Three critical measurements on injection molding processes

The key to implementing control of the injection molding process is to utilize a strategy through which one understands the molding process from a plastics point of view. It is extremely important to understand the plastic as it flows through the barrel of the machine and into the mold, as well as understanding how the various variables of the process acting on the plastic material determine the characteristics of the finished plastic part. To achieve the maximum degree of process control and have positive effects on the finished plastic product being molded, it is important to measure and control these plastics variables. All molding machine settings and environmental factors can be directly or indirectly translated into these plastics variables. Although there are four plastics variables that affect finished plastic product outcome, for purposes of this discussion the author looks at two of these plastics variables plus one lessor variable that relates to finished part quality and productivity. These plastics variables are: plastics melt (stock) temperature; plastics cooling rate; and another related plastics variable: plastics moisture content