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Troubleshooting for Detached Welds & Burst Defects in Nut Projection Welding by Medium Frequency Spot Welders
Jul 08,2026
Nut projection welding is a core process of medium frequency spot welders, widely used in automotive and construction machinery industries. Detached joints and burst failures frequently occur in mass production, severely lowering productivity and product quality. Corresponding solutions are as follows.
I. Core Defects & Root Causes
(1) Causes of Detached Welds
1.Unbalanced welding parameters: improper current and duration generate insufficient heat and fail to form sound nuggets.
2.Inadequate workpiece pre-treatment: residual oil and oxide films block heat transfer.
3.Worn electrodes or misaligned coaxiality; inaccurate fixture positioning leads to uneven heat distribution.
4.Unclean nut/sheet surfaces with interlayer gaps.
(2) Causes of Burst Defects
1.Out-of-control parameters: excessive current and prolonged welding cause extreme heat concentration.
2.Improper electrode pressure or faulty cooling system fails to dissipate heat promptly.
3.Mismatched nut material/specification with process; uncleaned oxide layers.
II. Targeted Solutions
(1) Pre-Work Preparation
1.Optimize parameters: adopt constant current mode, follow high-current short-time rule. Adjust current and pressure per nut size. Use dual pulse mode for galvanized steel: preheat first then fusion welding.
2.Workpiece pre-treatment: remove oil and oxide, screen qualified nuts and ensure zero-gap tight lamination between nuts and sheets.
3.Standardize electrodes & fixtures: select matching electrodes, grind/replace worn electrodes regularly and calibrate electrode coaxiality. Optimize fixtures to prevent workpiece shifting.
(2) In-Welding Process Control
1.Control welding cycle to avoid electrode overheating; match current and pressure to prevent excessive heat generation.
2.Upgrade cooling system for timely heat dissipation to stop nut/sheet overheating.
3.Monitor nugget appearance and adjust parameters instantly to eliminate detachment and bursts.
(3) Post-Work Assurance
1.Perform first article inspection before mass production and adjust processes accordingly.
2.Daily maintenance: regularly inspect cooling circuits and electrode conditions; calibrate machine precision periodically.
3.Standardize SOPs and strengthen operator training to reduce human error.
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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