In the process of using injection molding machine to process plastic mold, it is inevitable to produce some unexpected phenomena that damage the quality of products, such as flow mark phenomenon, leaving traces of wire on the surface of plastic mold. Then, what are the causes of plastic mold injection molding products and what are the solutions?
First, plastic mold injection products have flow mark reason
The main reason is the material to produce flow marks do not reach the injection pressure and speed, so that the material flow slow. Influence of mold convection mark:
1, the mold surface temperature is too low, easy to produce flow marks
2. Influence factors of size and number of runner and gate
3, mold exhaust must be sufficient
Two, the influence of molding conditions
1, the tube temperature is too low, melting plastic temperature is also low, the material fluidity is reduced, in the flow direction is easy to form flow mark
2, the material circulation time is not reasonable, the material circulation time is too short will cause melt gum temperature is low, filling material fluidity becomes bad, prone to flow mark.
3, the material in the tube residence time is insufficient, the material temperature will be too low, the material is not easy to fill, the same will form a flow mark.
Three, plastic mold injection molding products have flow mark solution
1, for the injection molding product with large flow length, it is necessary to choose the material with good fluidity, and the suitable proportion of molding lubricant can be added to the material which can not meet the requirement of fluidity, so as to improve the fluidity of the material. The general lubricant content is under 1%, when the flow length of the wall thickness wallpaper is larger, the lubricant content must be increased appropriately.
2, the injection pressure and holding time is insufficient, the condensation of the epidermis is pressed on the die surface, leaving the melt in the flow direction of the flow mark. The method can improve the injection pressure and prolong the holding time, and the condensing layer is tightly pressed on the mold surface until the plastic mold or similar cement product mold is finalized.
3, the injection cycle is too short, the plastic heating temperature is too low to lead to flow mark, can lengthen the injection cycle time, fully make the flow direction traces can not be suitable.
4, the barrel temperature is too low, the melt temperature is low, improve the material temperature, injection pressure and holding time, the condensation layer tightly pressed on the die surface, until the plastic mold stereotypes.
5, the nozzle temperature is too low, leading to the temperature drop, flow mark, improve the nozzle temperature can be higher than the last set of 6 degrees Celsius above.
6, the main channel, diversion channel or gate is too small, resulting in increased flow resistance, can be re examined and gradually increase the size of the casting system.