The cause of flow mark in plastic mold
1, Main causes of flow marks
It is caused by the slow flow of materials due to the low injection pressure and injection speed
2, The effect of mould on the flow mark
1. Die surface temperature too low easy to produce flow marks
2. Influence factors of runner and gate size and quantity
3. Mold exhaust must be sufficient
3, The influence of forming conditions mainly includes the following aspects:
1. If the temperature of the material pipe is too low, the temperature of the melt plastic is too low, and the fluidity of the material is reduced, it is easy to form flow marks in the flow direction
2. If the material circulation time is not reasonable and the material circulation time is too short, the melt temperature will be low, and the material fluidity will be poor when filling, and flow marks are easy to appear.
3. The retention time of the material in the material pipe is insufficient, the material temperature will also be too low, the material is not easy to fill, and flow marks will also be formed.
Solution of flow mark in plastic mold injection products
1. For injection molding products with large flow length, materials with good fluidity must be selected. For materials with poor fluidity, appropriate proportion of molding lubricant can be added to improve the fluidity of materials. Generally, the lubricant content is 1%. When the flow length is large for the die wall thickness wallpaper, the lubricant content must be increased properly.
2. Due to insufficient injection pressure and holding time, the condensed skin is pressed tightly on the die surface, leaving a flow mark of the melt in the flow direction. The method can increase the injection pressure and prolong the holding time, and the condensation layer can be pressed tightly on the surface of the mold until the plastic mold or similar cement product mold is finalized.
3. The injection molding cycle is too short, and the low heating temperature of the plastic results in flow marks, which can prolong the injection molding cycle time and make the marks in the flow direction unable to be produced.
4. If the barrel temperature is too low and the melt temperature is too low, increase the material temperature, the injection pressure and holding time will press the condensation layer on the mold surface until the plastic mold is finalized.
5. The temperature of the nozzle is too low, resulting in flow marks caused by material temperature drop. It is enough to raise the temperature of the nozzle, which should be higher than the last set temperature by more than 6 ℃.
6. If the flow resistance increases due to too small main flow channel, diversion channel or gate, the pouring system size can be rechecked and gradually increased. Zhenye injection molding consulting is your most intimate injection molding consultant.
