Characterization of a chromatic confocal displacement sensor integrated with an optical laser head

Zakrzewski, A.; Jurewicz, Piotr; Koruba, Piotr; Ćwikła, Michał; Reiner, Jacek

doi:10.1364/ao.421382

Cited by 7 publications

(4 citation statements)

References 28 publications

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“…In order to determine the distance (L) between the laser head nozzle (LHN) and the substrate material (S), an optical system developed by the authors was used ( Figure 1 ). Its detailed description, in terms of operating principle, parameters, and functionality, has been presented in previous publications [ 21 , 22 ]. In brief, the optical system is a modified version of the chromatic confocal sensor (CCS), which is commonly used as a stand-alone displacement sensor.…”

Section: Methodsmentioning

confidence: 99%

“…The developed LICCS system has an accuracy of 0.035 mm for the reference material (silver mirror) determined in accordance with the standard [ 25 ]. The accuracy value consists of trueness (the maximal difference between the measured sample position and the value derived from the calibration curve) and precision components (standard deviation of the error for approaching 0 mm displacement point) [ 21 ]. However, for the steel substrate, the average accuracy obtained is much higher, i.e., 0.09 mm and it is dependent on the surface quality of the sample.…”

Section: Methodsmentioning

confidence: 99%

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Online Correction of Laser Head Nozzle Position for Laser Metal Deposition Using a Chromatic Confocal Displacement System

Koruba

Iskierka

Poskart

et al. 2023

Sensors

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The stability and repeatability of laser metal deposition is particularly important when processing multiple layers or depositing material on complex component surfaces, and requires the use of process parameter control including the stand-off distance between the laser head and the substrate. The system proposed in this paper for correcting the stand-off parameter is based on a chromatic confocal sensor integrated into a laser head. Then, the spectral signal acquired from the measurement system is processed by using the developed application to compensate for the movement of an additional axis of the kinematic system. This study used an independent verification system based on the digital image correlation method. The validation tests were carried out using the system for correcting the stand-off parameter with different control algorithms and given motion trajectories and substrate materials. The results demonstrate that the developed system can be useful for laser metal deposition.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Online Correction of Laser Head Nozzle Position for Laser Metal Deposition Using a Chromatic Confocal Displacement System

Koruba

Iskierka

Poskart

et al. 2023

Sensors

Self Cite

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“…At present, to fulfill the increasingly high requirements for sensors in various precision measurement fields, researchers have improved the chromatic confocal sensors from different aspects, such as increasing the measurement speed [12,13], expanding the measurement range [14,15], and improving the measurement accuracy [16,17]. In addition, they can also be used in more measurement scenarios [18,19].…”

Section: Introductionmentioning

confidence: 99%

Compact chromatic confocal sensor for displacement and thickness measurements

Liu¹,

Lü²,

Liu³

et al. 2023

Meas. Sci. Technol.

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Chromatic confocal sensor is widely used in various precision measurement fields due to its advantages of high measurement accuracy, fast response speed and good stability. Different from the traditional fiber-coupled structure, we propose an integrated compact chromatic confocal sensing system that allows to overcome the device integrating constraints met in industrial environments. Aiming at the distortion of the peak waveform caused by the inconsistent spectral response of the system and to accurately extract the peak wavelength, a spectral characteristic compensation algorithm and a peak wavelength extraction method based on Gaussian curve fitting are proposed. Based on these, a segmented curve calibration algorithm is put forward to achieve accurate mapping between peak wavelength and position. For the thickness measurement of transparent objects, a simple thickness measurement model and its calibration procedure are proposed, which do not need to obtain prior parameters such as incident angle or refractive index. Finally, the performance of the proposed sensing system is tested by displacement measurement experiment and thickness measurement experiment. The experimental results show that the RMSE of displacement measurement is less than 0.1μm, and the RMSE of thickness measurement is less than 1μm, which verifies the effectiveness and feasibility of the proposed sensing system.

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“…Confocal spectral sensor [1,2] is a very important part of non-contact measurement of high-end precision instruments with rapid development in China. The spectral confocal sensor uses the linear one-to-one correspondence between different focusing distances and wavelengths established by the optical dispersion objective lens and returns the different wavelengths to the spectrometer through a splitting prism according to the principle of optical path reversibility, which is decoded and analyzed to obtain the position information, and then obtains the measured value.…”

Section: Introductionmentioning

confidence: 99%

Design of dispersive objective lens for spectral confocal displacement sensor based on GRIN lens

liu

et al. 2023

AOPC 2022: Optical Spectroscopy and Imaging

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Spectral confocal technology uses chromatic aberration which is generated by a dispersion lens to detect surface shape. The axial dispersion generated by the dispersion lens will affect the measurement range of the whole spectral confocal displacement sensor. The refractive index of an axial GRIN (gradient index, GRIN) lens varies non-homogeneous along the axial direction and is constantly perpendicular to an optical axis of the plane. The paper explored the design of a dispersive objective lens for a spectral confocal displacement sensor based on the GRIN lens. Firstly, the optical power and axial dispersion models of the GRIN lens are established. The axial dispersion can be realized by focusing the light of different wavelengths at different positions of the optical axis. Secondly, based on the optic power and dispersion function of the GRIN lens, the refractive index distribution of the GRIN lens and the simulation design of the dispersive objective lens is obtained by using MATLAB and ZEMAX software respectively. Finally, the GRIN dispersive objective lens is optimized by setting different merit function operands. The experimental results show that the axial GRIN lens can achieve a focal shift of 1130μm within the wavelength range from 486nm to 656nm. Moreover, the linearity of the lens behaves well. All the blur spot is much smaller than the airy spot. The lens has well-focused as well as high-precision. The research results provide a reference and theoretical basis for the application of the GRIN lens in spectral confocal technology.

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Characterization of a chromatic confocal displacement sensor integrated with an optical laser head

Cited by 7 publications

References 28 publications

Online Correction of Laser Head Nozzle Position for Laser Metal Deposition Using a Chromatic Confocal Displacement System

Online Correction of Laser Head Nozzle Position for Laser Metal Deposition Using a Chromatic Confocal Displacement System

Compact chromatic confocal sensor for displacement and thickness measurements

Design of dispersive objective lens for spectral confocal displacement sensor based on GRIN lens

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