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In-line computational shear interferometry of insert molded micro parts for optical application


Micro injection moulding is a mass production of micro optics that offers the possibility of a high functional integration within a single micro part by insert moulding. Since the functionality of the micro parts depends on the homogeneity of the overmoulded polymer layer, a robust, accurate and fast metrology system is needed for a quantitative quality assessment. Here, we demonstrate an in-line metrology approach for the optical inspection of insert molded micro parts. In contrast to standard interferometers, the proposed system has low demands regarding the coherence of illumination. Thus, an LED light source can be used instead of a laser, reducing the cost and increasing the safety of the production platform. In addition, the system is robust against mechanical distortions, since it is based on a common path approach. These advantages make the system a good candidate that fulfills the needs in regard to the in-line inspection of insert molded micro parts. As an example of application, the proposed system is used to inspect a cannula with overmolded thermoplastic as a light sleeve providing illumination over a specific area of surgery.

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  1. Weber L, Ehrfeld W (1999) Mikroabformung: Ein bericht zu marktlage und entwicklungpotential. Kunststoffe 89(10):192– 202

    Google Scholar 

  2. Sha B, Dimov S, Griffiths C, Packianather M (2007) Investigation of micro-injection moulding: factors affecting the replication quality. J Mater Process Technol 183(2–3):284–296. doi:10.1016/j.jmatprotec.2006.10.019

    Article  Google Scholar 

  3. Chen S C, Chang Y, Chang Y P, Chen Y C, Tseng C Y (2009) Effect of cavity surface coating on mold temperature variation and the quality of injection molded parts. International Communications in Heat and Mass Transfer 36(10):1030–1035. doi:10.1016/j.icheatmasstransfer.2009.06.020

    Article  Google Scholar 

  4. Cheng K, Huo D (2013) Micro cutting: fundamentals and applications. Wiley, Chichester

    Book  Google Scholar 

  5. Lucchetta G, Bariani P (2010) Sustainable design of injection moulded parts by material intensity reduction. {CIRP} Annals - Manufacturing Technology 59(1):33–36. doi:10.1016/j.cirp.2010.03.092

    Article  Google Scholar 

  6. Griffiths C, Tosello G, Dimov S, Scholz S, Rees A, Whiteside B (2015) Characterisation of demoulding parameters in microinjection moulding. Microsyst Technol 21(8):1677–1690. doi:10.1007/s00542-014-2269-6

    Article  Google Scholar 

  7. Hansen H, Carneiro K, Haitjema H, Chiffre L D (2006) Dimensional micro and nano metrology. {CIRP} Annals - Manufacturing Technology 55(2):721–743. doi:10.1016/j.cirp.2006.10.005

    Article  Google Scholar 

  8. Yoshii M, Kuramoto H, Kato K (1994) Experimental study of transcription of minute width grooves in injection molding. Polym Eng Sci 34(15):1211–1218. doi:10.1002/pen.760341507

    Article  Google Scholar 

  9. Seebacher S, Osten W, Jüptner W P O (1998) Measuring shape and deformation of small objects using digital holography. Proceedings of the SPIE 3479:104–115. doi:10.1117/12.316439

    Article  Google Scholar 

  10. Kopylow C V, Bergmann R (2013) Optical metrology. In: Vollertsen F (ed) Forming, Micro Metal. Springer, pp 392–404

  11. Agour M, El-Farahaty K, Seisa E, Omar E, Sokkar T (2015) Single-shot digital holography for fast measuring optical properties of fibers. Appl Opt 54(28):E188–E195. doi:10.1364/AO.54.00E188

    Article  Google Scholar 

  12. Falldorf C, Osten S V, Kopylow C, Jüptner W (2009) Shearing interferometer based on the birefringent properties of a spatial light modulator. Opt Lett 34(18):2727–2729. doi:10.1364/OL.34.002727

    Article  Google Scholar 

  13. Falldorf C, Klattenhoff R, Gesierich A, Kopylow C V, Bergmann R (2009) Lateral shearing interferometer based on a spatial light modulator in the fourier plane. In: Osten M K W (ed) fringe 2009. Springer, pp 93–98

  14. Falldorf C, Agour M, Bergmann R B (2014) Advanced wave field sensing using computational shear interferometry. Proceedings of the SPIE 9204:92,040C–92,040C–9. doi:10.1117/12.2062814

    Article  Google Scholar 

  15. Falldorf C, Agour M, Bergmann R B (2015) Digital holography and quantitative phase contrast imaging using computational shear interferometry. Opt Eng 54(2):024,110. doi:10.1117/1.OE.54.2.024110

    Article  Google Scholar 

  16. Agour M, Riemer O, Flosky C, Meier A, Bergmann R B, Falldorf C (2016) Quantitative phase contrast imaging of microinjection molded parts using computational shear interferometry. IEEE Transactions on Industrial Informatics 12(4):1623–1630. doi:10.1109/TII.2015.2481704

    Article  Google Scholar 

  17. Falldorf C (2011) Measuring the complex amplitude of wave fields by means of shear interferometry. J Opt Soc Am A 28(8):1636–1647. doi:10.1364/JOSAA.28.001636

    Article  Google Scholar 

  18. Falldorf C, von Kopylow C, Bergmann R B (2013) Wave field sensing by means of computational shear interferometry. J Opt Soc Am A 30(10):1905–1912. doi:10.1364/JOSAA.30.001905

    Article  Google Scholar 

  19. Agour M, Falldorf C, Bergmann R B (2016) Shape measurements of microscopic objects using computational shear interferometry. Proceedings of the SPIE 9718:97,182M. doi:10.1117/12.2212910

    Article  Google Scholar 

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Correspondence to Mostafa Agour.

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Agour, M., Flosky, C., Riemer, O. et al. In-line computational shear interferometry of insert molded micro parts for optical application. Int J Adv Manuf Technol 91, 1671–1676 (2017).

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