Mjerna sposobnost optičkog sustava za očitanje veličine otiska tvrdoće

master's thesis

• Title (english): Measurement capability of an optical system for reading the hardness indentation
• Author: Danijel Grlić
• Mentor: Željko Alar (mentor)
• Granter: University of Zagreb; Faculty of Mechanical Engineering and Naval Architecture; Zagreb
• Defense date and country: 2016-12-08, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Mechanical Engineering

Abstract

Mjerenje tvrdoće je jednostavan postupak, ali nepoznavanje faktora koji utječu na mjerenje tvrdoće može prouzrokovati velike nesigurnosti. Sustav za mjerenje veličine otisaka tvrdoće kod Vickersove metode jedan je od tih faktora, tj. najznačajniji izvor nesigurnosti mjerenja. U radu su opisani sustavi za mjerenje veličine otisaka tvrdoće kod Vickersove metode, te jedan sustav u razvoju, sustav LIMS 320/HV. Navedeni su njegova konstrukcija i karakteristike. Proveli su se postupci podešavanja i direktnog umjeravanja sustava LIMS 320/HV. Podešavalo se namještanjem duljine podešavanja pri povećanjima 5x, 10x, 20x i 40x pomoću mjernih skala te su kao rezultati dobiveni faktori podešavanja. Sustav se umjeravao pomoću mjernih skala čime se prikazala mjerna nesigurnost sustava. Analizom rezultata su dobivene mjerne sposobnosti za svako povećanje i ukupna mjerna sposobnost sustava izražena eksponencijalnom jednadžbom. Usporednim mjerenjem referentnih otisaka na referentnim etalonskim pločicama (IN45180G-461,9HV1, 33P1825-204,4HV20 i IN6807G-808,7HV50) potvrđeno je da je sustav primjenjiv za veličine dijagonala iznad 0,2 (ili 0,3) mm, dok je za vrijednosti ispod 0,2 mm mjerna nesigurnost velika.

Abstract (english)

Hardness measurement is a simple procedure, but lack awareness of factors that affect hardness measurement can lead to large uncertainty. Indentation measurement systems for Vickers hardness method is one of those factors, i.e. most significant source of measurement uncertainty. In this paper, indentation measurement system for Vickers method are described, and one who is in development, system LIMS 320/HV. His structure and characteristics are described. Procedures of alignment and direct calibration were conducted on system LIMS 320/HV. Alignment was made with adjustment of alignment length on magnifications of 5x, 10x, 20x and 40x with stage micrmeters and obtained results were alignment factors. Calibration of system was made with stage micrometer which showed measurement uncertainty. Results were analyzed and gave calibration and measurement capability for every magnification and total calibration and measurement capability of system, expressed in exponencial equation. Comparative measurement of reference indents on a standard reference blocks (IN45180G-461,9HV1, 33P1825-204,4HV20 and IN6807G-808,7HV50) confirmed that the system is effective for the size of the indent diagonal above the 0.2 (or 0.3) mm, while for values below 0.2 mm measurement uncertainty is high.

• Keywords: Ključne riječi; Mjerenje tvrdoće; mjerna nesigurnost; mjerna sposobnost; umjeravanje; sustav za očitanje veličine otiska LIMS 320/HV.
• Keywords (english): Key words; Hardness measurement; measurement uncertainty; calibration and measurement capability; calibration; indentation measurement system LIMS 320/HV
• Language: croatian
• URN:NBN: urn:nbn:hr:235:903245
• Study programme: Title: Mechanical Engineering; Study programme type: university; Study level: graduate; Academic / professional title: magistar/magistra inženjer/inženjerka strojarstva (magistar/magistra inženjer/inženjerka strojarstva)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2019-05-22 18:15:02