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If the wall thickness of copper tubes deviates when sealing copper tubes on an ultrasonic tube sealing machine, what sealing problems may it cause?
Nov 11,2026
When an ultrasonic tube sealing machine seals copper tubes, the tube end is sealed by ultrasonic vibration together with clamping force. A wall thickness deviation may look like a mere incoming tolerance issue, but it can change the stress, deformation and interface bonding state at the sealing position, and thus bring various potential sealing risks.
I. Unstable sealing formation and insufficient contact on the sealing surface
1. Where the wall is thinner, the deformation after compression is larger, the sealing cross-section may not be full enough and local contact may be insufficient.
2. Where the wall is thicker, deformation is relatively difficult, the sealing indentation is shallower and the interface bonding may fall short of the requirement.
3. When the wall thickness of a single tube is uneven, the sealing geometry becomes asymmetric and the sealing band width may vary along its length.
II. Potential risk of cracks and splitting at the sealing position
1. The thin-wall area bears both ultrasonic vibration and clamping load, stress is relatively concentrated and microcracks may appear on the surface.
2. Stress accumulates at the wall thickness transition, and a notch or local splitting may appear after sealing.
3. A thin wall may reduce the effective load-bearing thickness, so the sealed part carries a relatively higher failure risk under later compression and bending.
III. Variation in appearance and assembly dimensions
1. Indentation depth differs, the flatness of the sealing end face becomes worse and appearance consistency may be affected.
2. The actual length of the sealed section fluctuates, which may disturb later assembly positioning and fixture fit.
3. Uneven tube end shrinkage creates an out-of-round outer diameter, and sticking may occur during assembly.
IV. Unstable bonding strength and airtightness
1. Uneven wall thickness may cause the sealing bonding strength to fluctuate, and the pass rate of the airtightness test may drop accordingly.
2. Some hidden defects may only appear gradually under holding pressure or vibration, with a risk of slow leakage.
3. Wall thickness tolerances differ between batches, so a single set of sealing parameters is relatively difficult to adapt stably.
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 ultrasonic tube sealing 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 ultrasonic tube sealing machines, please contact us: liuyiyu@jshaifei.com
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Wuxi HAIFEI Intelligent Equipment Co., Ltd.
Wuxi HAIFEI Welding Equipment Co., Ltd.
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