COBEM99

SR20 Metrologia

Title:

AVALIAÇÃO DO ERRO DE RETILINEIDADE,A PARTIR DA CALIBRAÇÃO DO ERRO ANGULAR, DE UMA MM3C

Summary :

MAKERS AND USERS OF THREE COORDINATE MEASURING MACHINES HAVE GREAT INTEREST IN DEVELOPING METHODOLOGIES THAT ALLOW THE DETERMINATION OF ERRORS AND THE IMPROVEMENT OF THE PERFORMANCE OF THOSE MACHINES. AMONG THOSE METHODOLOGIES, THE CALIBRATION PROCEDURES, THE ERROR COMPENSATION SYSTEMS AND THE NUMERIC METHODS FOR THE TREATMENT AND ANALYSIS OF ERRORS ARE SOME OF THE FEW LATELY STUDIED. IT IS ALREADY KNOW THAT IT IS NECESSARY THE PREVIOUS KNOWLEDGE OF THE BEHAVIOR OF THE MACHINE ERRORS IN ORDER TO BUILT AN ERROR COMPENSATION SYSTEM. THE INDIVIDUAL MACHINE ERRORS CAN BE OBTAINED THROUGH CALIBRATION PROCEDURES AND THEY CAN BE COMBINED APPROPRIATELY THROUGH A MATHEMATICAL MODEL, TO GENERATE THE EXPRESSIONS OF THE VOLUMETRIC ERRORS OF THE MACHINE. USUALLY, THE INDEPENDENCE AMONG THE INDIVIDUAL ERRORS IS ADOPTED WHEN THE MACHINE ERROR MODEL IS BUILT. HOWEVER, IF THE MACHINE GEOMETRY IS ANALYZED, THE DEPENDENCE BETWEEN THE STRAIGHTNESS ERROR AND THE ANGULAR ERROR CAN BE NOTED. THE OBJECTIVE OF THIS WORK IS TO EVALUATE THE CORRELATION BETWEEN THE STRAIGHTNESS ERROR IN A CERTAIN DIRECTION DUE TO THE TRANSLATION MOVEMENT IN ANOTHER DIRECTION AND THE OBSERVED PITCH OR YAW ERROR. A BROWN & SHARP MOVING BRIDGE COORDINATE MEASURING MACHINE (CMM) WAS USED FOR THE EXPERIMENTAL EVALUATION. THE FORMULATION PROPOSED IN THIS WORK TO EXPRESS THIS CORRELATION MINIMIZES THE NUMBER OF CALIBRATION NECESSARY TO EVALUATE THE MACHINE BEHAVIOR. THE MEASUREMENT OF THE STRAIGHTNESS ERROR IN THE CMM STUDIED, CAN ONLY BE PERFORMED IN A RANGE OF APPROXIMATELY 100 MM, DUE TO THE OPTICS USED FOR THE CALIBRATION. OUR FORMULATION ALLOWS TO EVALUATE THIS GUIDE ERROR IN A RANGE LARGER THAN THE PERMITTED BY THE CALIBRATION PROCEDURES. KEYWORDS: THREE COORDINATE MEASURING MACHINES, STRAIGHTNESS ERROR AND ANGULAR ERROR.

Author :

Giacomo, Benedito Di
Marques, Alessandro 0
Vieira Sato, Denise Pizarro

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