<title>CO2 laser tailored blank welding: process monitoring</title>

Abstract Ultrasonic metal welding is one of the key technologies in manufacturing lithium batteries, and the welding quality directly determines the battery performance. Therefore, an online welding process monitoring system is critical in identifying abnormal welding processes, detecting defects, and improving battery quality. Traditionally, the peak welding power is used to indicate abnormal process signals in welding process monitoring systems. However, since various factors have complex impacts on the electric power signals of ultrasonic welding processes, the peak power is inadequate to detect different types of welding defects. Therefore, a signal pattern matching method is proposed in this study, which is based on the electric power signal during the entire welding process and thus is capable of identifying abnormal welding processes in various conditions. The proposed method adopts isometric transformation and homogenization as signal pretreatment methods, and Euclidean distance is used to calculate the similarity metric for signal matching. The effectiveness and robustness of the proposed method are experimentally validated under different abnormal welding conditions.

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Aluminum Tailored Blank Welding Using Laser Beam Shaping and Twin-Spot Optics

10.1115/imece2000-1904 ◽

2000 ◽

Author(s):

Rey Hsu ◽

Stefan Fliss ◽

Stefan Heinemann

Keyword(s):

Co2 Laser ◽

High Power ◽

Beam Shaping ◽

Laser Source ◽

Test Results ◽

Co2 Lasers ◽

Production Environment ◽

Tailor Welded Blanks ◽

Tailored Blanks ◽

Tailored Blank

Abstract The use of aluminum tailor welded blanks in the automotive industry continues to grow due to the fact that aluminum is lightweight and the characteristics of the tailor welded blanks. It has been found that welding of aluminum blanks with a CO2 laser is difficult but doable in a production environment. By using a high power CW Nd:YAG (Neodynium dopped Yittrium Aluminum Garnet) laser. It is possible to obtain sound results with a much wider process parameter window. However, currently, high power CO2 lasers (in the range of 8 kW) are still the dominate laser source in North America steel tailor welded blank companies. Will these lasers be able to weld aluminum tailored blanks if the demand for aluminum tailor welded blanks increases? This study employed twin spot and beam shaping methods to weld 1mm and 2 mm tailored blanks together using a high power (9 kW maximum) CO2 laser for both 5754-O and 6111-T4 alloys. The results show that high power CO2 lasers can be used to weld 5754-O and 6111-T4 aluminum alloys with very precise parameter settings. However, using beam shaping is more critical than using twin spot for 1 mm thick aluminum blanks. Once the correct parameters are applied for using beam shaping, the cup test results are better than using twin spot.

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On-Line Monitor for the CO2-Laser Welding Process

Laser in der Technik / Laser in Engineering ◽

10.1007/978-3-662-08251-5_109 ◽

1994 ◽

pp. 499-502

Author(s):

M. Jurca

Keyword(s):

Laser Welding ◽

Co2 Laser ◽

Welding Process ◽

On Line ◽

Laser Welding Process

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