Melt pool monitoring in laser beam melting with two-wavelength holographic imaging

Piniard, Matthieu; Sorrente, Béatrice; Hug, G.; Picart, Pascal

doi:10.37188/lam.2022.011

Cited by 5 publications

(3 citation statements)

References 50 publications

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“…The floating hologram structure is divided into the reflection and transmission types, as shown in Figure 1. In Figure 1a, in the reflection type, a laser beam is irradiated by a laser generator, and the irradiated laser beam is incident on a beam splitter along the path of a [21]. The laser beam incident from a is split into 0 • and 90 • (θ q ) at c and b, respectively, and transmitted by a 45 • beam splitter [17].…”

Section: Analysis and Design Methodsmentioning

confidence: 99%

Design of the Floating Hologram Method with a Reverse Pyramid Type for CT and MR Diagnosis in Clinical Room

2022

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In the field of medical diagnosis, big data and three-dimensional (3D) imaging diagnosis technology are being applied due to the development of these technologies. Using radiology diagnosis methods, medical staff are increasing their understanding and ability to explain symptoms to patients, but they are experiencing difficulties due to communication problems. Therefore, if the medical staff shows the lesion by providing the patient with a 3D image, the understanding of the patient can be increased. This paper proposes the design of a system to produce an inverted pyramid-shaped floating holographic image to increase the patient’s understanding. The hologram system consists of an optical source generator and a beam mirror and utilizes a technology to plot an image using a 45° refraction angle of the beam of the optical source. Selected objects for observation were liver, colon, and lung, and to observe these tissues, a Computed Tomography (CT) image was input to the hologram system through the picture archiving and communication system (PACS), and the image was displayed. Tissues observed through the mirror can be observed from the left, right, front, and back with a 360° anterior view. Therefore, it is possible to observe at the desired position by the medical staff and the patient in the treatment room, and the image is large and clear, so it is very satisfying to observe. As a holographic imaging diagnostic system, it is expected that this study can be used in clinics, medical education rooms, and operating rooms in the future.

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Section: Analysis and Design Methodsmentioning

confidence: 99%

Design of the Floating Hologram Method with a Reverse Pyramid Type for CT and MR Diagnosis in Clinical Room

2022

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“…HI precisely measure micro and nanometer displacements [27][28][29][30], vibrations [31,32], refractive index and phase [33,34] and thus find applications in a wide range of processes. Hence, holographic interferometric techniques have been widely used for study and NDT applications including testing and quality control of industrial and scientific products [4,[22][23][24][35][36][37][38][39][40][41][42][43][44][45][46][47][48][49][50][51][52][53][54], space and avionic components [42][43][44][45], automotive components [45,46], machine tools [47,48] etc.…”

Section: Introductionmentioning

confidence: 99%

Emerging scientific and industrial applications of digital holography: an overview

Kumar,

Dwivedi

2023

Eng. Res. Express

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Holography is a technique to record and reconstruct three dimensional (3D) information without mandating lenses. Digital holography (DH) provides direct access to the complex amplitude of the reconstructed wavefront. This feature differentiates DH from other imaging techniques and enables it to provide quantitative information of the object under investigation. Advancements in technologies of digital image sensors, coherent sources, and computation algorithms and hardware, has paved the way of digital holographic systems for industrial applications. This work presents an overview of the scientific and industrial applications where DH can play an important role. Few of the applications of digital holographic systems in the industrial and scientific areas including microscopy, non-destructive testing, displays, environment, cloud and ocean studies are discussed.

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“…Machine tools have been measured by MWDH, where the depth of measured surface is in the micrometer range with standard deviation below 1µm [7]. Matthieu et al monitored melt pool during metal additive manufacturing by DWDH, where the depth measurement range reaches 100µm with phase noise's standard deviation of 1.01 rad [8]. However, the application of DWDH in the measurement of rough objects remains sparse.…”

Section: Introductionmentioning

confidence: 99%

3D Measurement of rough objects based on dual wavelength digital holography

Zhang¹,

Hou²,

Ma³

et al. 2023

International Conference on Optical and Photonic Engineering (icOPEN 2022)

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Traditional topography measurements for rough objects are usually based on point-contact scan. The way of pointcontact scan is usually not a high-efficient way to obtain data. Hence, in practice, only a few traces are measured which result in limited data. In order to obtain topography of sufficient amount of data, the demand for rapid noncontact measurement is increasing. In this work, we propose a dual wavelength digital holography (DWDH) measurement system with a synthetic wavelength of 51µm . We apply the DWDH system for 3D measurement of rougher surfaces and objects with a complex and small-size structure to further explore the measurement capability of DWDH. The proposed system enables the possibility to obtain the entire topography with millions of points of a rough surface in a single noncontact measurement. Firstly, we measure a cylinder workpiece of 10mm radius with a large roughness of Ra = 2.6µm which causes severe noise to measurement. The measured radius is 9.8099mm, which indicates a good accuracy. The mean standard deviation of all measured points is 1.08µm, which indicates a good repeatability and good anti-noise capability of the DWDH system. Then the proposed system is applied to measure the tooth surface of a gear of 1mm module and 18 teeth which has a complex and small-size structure. The measured surface shape agrees with the ideal gear tooth surface shape well. And the mean standard deviation of all measured points is 0.94µm , which also verifies its good repeatability. Our work presents the possibility of broader DWDH applications in industrial topography measurements.

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Melt pool monitoring in laser beam melting with two-wavelength holographic imaging

Cited by 5 publications

References 50 publications

Design of the Floating Hologram Method with a Reverse Pyramid Type for CT and MR Diagnosis in Clinical Room

Design of the Floating Hologram Method with a Reverse Pyramid Type for CT and MR Diagnosis in Clinical Room

Emerging scientific and industrial applications of digital holography: an overview

3D Measurement of rough objects based on dual wavelength digital holography

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