A STEP-Compliant Approach to Turning Operations

Abstract

There is no doubt that today manufacturing is more competitive and challenging than ever before in trying to respond to "production on demand". Companies from east and west and all over the world have changing rules of business and need to collaborate beyond geographic boundaries with the support of the rapid advancement of information technology associated with manufacturing technology. To satisfy customers' demands for product variety and the industrial need for high precision, numerically controlled machining with multiple axes and sophisticated machine tools are required. Due to the complexity of programming there is a need to model their process capability to improve the interoperable manufacturing capability of machines such as turning centres. This thesis focuses on the use of the new standard; ISO 14649 (STEP-NC), to address the process planning and machining of discrete turned components. It explores how ISO 14649 can be used to combine turning and milling operations to support interoperable CNC manufacturing of rotational asymmetric components at a single turning centre. The STEP-NC standard presents the opportunity to develop a new structure for feature-based process planning to address the process planning and machining of discrete components. This research proposes a STEP Compliant NC structure for generation of ISO 14646 code which can be used for turned component manufacture. The major contribution of this research is the creation of a computational environment for a STEP-NC compliant system for turning operations namely SCSTO. SCSTO is the experimental part of the research, supported by specification of information models and constructed using a structured methodology and object-oriented methods. SCSTO was developed to generate a Part 21 file based on machining features to support the interactive generation of process plans utilising feature extraction. Case study components have been tested to prove that the new approach (STEP-NC) can be used to generate code equivalent to currently used G-codes with some benefits such as the elimination of the post-processor. An important aspect was the need to overcome the complexities of component geometry including milling features so as to have ability to manufacture turn/mill components.

A Framework for a Development of an Intelligent CNC Controller Based on Step-NC

“…Further research, Nassehi was developed a IP3AC using Java programming language and presented a prototype namely process planning system (PPS) with two-strategy for part program generation; i) general workplan generation; and ii) specific workplan generation. On the other hand SCSTO was developed to generate a Part 21 file based on machining features to support the interactive generation of process plans utilizing feature extraction [12] and this system based on turning operation.…”