Analysis and Characterization of Machined Surfaces with Aesthetic Functionality
Francesco Giuseppe Biondani*,, Giuliano Bissacco*, Lukáš Pilný**, and Hans Nørgaard Hansen*
*Department of Mechanical Engineering, Technical University of Denmark
Produktionstorvet, Kgs. Lyngby 2800, Denmark
**Novo Nordisk A/S, Hillerød, Denmark
The generation of fine machined surfaces with high gloss is an important topic in mould manufacturing. The surface gloss can be characterized by means of scattered light sensors and a representative parameter such as Aq. In this paper, in-line measurements of scattered light distribution are compared with roughness parameters calculated using a confocal microscope, in order to assess surface aesthetic quality. Several surfaces have been machined by means of high precision milling, producing different surface topographies. Surface characterization has been performed on a machine using a scattered light sensor, and using a confocal microscope in laboratory conditions. The calculated Aq parameter is compared with the amplitude roughness parameters Sa and Sq, and with hybrid parameters Sdq and Rdq representing the average slope of the surface features. Scanning electron microscope (SEM) images are used as visual benchmarks to identify the parameters’ correlation with the visual appearance. A different linear trend of the relationship between Aq, Rdq, and Sdq is observed. The description of the surface quality through Sa or Sq instead is found to be insufficient. This is explained by means of SEM pictures showing a dramatic influence of the smeared material over the machined surface.
-  K. D. Thoben, S. Wiesner, and T. Wuest, “‘Industrie 4.0’ and Smart Manufacturing – A Review of Research Issues and Application Examples,” Int. J. Automation Technol., Vol.11, No.1, pp. 4-19, 2017.
-  Y. Kobayashi, K. Shirai, Y. Hara, T. Mizoguchi, and K. Kawasaki, “Generation and Assessment of Random Surface Texture over a Wide Area,” Int. J. Automation Technol., Vol.5, No.2, pp. 185-189, 2011.
-  T. Hirose, Y. Kami, and T. Shimizu, “Development of On-Machine Measurement Unit for Correction Processing of Aspheric Lens Mold with High Numerical Aperture,” Int. J. Automation Technol., Vol.8, No.1, pp. 34-42, 2014.
-  A. Schöch, A. Salvadori, I. Germann, S. Balemi, C. Bach, A. Ghiotti, S. Carmignato, A. L. Maurizio, and E. Savio, “High-speed measurement of complex shaped parts at elevated temperature by laser triangulation,” Int. J. Automation Technol., Vol.9, No.5, pp. 558-566, 2015.
-  I. S. Jawahir, E. Brinksmeier, R. M’Saoubi, D. K. Aspinwall, J. C. Outeiro, D. Meyer, D. Umbrello, and A. D. Jayal, “Surface integrity in material removal processes: Recent advances,” CIRP Ann. – Manuf. Technol., Vol.60, No.2, pp. 603-626, 2011.
-  M. Shimizu, H. Sawano, H. Yoshioka, and H. Shinno, “On-Machine Surface Texture Measuring System Using Laser Speckle Pattern Analysis,” Int. J. Automation Technol., Vol.10, No.1, pp. 69-77, 2016.
-  L. De Chiffre, P. Lonardo, H. Trumpold, D. A. Lucca, G. Goch, C. A. Brown, J. Raja, and H. N. Hansen, “Quantitative Characterisation of Surface Texture,” CIRP Ann. – Manuf. Technol., Vol.49, No.2, pp. 635-652, 2000.
-  L. De Chiffre, H. Kunzmann, G. N. Peggs, and D. A. Lucca, “Surfaces in precision engineering, microengineering and nanotechnology,” CIRP Ann. – Manuf. Technol., Vol.52, No.2, pp. 561-577, 2003.
-  T. Hayashi, Y. Takaya, N. Motoishi, and Y. Nakatsuka, “Surface Inspection of Micro Glass Lens Mold Based on Total Angle Resolved Scattering Characterization,” Int. J. Automation Technol., Vol.4, No.5, pp. 1-7, 2010.
-  H. N. Hansen, K. Carneiro, H. Haitjema, and L. De Chiffre, “Dimensional micro and nano metrology,” CIRP Ann. – Manuf. Technol., Vol.55, No.2, pp. 721-743, 2006.
-  A. R. Hanson, “Measurement Good Practice Guide No.94, Good Practice Guide for the Measurement of Gloss,” National Physical Laboratory, 2006.
-  ASTM D523-14, “Standard Test Method for Specular Gloss,” ASTM Int., 2018.
-  J. Seewig, G. Beichert, R. Brodmann, H. Bodschwinna, and M. Wendel, “Extraction of shape and roughness using scattering light,” Proc. SPIE, Vol.7389, p. 73890N-1-11, 2009.
-  L. Pilný and G. Bissacco, “Development of on the machine process monitoring and control strategy in Robot Assisted Polishing,” CIRP Ann. – Manuf. Technol., Vol.64, pp. 313-316, 2015.
-  T. Nomura, T. Nagasaki, and M. Ito, “Development of Inspection Machine that Detect Small Particles Added on Surface with Precise Pattern by Capturing Backwards Scattered Polarized Light,” Int. J. Automation Technol., Vol.6, No.6, pp. 781-791, 2012.
-  L. Pilný, G. Bissacco, and L. De Chiffre, “Validation of in-line surface characterization by light scattering in Robot Assisted Polishing,” Proc. of the 3rd Int. Conf. on Virtual Machining Process technology (VMPT), p. 8, 2014.
-  Verband der Automobilindustrie, “VDA 2009, Geometrische Produktspezifikation Oberflächenbeschaffenheit Winkelaufgelöste Streulichtmesstech-Nik Definition, Kenngrøßen Und Anwendung (Light Scattering Measurement Tech.),” 2009.
-  R. Bordmann and J. Seewig, “Non-Contact Surface Metrology by Means of Light Scattering,” Q. J. Wang and Y.-W. Chung (Eds.) “Encyclopedia of Tribology,” Springer, pp. 2434-2440, 2013.
-  J. Bohm, M. Jech, and M. Vellekoop, “Analysis of NM-Scale Scratches on High-Gloss Tribological Surfaces by Using an Angle-Resolved Light Scattering Method,” Tribol. Lett., Vol.37, No.2, pp. 209-214, 2010.
-  N. A. Feidenhans’l, P. Hansen, L. Pilný, M. H. Madsen, G. Bissacco, J. C. Petersen, and R. Taboryski, “Comparison of optical methods for surface roughness characterization,” Meas. Sci. Technol., Vol.26, No.8, p. 085208, 2015.