Using occurrence numbers to reduce model size

Occurrence numbers can be used to simplify the amount of modeling required for an analysis by specifying the number of times that a given flow path is repeated.

However, you must model the full part, instead of using occurrence numbers, when you want to run the following analyses:

• Cool analysis
• Warp analysis
• Stress analysis

Before we consider modeling simple parts using occurrence numbers it is helpful to understand the concept of symmetrical flow paths. Flow paths are said to be symmetrical when the physical geometry of the flow path is symmetrical and when the volume of plastic flowing through the paths are identical.

There are 3 main combinations of parts and runner systems:

• Direct injection into a cavity (a)
• Injection via a runner system into a multi-gated cavity (b)
• Injection via a runner system into multiple cavities (c)

Of course there are many other possible combinations apart from these three basic combinations, but for simplicity they will not be described here. By default, all surfaces and elements in the model are considered to have an occurrence number of 1.

Occurrence numbers can be specified using (Geometry tab > Properties panel > Edit) and then setting the Occurrence number on the Part Surface Properties tab.

Occurrence number details are saved in the model file and are automatically read into the program with the model.