower the holding pressure, the more obvious the fusion and the lower the strength. If not only the holding pressure setting is to be considered, but also the actual pressure applied at the fusion will reduce this condition. This is because pressure transfer becomes more difficult as curing progresses.
In addition, if the gate size becomes smaller, the gate position becomes worse, and the appearance and strength of the fusion deteriorate. The fusion is the confluence point of the resin, and it may also be the end of the stream. At this time, if a vent is not provided at this position to discharge the gas, the appearance and strength of the fusion will deteriorate.
In general, it mainly affects the appearance, coating and electroplating. In severe cases, it will affect the product strength (especially when fiber reinforced resin). Regarding the improvement idea, the plastic mold factory introduces as follows: 1. Adjust the molding conditions to improve the fluidity.
For example, increase resin temperature, increase mold temperature, increase injection pressure and speed. 2. Adding exhaust slots and setting push rods where welding traces are produced is also conducive to exhausting. 3. Minimize the use of release agents.
4. Set the process overflow as the place where the weld line is generated, and cut it off after forming. 5. According to the plastic mold factory, if it only affects the appearance, you can change the four burning positions and change the position of the weld line. Or treat the part where the weld line occurs into a dark glossy surface for modification.
For more information about plastic molds, please visit Xingye's official website: http://www.dgxingyesj.com/.