Otherwise, when the feature boundary intersects with the workpiece borderline,the feature should be step.
Currently, this prototype of UPCi can deals with several simple features, including planar face, the associated operation attributes such as spindle speed, feedrate, coolant etc are reconstructed. These features and its operations are represented with STEP - NC entities. For each section, a pair of a feature and an operation can be generated. However, for a single feature it is common to have more than one, usually two, operations. It means it is possible for two adjacent sections to share one features . Hence, the next step is to identify the features by the placement and geometry information, remove the duplicated features and associate two operation to one feature as roughing and finishing. After this stage, these features and operations are organised by STEP-NC entities : project, work plan and working step etc.
The standard representation of the process plan for the part can than be generated and it can be used in other systems.This implementation of UPC i fully meets the design requirement for convenient future extensibility. For a new type of CNC to be supported in this system, only a new commands definition file is needed. No changes need to be made to the programmer it self. Additionally, choosing STEP-NC as the information capsule could guarantee semantic homogeneous between different systems due to the standard ' s resource independence, which would facilitate the fundamental goal of interchangeability.