STEP NC Tool path programming in an intelligent Step NC Manufacturing Context Adopted and edited from a presentation made by: Raphaël LAGUIONIE - Matthieu RAUCH – Jean-Yves HASCOET Institut Recherche Communications Cybernetique Nantes (IRCCyN) France.

Scope Introduction & Applications Step_NC: A new approach –Lacks of curent G-code –A new vision: Step_NC –Machining strategies in a Step_NC file –The Korean Step_NC prototype Pattern strategies –A new method to build toolpaths –Proposition of integration in Step_NC standard Validation of the proposition –Implementation in PosSFP (Shop Floor Programming System) –Development of a Step_NC numerical chain –From the CAD model to the machined part… Conclusion

Introduction The STEP-NC AP238 Standard The STEP-NC AP238 standard is the result of a ten year international effort to replace the RS274D (ISO 6983) M and G code standard with a modern associative language that connects the CAD design data used to determine the machining requirements for an operation with the CAM process data that solves those requirements. Enabling e-Manufacturing for Mechanical Parts STEP-NC allows manufacturing organizations to seamlessly share machining and measurement information between machines and over the Internet. The emerging STEP-NC technology is yielding process improvements including a 15% reduction in machining time. The automated measurement and compensation enabled by STEP-NC promises to yield parts that meet higher accuracy requirements for less cost. The integrated simulation and verification enabled by STEP-NC promises to guarantee that every part will be made correctly and that production will stop whenever cuts are about to be made that do not meets design requirements. Resources: Step Tools, Inc.

Working Steps & Advanctages Working Steps STEP-NC changes the way that manufacturing is done by defining data as "working steps": a library of specific operations that might be performed on a CNC machine tool. In other words, it breaks down every machining operation into the steps required to perform the operation. In the past, CNC machine tools had to be programmed using G and M codes (from ISO 6983), which were instructions that only told the machine what moves to make, without any semantic content that referred to the part being processed. STEP-NC will make G and M codes obsolete. Advantages With the concept of "working steps" in place, the manufacturing process becomes streamlined. Now, a machine tool can receive a file with STEP-NC data, "know" what it means, and proceed milling the piece without any more instructions. There will be no more programming the machine tool for each individual piece. Moreover, the benefit of the standard goes further. With a set of standard "working steps" in place, all manufacturers will be able to share information reliably and instantaneously. A STEP-NC converted CAD file that is completed on the east coast can be sent over the internet to a machine shop on the west coast and they can immediately start milling the part. Resources: Step Tools, Inc.

Applications Step NC will enable:- Smart Process Control Smart Process Monitoring Smart Manufacturing

The current programming standard : G-code CAM Post-processor M216 G0 Z25 G0 X50 Y60 G1 X95 M02 G- Code Based on principles of the 60’s Ambiguous semantics in some cases Vendor-specific extensions Difficulty of changes on the machine tool Impossible Feed back Use of post-processors As many configurations as CAM softwares / machine tools more than 4500 today Step_NC: a new approach

Benefits of Step_NC A new vision of the numerical chain Total integration of CAD-CAM-CNC No information lost Implementation of a single file Bidirectional data flow Step_NC: a new approach No more post-processors, no G & M codes Machine-unspecific program No more post-processors, no G & M codes Machine-unspecific program

Comparison G code – Step_NC Step_NC: a new approach

CNC in Step_NC numerical chain Step_NC: a new approach

Structure of a Step_NC file … Step_NC: a new approach

Korean prototype of Step_NC numerical chain 11 PosSFP : Feature recognition Choice of machining strategies attributes Step_NC file generation Machining entities Step_NC: a new approach

Study situation in Step_NC development First step : Goal : Interpreted programming Evolution with : Integrated programming Advanced programming Step_NC: a new approach

First step : Contribution to standard development Enrichment of strategies proposed in Step_NC : Pattern strategies : GUIDE CURVE + PATTERN Exemples of strategies built on pattern curves : Trochoïdal milling : Plunge milling : Pattern strategies : a new method to build toolpaths

Validation of this proposition of integration 14 CAD part Machining PosSFP Reading tools Toolpath generation Adaptation Step 1 : Implementation of trochoidal milling in : - Step_NC Standard - PosSFP Step 2 : Building of reading tools and toolpaths generators Step 3 : Machining test parts Step_NC Strategy parameters Toolpaths Step_NC File Integration of pattern strategies in Step_NC

Conclusion & More Benefits of Step NC Creation of an interpreted Step NC numerical chain First Step through advanced programming possibility to work with Step NC on conventional means Interest of pattern strategies Generation simplicity Few attributes needed to generate a complete toolpath Easy portability Compatibility with Step NC standard and high level programming Enrichment of Step NC possibilities Pattern strategies Step NC Conclusion - G-code programming is no more the solution - Bidirectional data flow - 1 single file (no lost of data, no redundancy, etc.) - Less correction time - Step_NC file portability - Total integration of CNC – feed-back to design and NC planning - Capitalization of shop floor feedbacks and experiences - New possibilities for toolpath generation and machining strategies - Ability of real-time adaptation and optimization of toolpaths and machining parameters Advanced Step NC