Optical coherence tomography as a tool for non destructive quality control of multi-layered foils

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1 Optical coherence tomography as a tool for non destructive quality control of multi-layered foils Günther Hannesschläger, Alexandra Nemeth, Christian Hofer, Christian Goetzloff, Jens Reussner, Karin Wiesauer, Michael Leitner guenther.hannesschlaeger@recendt.at Page 1 RECENDT 2011 Günther Hannesschläger

2 Outlook RECENDT Motivation Optical coherence tomography Experimental setups Lab based measurements Moving foils In-line measurements Discussion Page 2 RECENDT 2011 Günther Hannesschläger

3 Non-universitary research institution Holders: - Upper Austrian Research (UAR) GmbH - Johannes Kepler University Linz - University of Applied Sciences Upper Austria Material characterisation and nondestructive testing Application oriented basic research up to tailored high-tech solutions Contact: RECENDT SciencePark2 / 2. OG Altenbergerstr Linz office@recendt.at Web: Page 3 RECENDT 2011 Günther Hannesschläger

4 Research Areas Optical Coherence Tomography Laser Ultrasound Photoacoustic Tomography Terahertz-Technology Infrared Spectroscopy Nanoindentation Customer specific applications Page 4 RECENDT 2011 Günther Hannesschläger

5 Motivation Multi layered foils Packaging Functional layers Production process One process (blown film extrusion line) More than 10 layers possible Goal: in line control of foil-parameters Page 5 RECENDT 2011 Günther Hannesschläger

6 Currently used methods Radiographic means Microtomic microscopy (off-line) Need for NDT-methods one possible solution: Optical Coherence Tomography (OCT) Page 6 RECENDT 2011 Günther Hannesschläger

7 Optical coherence tomography Let s have a closer look! OCT Page 7 RECENDT 2011 Günther Hannesschläger

8 Optical coherence tomography OCT is a non-destructive and contactless method based on white light interferometry for obtaining (in general) cross-sectional images revealing the internal structure of semi-transparent and turbid materials. Page 8 RECENDT 2011 Günther Hannesschläger

9 OCT in a nutshell OCT Optical coherence tomography Based on white light interferometry reflected light PD Incident light M BS S sample I D D[I r n N 1 I s,n.. Spectral distribution. Polarisation factor (0-1) OPD...optical path difference n N 1 2 I I s,n r ( g, n ) cos(2kopd)] Axial resolution l res 2ln 2 2 c around 1 10 µm Page 9 RECENDT 2011 Günther Hannesschläger

10 OCT in a nutshell Optical Coherence Tomography Time Domain OCT Fourier Domain OCT Spectral Domain OCT Swept Source OCT PD PD M DG M M BS BS S BS S S Page 10 RECENDT 2011 Günther Hannesschläger

11 amplitude Amplitude (a.u.) Intensität (a.u.) intensity amplitude Amplitude (a.u.) intensity Intenität (a.u.) intensity Intensität (a.u.) Signal processing Spectrum of Light 2-layer structure wavelength (nm) Wellenlänge (nm) Reference spectrum wavelength Wellenlänge (nm) Characteristics (example): 35 µs acquis. time (camera) bottle-neck: data processing display of data >100 db sensitivity k wavelength Wellenlänge (nm) 10k nm nm -1 1k FFT depth Tiefe ((µm) Page 11 wavenumber RECENDT 2011 Günther Hannesschläger Wellenzahl (1/ (1/µm)

12 OCT for Biomedical Applications Ophthalmology Dermatology Dentistry Endoscopy - Bronchoscopy - Urology - Cardiology Life Sciences (Cell imaging) St. Jude Medical Lawrence Livermore National Laboratory Lantis Laser Ltd., Biooptics World 2008 Review of ophthalmology 14, Page 12 RECENDT 2011 Günther Hannesschläger

13 Applications beyond biomedicine Plastics Jade Artwork Stifter et al., Appl. Phys. A 76, 947 (2003) Chang et al., Optics Engineering 49, (2010) Glass-fibre reinforced composites H. Liang et al. Opt. Exp. 13, 6133 (2005) Stifter et al., Meas. Sci. Technol. 19, (2008) Multi-layered foils Paper Laser drilled holes Prykäri et al., Optical Review 17, 218 (2010) Wiesauer et al., Optics Express 13, 1015 (2005) Webster et al., Optics Letters 35, 646 (2010) Page 13 RECENDT 2011 Günther Hannesschläger

14 Industrial SD-OCT system Industrial OCT system spectral domain detection high speed (28 Hz) high resolution (< 5µm) high sensitivity stable and compact dedicated probe head tailor made different spectral regions highly portable Page 14 RECENDT 2011 Günther Hannesschläger

15 Conventional probe head Probe head with dedicated scanning lens Beam scanned across sample cross sectional images Scanning mirror Light beam Lens OCT Image Image size: 120 µm Depth ~500 µm lateral Sample Page 15 RECENDT 2011 Günther Hannesschläger

16 Lab based measurements 9.2 µm 38.8 µm 10.1 µm 29.4 µm 11.0 µm Image size: 120 µm Depth, ~500 µm lateral 10.8 µm 30.9 µm 10.1 µm 10.5 µm 14.5 µm 9.5 µm Page 16 RECENDT 2011 Günther Hannesschläger

17 Production site at Borealis At BOREALIS Foils are moving at high speeds (up to 48 m/min) Foils are fluttering Temperature not constant along path Accessiblity not always easy Page 17 RECENDT 2011 Günther Hannesschläger

18 Moving foils No need for scanning sample moving at high velocities Static OCT-system Mirror (not moving) OCT image Single point probing head Sample Page 18 RECENDT 2011 Günther Hannesschläger

19 Moving foils Simulation of moving foils: ( m/min) Page 19 RECENDT 2011 Günther Hannesschläger

20 Moving foils Simulation of moving foils Speed: 0.3 m/min 0.25 mm broad 6 m/min 5 mm broad 48 m/min 40 mm broad Page 20 RECENDT 2011 Günther Hannesschläger

21 In-line measurements Blown film extrusion line Hosokawa Alpine Up to 7 layers Materials: Polypropylene Polyethylene Adhesion layer polymer EVOH Speed: mm/s Overall thickness: µm Page 21 RECENDT 2011 Günther Hannesschläger

22 In-line measurements Installation of the in-line OCT system Page 22 RECENDT 2011 Günther Hannesschläger

23 In-line measurements Results of in-line measurements Single foil, 3 layers 100 µm thickness Single foil, 3 layers 200 µm thickness Double foil, 4 layers 100 µm thickness Page 23 RECENDT 2011 Günther Hannesschläger

24 Summary Multi-layered foils need parameter control Is OCT a suitable tool? Lab based experiments Simulation of measuring moving foils In-line measurements Optical Coherence Tomography suits the task: In-line Industrial environment Page 24 RECENDT 2011 Günther Hannesschläger

25 Thanks to the actual and former members of the OCT group Eva Breuer Elisabeth Leiss Michael Leitner Alexandra Nemeth Giselher Pfandler Robert Gahleitner Bettina Heise Attila Saghy Martin Scheiblhofer David Stifter Karin Wiesauer Martin Wurm to financial support from Page 25 RECENDT 2011 Günther Hannesschläger

26 Thanks for your attention Page 26 RECENDT 2011 Günther Hannesschläger