COBEM99

SR20 Metrologia

Title:

PRACTICAL APPLICATION OF A MODULAR SPACE FRAME FOR VERIFICATION OF CO-ORDINATE MEASURING MACHINES (CMMS)

Summary :

ABSTRACT.IN THE PRESENT INVESTIGATION, A NEW FORM OF SPACE FRAME FOR RAPID VERIFICATION OF CO-ORDINATE MEASURING MACHINES (CMMS) IS PROPOSED AND APPLIED. THIS SPACE FRAME HAS THE FORM OF A TETRAHEDRON AND IS REFERRED TO AS A MODULAR SPACE FRAME AS DIFFERENT CONFIGURATIONS OF TETRAHEDRON CAN BE OBTAINED EASILY AND RAPIDLY. THE MODULAR SPACE FRAME COMPRISES MAGNETIC BALL LINKS AND A BALL PLATE. A TYPICAL MAGNETIC BALL LINK CONSISTS OF TWO MAGNETIC CUPS AND A CARBON FIBRE LINK, CONNECTING MAGNETICALLY, TWO HIGH ACCURACY SPHERES. A TECHNIQUE BASED ON A LASER INTERFEROMETER SYSTEM WAS DEVELOPED TO CALIBRATE THE MAGNETIC BALL LINKS AND THE BALL PLATE. THE VOLUMETRIC ERROR DATA OBTAINED WHEN A CMM MEASURES THE CALIBRATED MODULAR SPACE FRAME CAN BE USED TO VERIFY WHETHER A CMM MAINTAINS THE MANUFACTURER SPECIFICATIONS. THE EXPERIMENTAL RESULTS HAVE DEMONSTRATED THAT THE MODULAR SPACE FRAME SYSTEM HAS AN ACCEPTABLE REPEATABILITY AND PROVIDES A PRACTICAL AND COST EFFECTIVE MECHANICAL ARTEFACT TO DETERMINE THE VOLUMETRIC ACCURACY OF SMALL/MEDIUM SIZED CMMS. THE DEVELOPED TECHNIQUE CAN BE APPLIED FOR CALIBRATION, VERIFICATION, PERIODIC REVERIFICATION AND ACCEPTANCE TEST OF ANY TYPE OF CMM. KEYWORDS: CALIBRATION, VERIFICATION, CO-ORDINATE MEASURING MACHINES

Author :

Silva, Joao Bosco A.

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