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Adjustment of Temperature, Pressure & Pressure Holding Sequence for Interlayer Delamination in Multi-Layer Copper Foil Flexible Connectors on Fully Automatic Copper Diffusion Welding Stations
Aug 11,2026
Interlayer peeling, layered cracking, edge delamination, hollow cold joints and easy peeling by hand frequently occur during multi-layer copper foil flexible connector production on full-automatic copper diffusion stations. Most defects stem from mismatched temperature, pressure and holding timing rather than insufficient parameters, which lead inadequate interlayer diffusion and unbalanced cooling stress causing delamination.
I Core Causes of Layer Separation
Multi-layer copper foil contains numerous interlayer gaps that trap air. Copper features high thermal conductivity, resulting in overheated surface and insufficient internal temperature. Improper parameter matching creates pseudo fusion: only the surface bonds while inner layers remain unwelded. After cooling, inconsistent shrinkage of each layer generates tensile stress that tears interlayer bonding and forms delamination.
II Temperature Parameter Adjustment
Instant high temperature seals surface gaps and locks air inside to form hollow layers, and also embrittles copper. Gradient heating is required: slow preheating to exhaust air, followed by constant temperature holding to allow heat penetration layer by layer for uniform interlayer diffusion. Excessively low temperature limits diffusion; overhigh temperature creates severe thermal stress, both causing delamination.
III Pressure Parameter Adjustment
Pressure mainly serves flattening and air exhaust instead of blind high pressure. Low-pressure pre-compression at early stage slowly levels foil and expels interlayer air without sealing gaps. Maintain medium constant pressure during welding to achieve tight lamination for molecular diffusion; excessive pressure squeezes and cracks copper, while pressure fluctuation triggers intermittent local cold joints.
IV Pressure Holding Sequence Adjustment
Most delamination results from incorrect timing. Copper foil is soft and unfixed at high temperature; releasing pressure and removing workpieces immediately creates tensile stress from uneven shrinkage and hidden interlayer separation. Maintain pressure throughout slow cooling until fully shaped before pressure relief & unloading. More copper layers require longer cooling holding time.
V Tuning Ideas for Different Delamination Defects
1.Low temperature & insufficient constant-temperature period: slightly raise temperature and extend holding time.
2.Inadequate pre-pressure & incomplete air exhaust: optimize low-pressure pre-compression process.
3.Pressure relief while hot: prolong slow cooling holding time under pressure.
4.Excess welding temperature: appropriately lower set value.
5.Fluctuating pressure & timing: fix stable pressure parameters and unified production rhythm.
VI Four-Stage Standard Welding Process
1.Low-pressure pre-compression for air exhaust: flatten copper foil and discharge interlayer air;
2.Gradient preheating & heating: penetrate heat layer by layer to avoid air trapping under sealed surface gaps;
3.Constant temperature & pressure diffusion: realize full interlayer fusion with stable thermal & mechanical conditions;
4.Slow cooling forming under pressure: relieve cooling stress to eliminate interlayer delamination.
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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