Coordinate Measuring Machine Variations for Selected Probe Head Configurations

In coordinate measuring machine (CMM) research, there is often a need to measure the same feature repeatedly using multiple settings. However, the effects of changing the probe head configuration were previously unknown. The goal of this research was the determination of what effects the selection of the measurement plane, adaptor style, stylus length, and stylus size would have on the CMM’s ability to repeatedly measure a single diameter. An analysis of variance (ANOVA) study was conducted using a Brown & Sharpe MicroVal CMM. Three measurement planes (XY, XZ, and YZ), two adaptor styles (a star probe and an indexable head), two stylus lengths, and two stylus sizes were selected for the study. Ten measurements were taken on a single gage ring for each variable combination and the data were processed in SPSS. The results of this study indicate that if the measurement plane, stylus length, or stylus size were changed, the CMM would not repeatedly result in the same measurement reading. However, the user would be able to alter the adaptor style without affecting the resulting measurement. Additionally, the interactions of (a) measurement plane and adaptor style; (b) measurement plane and stylus length; (c) measurement plane, adaptor style and stylus length; (d) measurement plane, adaptor style and stylus size; and (e) measurement plane, adaptor style, stylus length, and stylus size all show significant measurement variations for the same feature. As future research is done on CMMs, care will be needed with the assumptions that are made when researching a specific effect. Based on this study, future researchers will have to determine whether observed changes are due to the probe head configuration or the changes they are studying. Introduction Reductions in product life-cycle durations are driving companies to develop and produce products at an ever-increasing rate. Industry experts are predicting the arrival of rapid manufacturing through the use of flexible manufacturing systems. Even a brief examination of industry periodicals such as Manufacturing Engineering, Technometrics, Production, Quality or Supply Chain Systems, would reveal discussions about highly integrated systems that are flexible, agile and lean. One result of these trends is the incorporation of coordinate measuring machines (CMMs), which allow companies to perform data collection and process verification within the manufacturing cell. Research on various coordinate metrology issues have paralleled the increased usage of CMMs in industry as inadequacies are uncovered and new needs develop. Research topics have covered such areas as the development of new probe compensation algorithms, sampling strategies, part orientation optimization, and computer generated inspection paths. As is often the case in research, assumptions have to be made in the interest of ensuring study feasibility. One such assumption is that the part orientation will not affect the measurements made by the CMM. This is one of the assumptions that this study challenged. Dr. Troy Ollison is an Assistant Professor of Technology and Engineering Technology at the University of Central Missouri in Warrensburg, Missouri. Ollison has been teaching both graduate and undergraduate courses for eight years. He is also an active member of the Society of Manufacturing Engineers as well as the Association of Technology Management and Applied Engineering (ATMAE). His primary interest and research areas are in metrology, rapid prototyping and materials processing and testing. Dr. Kevin Berisso is the Director of the AIDC Lab at Ohio University as well as an Assistant Professor in the Department of Industrial Technology. He received his BS in Industrial Technology from Ohio University and a MS in Industrial Technology from Indiana State University before taking a position with Applied Tactical Systems, a warehouse management software company. While at ATS, Dr. Berisso worked as a project engineer with companies such as Colgate-Palmolive and TRW. He then went to work for Delphi Automotive as a manufacturing engineer in the automotive battery division. In 2003 Dr. Berisso received his PhD in Technology Management from Indiana State University. He then proceeded to teach at Central Missouri State University before returning to OU in the summer of 2005. Included in Dr. Berisso’s research interests are RFID, direct part marking and the integration of AIDC with manufacturing processes and automation.”