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Why Do Aluminium Flexible Connections Welded by Aluminium Foil Diffusion Welding Machines Show Delamination and Blistering?
Nov 07,2026
Aluminium foil diffusion welding is mainly used for products such as aluminium flexible connections and laminated aluminium foil busbars. Delamination and blistering are common defects. On some workpieces the appearance looks intact, but the layers have already separated after peeling; the causes are concentrated in the following four aspects.
I. Insufficient Pre-treatment
1. Oxide film, rolling oil and dust remain on the aluminium foil surface, forming an isolating layer between layers and hindering atomic diffusion.
2. Cleaning or grinding is not thorough enough, so oil and oxide residues remain, and an effective metallurgical bond is hard to form at the interface.
3. After pre-treatment the foils are left for too long, an oxide film re-forms between layers, and the diffusion conditions deteriorate.
II. Mismatched Parameters
1. The pressure is too low or unevenly distributed, the layers are not tightly fitted and gaps remain.
2. The temperature is too low and the holding time insufficient, so diffusion is inadequate and the interface is only a mechanical fit.
3. Temperature, pressure and holding time are not set up as a process window matched to the number of layers and thickness.
III. Tooling and Equipment Factors
1. Poor parallelism of the pressure plates and ageing of the insulation layer cause uneven temperature and pressure distribution.
2. Temperature measurement deviation makes the interface temperature drift from the process window; the tooling lacks locating stops, so the stacked sheets are unstable in position.
IV. Incoming Material and Storage Factors
1. Incoming material is oxidised or damp, and layer misalignment and burrs are not controlled, which affects the fit between layers.
V. Solutions
1. Standardise pre-treatment: remove oil and oxide film by chemical cleaning or grinding, and complete welding within the specified time limit.
2. Establish a process window: determine temperature, pressure and holding time by tests according to the number of layers and thickness; keep the pressure uniform and do not release pressure prematurely during the holding and cooling stage.
3. Tooling maintenance: regularly check the parallelism and flatness of the pressure plates, calibrate the temperature sensors, and add locating stops.
4. Improve inspection: add peel, DC resistance and bend tests, and trace defective parts back through pre-treatment records and parameter curves.
Wuxi Haifei Intelligent Equipment Co., Ltd. official website: https://www.haifeiwelder.com/
Wuxi Haifei Intelligent Equipment Co., Ltd. has been dedicated to the research and production of diffusion welding machines for 17 years. The company has passed the ISO9001 quality management system certification, the national 3C certification and the CE certification. It is a national high-tech enterprise, a Specialized, Refined, Distinctive and Innovative enterprise of Jiangsu Province, a Specialized, Refined, Distinctive and Innovative enterprise of Wuxi City, and a Gazelle enterprise of the Southern Jiangsu National Independent Innovation Demonstration Zone. If you are interested in our diffusion welding machines, please contact us at liuyiyu@jshaifei.com.
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Wuxi HAIFEI Intelligent Equipment Co., Ltd.
Wuxi HAIFEI Welding Equipment Co., Ltd.
Add: 28 Shuiyun Road, Yuecheng, Jiangyin, Jiangsu Province, China. (Postal Code: 214404)
Mobile: +86 18915302352
Email: wushijie@jshaifei.com