Selection and sequencing of machining processes for prismatic parts using process ontology model

An essential part of process planning is to select the appropriate manufacturing processes and to determine their order from manufacturing knowledge. Ontology technology is considered an effective alternative for knowledge representation. Some studies have suggested a good process knowledge representation model based on heavyweight ontology, but this has inevitably resulted in limited scalability. Other studies have proposed frameworks to reason the appropriate machining processes for a feature, but have not sufficiently taken into account the manufacturing requirements. This paper thus presents an approach to select and sequence the machining processes for features using an ontology-based representation model as well as the corresponding inference rules. The ontology includes concepts including features, machining process, process capability with relevant properties, and relationships between concepts. The reasoning mechanism deduces a set of appropriate machining processes for individual features. Among these is the most appropriate final process determined by matching the accuracy requirements of a specific feature with the capability of the candidate processes. The preceding machining process is then selected so that the precedence relationship constraint between the processes is met until no further precedent processes are required. The proposed approach is neutral in that it is not subject to a specific restriction, such as a particular tool maker, and therefore can provide an interoperable and reusable platform.