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What Welding Defects Are Caused by Improper Heating-Rate Settings When Welding Small-Size New-Energy Copper-Foil Flexible Connections with a Polymer Diffusion Welder?
Oct 15,2026
The foil of small-size new-energy copper-foil flexible connections is thin with small heat capacity. The heating-rate setting of the polymer diffusion welder affects copper-foil welding and produces welding defects.
I Welding Defects Caused by Excessively Fast Heating Rate
1.The workpiece inside and outside are heated out of sync; heat conduction in the inner layer is insufficient, producing local cold joints in the inner layer.
2.Residual gas and volatiles between layers cannot be expelled in time and are sealed in the copper-foil interlayer, forming bubbles and blisters.
3.Inconsistent thermal expansion causes large internal thermal stress, and warping and wrinkles appear during post-welding cooling.
4.Local heat impact is large; the graphite tooling suffers severe thermal shock and easily cracks and sheds debris, and impurities mix into the workpiece causing inclusions.
5.Local temperature is too high, the copper foil oxidizes, hindering atom diffusion.
II Welding Defects Caused by Excessively Slow Heating Rate
1.The workpiece stays in a high-temperature environment for a long time; copper-foil surface oxidation worsens, the oxide film blocks interlayer bonding, and large-area cold joints and delamination appear.
2.The high-temperature holding time is too long, the copper becomes brittle, and cracking easily occurs during bending.
3.Under continuous high temperature and pressure, the copper foil undergoes excessive deformation.
4.Auxiliary materials carbonize due to prolonged overheating, impurities remain at the welding interface, contact resistance increases, and bonding strength decreases.
III Main Triggers of Improper Heating-Rate Setting
1.Directly applying the heating process for large-size products without re-debugging for small workpieces.
2.Blindly accelerating or slowing the heating rate.
3.Aging of equipment heating components.
IV Improvement and Control Key Points
1.Adapt welding parameters
2.Pressure and heating cooperate with each other
3.Do good welding environment and incoming-material control
4.Do good equipment calibration and quality inspection
Wuxi Haifei Intelligent Equipment Co., Ltd. https://www.haifeiwelder.com/
Wuxi Haifei Intelligent Equipment Co., Ltd. has been focusing on the R&D and production of diffusion‑welding equipment for 17 years. The company has passed ISO9001 Quality Management System Certification, China Compulsory Certification (3C) and CE Certification. It is a National High‑tech Enterprise, a Specialized, Refined, Differential and Innovative Enterprise of Jiangsu Province, a Specialized, Refined, Differential and Innovative Enterprise of Wuxi, and a Gazelle Enterprise in the Southern Jiangsu National Self‑Dependent Innovation Demonstration Zone.
Should you be interested in our diffusion‑welding equipment, please contact us: 400‑0510‑750.
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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