Dynamic, three-dimensional optical tracking of an ablative laser beam

2005 ◽  
Vol 32 (1) ◽  
pp. 209-220 ◽  
Author(s):  
Steven C. Gebhart ◽  
E. Duco Jansen ◽  
Robert L. Galloway
2003 ◽  
Author(s):  
Steven C. Gebhart ◽  
Robert L. Galloway, Jr. ◽  
E. Duco Jansen

2003 ◽  
Author(s):  
Steven C. Gebhart ◽  
Robert L. Galloway, Jr. ◽  
E. Duco Jansen

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yi Shu ◽  
Daniel Galles ◽  
Ottman A. Tertuliano ◽  
Brandon A. McWilliams ◽  
Nancy Yang ◽  
...  

AbstractThe study of microstructure evolution in additive manufacturing of metals would be aided by knowing the thermal history. Since temperature measurements beneath the surface are difficult, estimates are obtained from computational thermo-mechanical models calibrated against traces left in the sample revealed after etching, such as the trace of the melt pool boundary. Here we examine the question of how reliable thermal histories computed from a model that reproduces the melt pool trace are. To this end, we perform experiments in which one of two different laser beams moves with constant velocity and power over a substrate of 17-4PH SS or Ti-6Al-4V, with low enough power to avoid generating a keyhole. We find that thermal histories appear to be reliably computed provided that (a) the power density distribution of the laser beam over the substrate is well characterized, and (b) convective heat transport effects are accounted for. Poor control of the laser beam leads to potentially multiple three-dimensional melt pool shapes compatible with the melt pool trace, and therefore to multiple potential thermal histories. Ignoring convective effects leads to results that are inconsistent with experiments, even for the mild melt pools here.


2018 ◽  
Vol 23 (3) ◽  
pp. 1148-1158 ◽  
Author(s):  
Brahim Tamadazte ◽  
Rupert Renevier ◽  
Jean-Antoine Seon ◽  
Andrey V. Kudryavtsev ◽  
Nicolas Andreff

2001 ◽  
Vol 63 (3) ◽  
Author(s):  
Shi-Bing Liu ◽  
Ping-Qing Luo ◽  
Yong-Hui Zhang ◽  
Shao-Ping Zhu ◽  
Wei-Yan Zhang

2011 ◽  
Vol 35 (3) ◽  
pp. 308-312 ◽  
Author(s):  
Hai-Xiao Deng ◽  
Tang-Yu Lin ◽  
Jun Yan ◽  
Dong Wang ◽  
Zhi-Min Dai

Author(s):  
Eiichirou Tanaka ◽  
Yuta Kojima ◽  
Hiroki Yoshimi ◽  
Kazunari Okabe ◽  
Hitoshi Takebe ◽  
...  

We developed a new diagnostic method by using a laser beam. This method is as follows: A tooth surface is irradiated by the zonal laser beam from an oblique direction, and then the irradiated laser beam line is shifted along the surface of the tooth according to gear rotation. If the damage on the irradiated tooth surface exists, the voltage proportional to laser reflection increases. We developed the method to predict and make the reflection benchmark on the normal condition according to the gear surface. To make the benchmark of the diagnosis, the three dimensional basic-data map (x: irradiated angle, y: irradiated distance, z: reflection intensity) was created by measuring the gear only whose material, heat treatment, and roughness were same as the targeted gear. By using the equations of tooth profile and fillet curves calculated from the specifications of the targeted gear, the distance and angle relations between the laser sensor and the tooth surface can be derived. By using the three dimensional basic-data map, the benchmark can be created. The measured reflection data of the non-damage gear agreed well with the benchmark, therefore we can diagnose the various specification gears, if the targeted gear’s material, heat treatment, and roughness are same. Finally, by using the benchmark which was made by our developed method, we proposed a novel diagnosis method. The procedure of the method is as follows: 1) The benchmark is made from the targeted gear’s specifications. 2) To take into account the fluctuation of the benchmark line influenced by the roughness on the gear surface, normal condition area of the reflected data is defined in the range between −0.05 V and +0.05 V of the benchmark line. 3) The normal condition area and measured data is compared, if the measured data is deviated from the normal condition area, there is defined as the abnormal area possible to be damaged. To confirm the validity of this diagnosis method, the measured value of the damage area with caliper directly and calculated value from the method as mentioned above. The errors of the area and the location were within 20 %. Therefore, the effectiveness of the method using the benchmark data can be confirmed.


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