CONCLUSION

The concept of features is at the centre of product development domain. While their definitions may take varying forms, their application-dependent nature is widely appreciated, so is their potential of integrating the different phases of a product development cycle. The feature taxonomy defined in ISO 10303-224 seems to provide a standardised guideline that is comprehensive enough for machining purposes. When a feature is defined as a collection of surfaces or a closed solid, volumetric feature seems to fare better for machining applications. There are a number of advantages of working with volumetric features. It is easier to associate a machining operation with a volumetric feature. Feature volumes can define precisely the stock to be machined, thus enabling the determination of machining cost and time. With a volumetric approach, it becomes possible to obtain the intermediate shapes of the workpiece. A volumetric representation enables a more complete description of feature-feature interactions. When volumetric features are derived from the surface features on a part, protrusion features become invalid, as they do not contribute directly to volumetric features as depression features usually do. In order to guarantee the validity of the feature volumes for the part, it is also essential to take the blank into consideration.