Injection molded parts often have small complex features so the construction of models is usually the most time-consuming aspect of model analysis.
It is not always necessary to create a complete model. Simplifications that save modeling and analysis time can often be made. The fundamental principle is that the model must be equivalent to the flow in the real part. Flow is dictated by the following elements, listed according to their significance.
The aim should therefore be to create a model with the same thickness, flow length and volume as the real part. When good practices are observed, a simple model will generally provide similar results to a more complex model of the same part.
Failure to plan the modeling procedure can result in needless repetition so always consider the order in which the model will be created. Symmetry will also dictate the order of creation. Parts with circular features can be modeled by first creating the round features and then connecting these together. Generally, it is good practice to start from detailed sections in the middle of the model and then work outwards.
Most parts exhibit some symmetry and you should always look for this in the part to be modeled. There are various functions within the product that exploit symmetry and greatly reduce modeling time. Surfaces can be copied by translation, rotation about an axis, or by mirroring through a plane.