Automating Robot Programming in the Cleaning and Deburring Workstation of the Amrf

In the Cleaning and Deburring Workstation, two robots cooperate to accomplish deburring, buffing, cleaning, and handling of machined metal parts. A technique has been developed which uses part geometry data to generate robot paths automatically. Using a graphics interface, an operator specifies how a part is to be gripped, fixtured, deburred, buffed, and cleaned. A path planner combines this process plan with geometry data to compute robot paths. A workstation controller coordinates the actions of both robots, allowing various steps in the finishing process to be performed simultaneously. This paper describes the methods used to automate the finishing process. INTRODUCTION The Automated Manufacturing Research Facility (AMRF) of the National Institute of Standards and Technology (formerly NBS) is a research testbed consisting of three machining workstations, an inspection workstation, a distributed material handling workstation, and a cleaning and deburring workstation [1]. Initiated in the early 1980s with funds from the Manufacturing Technologies Program of the U.S. Navy, the AMRF serves as a vehicle for the development and testing of techniques to automate small-batch manufacturing. Traditional automation strategies are normally not applicable to small-batch manufacturing. The lot sizes are small, and the inventory of part types large, so machinery dedicated to the performance of single part-dependent tasks is not cost-effective. Equipment that can fulfill diverse roles without human intervention is necessary for the effective automation of a smallbatch factory. This type of flexibility is provided by robots, which can be programmed to perform a variety of tasks automatically. The AMRF has been partitioned into workstations dedicated to performing some particular duty. One or more robots serve each workstation, programmed to position and process parts depending upon the part geometry. This allows for a large number of different parts to be processed by the same equipment without manual assistance. The Cleaning and Deburring Workstation The Cleaning and Deburring Workstation (CDWS) has been assigned the task of finishing the parts machined at the other workstations. Finishing processes include deburring of edges with rotary tools, buffing with cloth wheels, brushing with wire or abrasive wheels, and washing. The research effort began in 1985 [2], with research evolving from deburring to automating robot programming. _____________________________________________________________________________ This work was partially funded by the U.S. Navy MANTECH Program. This paper was prepared by U.S. Government employees and is not subject to copyright. Equipment listings do not imply a recommendation by NIST, nor do they imply that the equipment is necessarily best for the purpose. Equipment in the CDWS consists of two cooperating robots with a rotary vise for part fixturing placed in their common volume, tray stations for part transfers in and out of the workstation, a four-head buffing jack, and a washer/dryer system. A Unimate 2000 six-axis hydraulic robot is equipped with a gripper for part handling and buffing. A PUMA 760 six-axis electric robot is fitted with a quick change wrist which allows for selection between various deburring tools and a gripper. Both the 2000 and the 760 participate in part handling. Deburring is assigned to the 760, while buffing and tray transfers are assigned to the 2000. An overhead view of the workstation layout is shown in figure 1. Tray Station #1 Tray Station #2 Vise Tool Rack Puma 760 Robot Dust Collector Buffing Wheels Washer-Dryer System Unimate 2000 Robot Rotary Index Table