Table of Contents
What is injection rate in injection molding?
Injection rate refers to the volume flow rate that can be achieved per unit time at the time of injection, such as the ratio of injection capacity and injection time.
What is injection time in injection molding?
The injection time is the time it takes for the mold to fill completely. When you set up a Fill+Pack analysis sequence, the software can be set to either calculate a machine injection time automatically, or on the basis of a user-specified value. By default, the injection time is calculated automatically.
What is injection velocity?
The injection velocity is the speed at which polymer is injected into the mold cavity during the injection phase. If the injection velocity is too high, it can cause part defects such as flash and delamination.
How do you calculate injection pressure in injection molding?
A general calculation for determining press size needed is as follows: Pressure (lb/in2) x Projected Area (in2) = Force (lb.) Here are a few other important tips for calculating the right press size for your plastic injection molded part.
What is unit of injection speed?
The performance of an injecting unit is expressed by the injection rate (the volume of molten plastic that is injected in one second, cm3/s) or the injection speed (the speed of forward movement of the plunger, mm/s).
What is screw speed in injection molding?
The screw rotation speed in plastic injection molding is the speed of rotations of the screw for mixing the pellets. Its unit is rpm (revolutions per minute). If the screw rotation speed is too high, air gets mixed inside the molten plastic which can make gas generation to occur easily.
What is VP in injection molding?
Solution: The V/P switch-over indicates the point – usually a percentage of the total volume – where the injection molding machine (IMM) will change the filling process from a velocity driven (fill) to a pressure driven control (pack).
How do you calculate shot capacity?
To calculate the injection stroke or shot size, we can put all values in the formula of shot volume, i.e., Shot Volume = π x r2 x Shot Size. Here, r=1.4 and shot volume is 26.71 cm^3.
What is screw diameter in injection molding?
The screw diameter is important for 2 reasons. The first reason is that it determines the maximum available injection pressure, the smaller the diameter the higher the available pressure. This is critical for parts that have thin walls and a long flow length and for plastic materials that are difficult to inject.