Abbreviation (ISO4): Journal of Materials Engineering
Editor in chief: Xiangbao CHEN
Journal of Materials Engineering >
Vision detection and feature extraction of molten pool behavior in powder laser cladding
Received date: 2022-10-17
Revised date: 2023-08-14
Online published: 2024-03-10
Molten pool monitoring is the basis of forming process optimization, playing a pivotal role in improving the formation quality. A machine vision monitoring system was set up for the laser cladding process. Based on the OpenCV software library, a method combining K-means image segmentation and dual threshold Otsu image segmentation was proposed, which realizes the accurate distinction between molten pool and plume with the accuracy of extracting geometric features of molten pool contour up to 95%. By designing an orthogonal experiment of laser cladding Ti-6Al-4V metal powder, typical cladding samples were selected to analyze the width and shape change of the weld pool in time domain, obtaining the fluctuation rule of the weld pool of the cladding layer. The results show that the fluctuation frequency and amplitude of the molten pool are affected by the process parameters and their combinations, and gradually stabilize with the progress of the cladding. Abnormal fluctuations in the molten pool during the cladding process are conducive to the positioning and identification of cladding defects, helping to optimize process routes.
Fangyu DONG , Yongxiong CHEN , Lingchao KONG , Xiubing LIANG , Kaixin WANG . Vision detection and feature extraction of molten pool behavior in powder laser cladding[J]. Journal of Materials Engineering, 2023 , 51(11) : 197 -204 . DOI: 10.11868/j.issn.1001-4381.2022.000865
表1 Ti6Al4V粉末化学成分(质量分数/%)Table 1 Chemical compositions of Ti6Al4V powder (mass fraction/%) |
Al | V | Fe | C | H | Ti |
---|---|---|---|---|---|
6.36 | 4.01 | 0.18 | 0.01 | 0.002 | Bal |
表2 正交实验参数Table 2 Parameters of orthogonal experiments |
Level | Laser power(A)/W | Scanning speed(B)/(mm∙s-1) | Powder feedingrate(C)/(g∙min-1) | Spot diameter(D)/mm |
---|---|---|---|---|
1 | 900 | 5 | 1.89 | 2.0 |
2 | 950 | 6 | 2.58 | 2.1 |
3 | 1000 | 7 | 3.22 | 2.3 |
4 | 1050 | 8 | 3.82 | 2.6 |
5 | 1100 | 9 | 4.48 | 3.0 |
图8 图像处理前后的熔池图像 (a)熔池原图像;(b)处理后的熔池图像Fig.8 Images of molten pool before and after processing (a)original view of molten pool;(b)molten pool after processing |
表3 实验结果及熔池图像处理结果分析Table 3 Experimental results and analysis of molten pool image processing results |
Parameter | w/mm | w 1/mm | P/% | Parameter | w/mm | w 1/mm | P/% | Parameter | w/mm | w 1/mm | P/% |
---|---|---|---|---|---|---|---|---|---|---|---|
A 1 B 1 C 5 D 5 | 1.39 | 1.34 | 96.4 | A 2 B 5 C 3 D 5 | 1.16 | 1.17 | 99.1 | A 4 B 3 C 4 D 5 | 1.17 | 1.14 | 97.4 |
A 1 B 2 C 3 D 2 | 1.42 | 1.41 | 99.3 | A 3 B 1 C 2 D 4 | 1.49 | 1.46 | 98.0 | A 4 B 4 C 2 D 2 | 1.14 | 1.17 | 97.4 |
A 1 B 3 C 1 D 4 | 1.14 | 1.11 | 97.4 | A 3 B 2 C 5 D 1 | 1.43 | 1.53 | 93.0 | A 4 B 5 C 5 D 4 | 1.18 | 1.20 | 98.3 |
A 1 B 4 C 4 D 1 | 1.12 | 1.13 | 99.1 | A 3 B 3 C 3 D 3 | 1.24 | 1.21 | 97.6 | A 5 B 1 C 4 D 3 | 1.71 | 1.70 | 99.4 |
A 1 B 5 C 2 D 3 | 1.06 | 1.09 | 97.2 | A 3 B 4 C 1 D 5 | 1.07 | 1.06 | 99.1 | A 5 B 2 C 2 D 5 | 1.42 | 1.48 | 95.8 |
A 2 B 1 C 1 D 2 | 1.18 | 1.17 | 99.2 | A 3 B 5 C 4 D 2 | 1.22 | 1.19 | 97.5 | A 5 B 3 C 5 D 2 | 1.73 | 1.76 | 98.3 |
A 2 B 2 C 4 D 4 | 1.43 | 1.42 | 99.3 | A 4 B 1 C 3 D 1 | 1.49 | 1.53 | 97.3 | A 5 B 4 C 3 D 4 | 1.21 | 1.19 | 98.3 |
A 2 B 3 C 2 D 1 | 1.23 | 1.27 | 96.7 | A 4 B 2 C 1 D 3 | 1.47 | 1.52 | 96.6 | A 5 B 5 C 1 D 1 | 1.18 | 1.17 | 99.2 |
A 2 B 4 C 5 D 3 | 1.38 | 1.34 | 97.1 |
图10 扫描速率6 mm/s时熔池时域变化曲线(a)激光功率950 W;(b)激光功率1000 W;(c)激光功率1050 WFig.10 Time domain variation curves of molten pool at scanning speed of 6 mm/s (a)laser power 950 W;(b)laser power 1000 W;(c)laser power 1050 W |
图11 扫描速率7 mm/s时熔池时域变化曲线(a)激光功率950 W;(b)激光功率1000 W;(c)激光功率1050 WFig.11 Time domain variation curves of molten pool at scanning speed of 7 mm/s (a)laser power 950 W;(b)laser power 1000 W;(c)laser power 1050 W |
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