ISO/TC184/SC1/WG7 Status Report Regarding the Standardisation of a New NC Programming Data Interface Laboratory for Machine Tools and Production Engineering Aachen University of Technnology 08 October 1999

Outline Aims and strategy of ISO 14649 Overview of the current status in ISO/TC184/SC1/WG7 Integration with ISO 10303 Open issues

NC programming using ISO 6983 machine-specific part program with axis data generated by a postprocessor % N05 G54 N10 G00 Z10.000 N15 G91 G0 Z200 N20 T5 D1 WW N30 G90 M5 N35 G00 X0.000 Y-150.000 N40 G00 Z5.000 N45 M08 N50 S3183.000 N55 M03 N60 F1477.000 N65 G00 X60.000 Y-150.000 N70 G00 Z5.000 N75 G00 X60.000 Y-150.000 N80 G01 Z-0.500 ... vendor-specific extensions of the original standard only primitive motion and switch commands no standardised data format for spline processing and sophisticated NC technology

Aim of ISO 14649 Re-establish an accepted standard for the transmission of NC data to the shop floor! Provide motion control data based on splines for sophisticated, high-speed NC cutting operations Avoid intermediate data formats (CLDATA) Provide all necessary data for easy modification of NC data at the machine controller Task-oriented data structure Enable feedback of modified NC data from the shop floor to higher-level departments Minimize the need for data conversion by using standards for geometric representation

Use cases for ISO 14649 Note: ISO 14649 is a data interface (CAM to NC), not a user interface! The NC’s HMI may present the data to the operator in any desired form.

The workingstep concept Geometric and technological information will be linked, not mixed Each workingstep can be parameterised after instantiation, e. g. regarding tool, feed etc. Tool movements are combined into groups with clearly identifiable semantics Intelligent NC controllers can autonomously calculate tool movements for standard features

EXPRESS-G schema (simplified excerpt) workpiece workplan geometry S[0:?] L[0:?] machining_feature machining_workingstep geometry 1 L[0:?] pocket plane hole region machining_operation 1 L[0:?] plane_milling side_milling drilling tool technology geometry toolpath 1 strategy cutter_contact_trajectory cutter_location_trajectory parameterised_path

Current status: Modeling Final deliberations of WG7 22-24 Sept 1999: ISO 14649 Part 1: Introduction ISO 14649 Part 11: Process model for milling ISO 14649 Part 11/1: Tool model (will be obsolete after the arrival of ISO 13399) Parts 1, 11 and 11/1 will be put forward as DIS after the finalization of editorial work Part 11 defines 160 entities and 15 types (plus references from ISO 10303) Part 51 of ISO 14649 shall later present the mapping of Part 11 into the AIM Further process models for other technologies need to be developed

Current status: Selection of a physical file format Aim: To exchange NC programs at physical file level with high efficiency Coding of the EXPRESS data structure based upon ISO 10303 Part 21 Problem: How to define the logics and sequence of operations for complex NC programs a programming language seems to be needed US proposal: SDAI-Java Sequence coded in Java main() { wpl.exec() ... } #21 = WORKPLAN(...); #22 = WORKINGSTEP(...); ... Technological and geometric model coded in ISO 10303-21

Integration with ISO 10303: Geometry and topology The search for an existing geometric model lead to ISO 10303 Comprehensive geometric library in Part 42 Strategic advantage of using a future-oriented universal standard However: ISO 14649 has been aiming for a stand-alone standard, not a STEP application protocol A mapping of the required technological and machining data into STEP seemed not feasible Scope and size of STEP collides with the needed real-time behaviour for reading NC programs Transmit only process-relevant data Support file-based data transfer

Integration with ISO 10303: Intended data flow Process Planning NC Code Generation (CAM) Inspection Code Product Design (CAD) Milling Turning Grinding Inspection Features ISO 14649 Part 11, 21 Part 12, 22 Part 1X, 2X Part XX, XX STEP AP 213 (stock, tools, fixtures) STEP AP 224 (process sheet) All Manufacturing Execution STEP Part 4X Integrated Resources, via SDAI

Open issues Is there an alternative solution for sequencing? Could the sequence even for non-linear cases (branches, loops, ...) be coded in STEP Part 21? Advantage: Only one physical file needed. How close should the integration with STEP be? Is the request for a mapping into the Integrated Resources feasible and sensible? Is STEP prepared to integrate such process-specific, low-level, machine-oriented data? Does the mapping yield to the requirement of extremely compact and easy-to-process files at the shop-floor level?