COBEM99

SR20 Metrologia

Title:

ANÁLISE COMPARATIVA DOS RESULTADOS DE MEDIÇÃO DA TEXTURA DE SUPERFÍCIES USINADAS, MEDIDAS COM APALPADORES ÓPTICOS E MECÂNICOS

Summary :

A COMPARATIVE ANALYSIS ON MACHINED SURFACE TEXTURE MEASUREMENTS OBTAINED FROM OPTICAL FOLLOWERS AND STYLUS INSTRUMENTS ABSTRACT: MANY METALLIC SURFACES REQUIRE FINE FINISHING TO PROPERLY PERFORM THEIR TECHNOLOGICAL ROLE. SURFACES FOR OPTICAL PARTS AND MEASUREMENT DEVICES, CHARACTERIZED BY RA VALUES FROM A FEW NANOMETERS TO A HUNDREDTH MICROMETER TO ARE TYPICAL EXAMPLES. FOR SUCH SMALL ROUGHNESS VALUES, MEASUREMENT IS SUBSTANTIALLY DIFFICULT AND MAY NOT BE PERFORMED USING STYLUS INSTRUMENTS. IN HIGHLY FINISHED SURFACES, THE GEOMETRY OF THE TIP STYLUS AND THE MEASUREMENT FORCE MAY CAUSE SIGNIFICANT DISTORTION BETWEEN THE REAL SURFACE TEXTURE AND MEASUREMENT RESULTS. IN SOME CASES, THE MOST IMPORTANT SOURCE OF ERROR IS THE SURFACE/STYLUS CONTACT. ALTHOUGH OPTICAL FOLLOWERS CAPTURE SURFACE PROFILES WITHOUT CONTACT, OTHER PROBLEMS MAY OCCUR SUCH AS THE EFFECT OF ENVIRONMENTAL CONDITIONS WHICH BECOMES INCREASINGLY IMPORTANT. IN ADDITION, SURFACE MICROGEOMETRY AND ITS REFLECTION CAPABILITY MAY CAUSE CONSIDERABLE DEVIATIONS. IT IS ALSO NOT POSSIBLE TO COMPARE RESULTS OBTAINED FROM STYLUS AND OPTICAL FOLLOWER AS A CONSEQUENCE OF THE DEEPER PENETRATION OF THE OPTICAL BEAM INTO SURFACE VALLEYS. THIS STUDY PRESENTS A COMPARATIVE ANALYSIS BETWEEN TEXTURE MEASUREMENTS OF A NUMBER OF MACHINED SURFACES CARRIED OUT USING BOTH A STYLUS INSTRUMENT AND AN OPTICAL FOLLOWER. CAUSES FOR THE DISCREPANCIES AND A REFERENCE GUIDE FOR LATER USE OF BOTH TYPES OF INSTRUMENTS WILL ALSO BE DISCUSSED. KEY WORDS: SURFACE, TEXTURE MEASUREMENT, STYLUS INSTRUMENT, OPTICAL FOLLOWER

Author :

Almeida, Cláudio R. R. de
Bet, Luciano 0
Boehs, Lourival 0
Mostiack, Gustavo Rene

Paper View :