Several Factors Affecting Plastic Injection Molding Processes (Part one)

Abstract: The injection molding process plays an important role in the plastic molding process, which determines the quality, shape, and appearance of plastic products. The most important thing is that the plastic injection molding process has a great impact on the performance of the product. To better guarantee the quality of products produced by injection molding, the factors that affect the plastic injection molding process are analyzed in this article.
 
Plastic injection molding has the characteristics of convenient operation, high precision, good quality and wide applications. It is a common molding for forming plastic products. The quality of products produced by injection molding is much higher than that of blow molding and over-compression molding. Injection molding needs to go through 8 stages such as feeding and melting. It is meaningful to study the factors influencing the plastic injection molding process due to the many advantages of injection molding. By optimizing the plastic injection molding process, the quality of plastic products can be improved. To improve the quality of plastic injection molding products, it is necessary to analyze the factors affecting the process in the injection molding process such as temperature, time, pressure, shrinkage, fluidity, crystallinity, stress cracking and melt fracture, etc.
 
1. Influencing factors of the plastic injection molding process
Influence of pressure during injection molding
Pressure is a very important influencing factor in the injection molding process. The pressure types involved in plastic injection molding mainly include pressure maintaining, injection pressure and plasticizing pressure. The analysis of these three pressures is described below.
 
1) Analyzing the influence of pressure maintaining
In order to prevent the resin from reflowing in the cooling process, it is necessary to apply a holding pressure on the resin. The purpose is to reduce the shrinkage rate of the resin in the cooling process, increase the pressure maintaining and make the resin melt fully filled in the mold, so that plastic parts with better product quality can be made. However, when the pressure maintaining is too high, it will be difficult to demould. Therefore, in the actual production operation process, the holding pressure should be set according to the specific process.
2) Analyzing the influence of injection pressure
The purpose of increasing the injection pressure is to improve the speed of the fluid die, improve the fluidity of the melt and reduce the shrinkage rate in the molding process of the resin. Injection pressure is an important parameter in plastic injection molding. The pressure and pressure maintaining time are directly related to the performance of the product and affect the quality of the final plastic part.
3) Analyzing the effect of plasticizing pressure
Increasing the plasticizing pressure will increase the temperature of the melt, thereby reducing the plasticizing speed. Increasing the plasticizing pressure can also make the melt temperature more uniform, and increasing the plasticizing pressure can improve the structural properties of plastic products.