AN ADVANCED DEBURRING AND CHAMFERING SYSTEM (ADACS) BASED ON THE ENHANCED MACHINE CONTROLLER (EMC) Keith Stouffer, Fred Proctor, Elena Messina and Jim Albus Intelligent Systems Division National Institute of Standards and Technology Building 220, Room B124 Gaithersburg, Maryland 20899 USA ABSTRACT An autonomous finishing workcell for deburring and chamfering high precision machined parts has been developed by engineers at the National Institute of Standards and Technology (NIST) working with United Technologies Research Center (UTRC) and Pratt & Whitney. This Advanced Deburring and Chamfering System (ADACS) is an application of the NIST Enhanced Machine Controller (EMC). The EMC is an open architecture hierarchical controller suitable for a variety of high-fidelity real-time control systems. Within ADACS, a feature-based process planning system generates the deburring and chamfering paths based on parameters and edges selected by a manufacturing engineer from a solid model Computer Aided Design (CAD) definition of the part. Simulation of the paths as well as collision detection is performed before the generated tool paths are downloaded to the robot/machine tool, and finishing tool. The ADACS uses active force control in the tool to control stiffness of the tool normal to and tangential to the chamfer edge. The ADACS is being installed in a commercial application for finishing jet engine components at Pratt & Whitney. INTRODUCTION The finishing operation is a critical step in the manufacturing of parts manufactured from hard metals. After a part has been machined, a finishing operation is usually required to remove excess material, or burrs, to bring the part within tolerance of the specification. The primary finishing processes are deburring and chamfering. In the past, and still presently, the finishing operation has been performed manually at a burr bench with a hand held spindle grinder. This hand-crafting of parts tends to be expensive, inconsistent and inaccurate. Manual finishing can account for 10%–20% of the total labor cost and approximately 10%–30% of the manufactured parts need rework after the manual finishing process. Automation of the finishing process would prove to be very beneficial. By automating the finishing and chamfering processes, tolerances could be held to less than 0.08 mm (0.003 in), the finishing costs could be reduced as much as 50%, and the rework rates could be nearly eliminated. The National Institute of Standards and Technology (NIST) and United Technologies Research Center (UTRC), under Navy ManTech funding, have developed the Advanced Deburring and Chamfering System (ADACS) which is capable of processing aerospace parts made from hard materials such as titanium and inconel. For aerospace parts, the ADACS must produce a precision 45 degree break edge, or chamfer, for part edge geometries such as modified and full radii. Features of ADACS include: • open architecture controller • operator–controlled, off–line graphical user interface exploiting CAD part models to off-line program and simulate finishing trajectories • automated extraction of features from edge data • active tooling to compensate for small position errors and to maintain a constant cutting force on the edge • tightly coupled coordination of tool and motion commands to achieve ramping and smoothing An open system built from open component technology was the major design paradigm used to achieve the ADACS system requirements for integration, flexibility, and extensibility. System design using an open architecture reference model with well-defined interfaces offers a sound approach to implementation that can be adapted to satisfy future requirements. The ADACS used the Enhanced Machine Controller (EMC) for its control architecture. The EMC is an open-architecture reference model with well- defined interfaces. This paper will show how the ADACS No approval or endorsement of any commercial product by the National Institute of Standards and Technology is intended or implied. Certain commercial equipment, instruments, or materials are identified in this report in order to facilitate understanding. Such identification does not imply recommendation or endorsement by the National Institute of Standards and Technology, nor does it imply that the materials or equipment identified are necessarily the best available for the purpose. This publication was prepared by United States Government employees as part of their official duties and is, therefore, a work of the U.S. Government and not subject to copyright. The research developed during the ADACS project was supported by the U.S. Navy ManTech Program.