Measurements of characteristic parameters of extremely small cogged wheels with low module by means of low-coherence interferometry

Anna Pakula; Slawomir Tomczewski; Andrzej Skalski; Dionizy Biało; Leszek Salbut

doi:10.1117/12.854916

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14 May 2010 Measurements of characteristic parameters of extremely small cogged wheels with low module by means of low-coherence interferometry

Anna Pakula, Slawomir Tomczewski, Andrzej Skalski, Dionizy Biało, Leszek Salbut

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Proceedings Volume 7718, Optical Micro- and Nanometrology III; 77180M (2010) https://doi.org/10.1117/12.854916
Event: SPIE Photonics Europe, 2010, Brussels, Belgium

Abstract

This paper presents novel application of Low Coherence Interferometry (LCI) in measurements of characteristic parameters as circular pitch, foot diameter, heads diameter, in extremely small cogged wheels (cogged wheel diameter lower than θ=3 mm and module m = 0.15) produced from metal and ceramics. The most interesting issue concerning small diameter cogged wheels occurs during their production. The characteristic parameters of the wheel depend strongly on the manufacturing process and while inspecting small diameter wheels the shrinkage during the cast varies with the slight change of fabrication process. In the paper the LCI interferometric Twyman - Green setup with pigtailed high power light emitting diode, for cogged wheels measurement, is described. Due to its relatively big field of view the whole wheel can be examined in one measurement, without the necessity of numerical stitching. For purposes of small cogged wheel's characteristic parameters measurement the special binarization algorithm was developed and successfully applied. At the end the results of measurement of heads and foot diameters of two cogged wheels obtained by proposed LCI setup are presented and compared with the results obtained by the commercial optical profiler. The results of examination of injection moulds used for fabrication of measured cogged wheels are also presented. Additionally, the value of cogged wheels shrinkage is calculated as a conclusion for obtained results. Proposed method is suitable for complex measurements of small diameter cogged wheels with low module especially when there are no measurements standards for such objects.

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Anna Pakula, Slawomir Tomczewski, Andrzej Skalski, Dionizy Biało, and Leszek Salbut "Measurements of characteristic parameters of extremely small cogged wheels with low module by means of low-coherence interferometry", Proc. SPIE 7718, Optical Micro- and Nanometrology III, 77180M (14 May 2010); https://doi.org/10.1117/12.854916

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