Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. PowerPoint to accompany Krar Gill Smid Technology of Machine Tools 6 th Edition Step-NC and Internet Manufacturing Unit 93

93-2 Objectives Define STEP and STEP NC Discuss the advantages to manufacturers of STEP NC Compare STEP with IGES Summarize the results reported by STEP users Describe the Super Model Project

93-3 STEP-NC Worldwide standard developed by ISO (International Standards Organization) –Extends STEP (Standard for Exchange of Product) model data so it can be used to define data for NC (Numerical Control) machine tools Process under development since 1984 STEP became full ISO standard in 1994 All leading CAD software vendors have implemented STEP into products

93-4 What is STEP? Extensible, comprehensive, international data standard for product data Created by international team of data experts Designed to give complete representation of product data throughout its entire life cycle

93-5 Working Steps STEP-NC changes way manufacturing done by defining data as working steps –Library of specific operations that might be performed on CNC machine tool CNC tools programmed using language called RS274 –40 years old and severely restricts range of information –Replaced with STEP-NC (ISO 14649)

93-6 Advantages of STEP Manufacturing process streamlined Manufacturers able to share information –Reliably, instantaneously with Internet Concentrates standardization effort on information content –Ensures standard will not be discarded when computing technology changes Common catalog shown in Table 93.1

93-7 STEP versus IGES Initial Graphics Exchange Specifications –Exchanges only data contained in graphics files –First appeared 25 years ago Computers used to create product designs Design files not compatible with each other IGES became workable to exchanging CAD files –Drawing exchanged, but failed to communicate meaning of drawing STEP formed so physical and logical information could be exchanged

93-8 STEP versus IGES In 1984, international effort to define methods for creating product data models that could be understood by computers International standards for these product data models became known as STEP –Has officially taken the place of IGES July of 2000 had almost every CAD system vendor with STEP translators Innovative feature of STEP was to insure compatibility and early commitment to testing

93-9 Developments CNC does not use G-codes –Everything it must know about how to move cutting tool is in product model's data base –Not necessary to create new, separate file of toolpath data Toolpaths are figured out in CNC –Eliminates need for post-processors Available for machining hard copies

93-10 The First Step STEP designed so all essential information about a product (not just CAD files) can be passed back and forth among users Designed for long term Maintained and extended by product data experts (meet three times a year) Users develop STEP because user-driven standards results-oriented

93-11 STEP Uses its own language called EXPRESS –Can be extended to any industry EXPRESS only widely available data language that describes complexities of solid geometry Neutral standard –Not owned by any CAD, CAM, or NC Control vendor

93-12 Results From STEP Users 10% improvement in data exchange reliability 10% process saving for noncomposite parts 50% process saving for composites 27% tool design saving on CAD/CAM systems 39% saving for NC CAM systems 75% reduction for process plan visuals 50 hrs saved in exchange of 12 data files by STEP Improved product quality and reduced cycle time Elimination of many compatibility problems

93-13 Super Model STEP-NC framework models –ISO for milling machine processing –ISO for turning machine processing –ISO for EDM machine processing –AP-213 of STEP captures macro process plan showing production order between machines

93-14 Manufacturing Outlines Supported by three systems –Rapid prototyping –Tooling –Production

93-15 Rapid Prototyping Functional and feature design produced using integrated CAD/CAM system Result output as ISO model read into Intelligent machine tool Tool Controller located at in-house shop of OEM or supplier Controller dynamically defines toolpath and part is cut

93-16 Tooling Designed by an OEM Result output as AP-203 or AP-214 file and sent to job shop File read into CAM system and uses system to define manufacturing features Result is set of AP-224 files put into CAM systems and resulting in ISO files ISO files read into machine tool Controller and part cut

93-17 Production Defined as integrated AP 213/ISO database –Contains manufacturing sequence and control files for each machine in line –Used to configure production run at setup time –Used as archive after end of production run –Developed using combination of CAD, CAM, and process planning tools