2010 R&D 100 Winner
Today’s large machine tools must be carefully calibrated to perform increasingly complex tasks, but diagnosing errors can be frustrating. Volumetric Accuracy for Large Machine Tools (VALMT), a partnership of Automated Precision Inc. (API), Rockville, Md.; The Boeing Company, Chicago, Ill.; Siemens, New York, N.Y.; Mag Cincinnati, Cincinnati, Ohio; and the National Center for Manufacturing Sciences, Ann Arbor, Mich., has pioneered a methodology, Volumetric Error Compensation (VEC) for large machine tools, to address the need for improving close tolerance and working accuracy for 5- and 6-axis machine tools.
VEC has previously been used, but it cost days in lost production and was expensive, requiring high technical expertise and sophisticated equipment. VEC from API uses the company’s T3 Laser Tracker patented Active Target to precisely calibrate large machine tools in a matter of hours. The measurements are done in a single coordinate system rather than along three axes, resulting in a true volumetric map of the machine tool’s accuracy. Advanced VEC software then processes the data in a matter of minutes with a special set of Chebyshev polynomials algorithms. The software calculates a polynomial-based kinematic equation to describe a global free-form error model for each machine so it can then compensate any co-ordinate within the machine tool’s working volume.
Test results have confirmed at least a four-fold improvement in machine tool accuracy versus traditional calibration methods.
Technology
Laser-tracking calibrator for machine tools
Developers
Automated Precision Inc.
Siemens Automation
Mag Cincinnati
National Center for Manufacturing Sciences
Boeing Phantom Works
Development Team
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| (l-r): Bei Jin, Kam Lau, and Helen Qiao
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The Volumetric Error Compensation (VEC) Development Team from Automated Precision Inc.:
Ben Jin
Kam Lau
Helen Qiao
