Spot Welding Joint Geometry for Adhesive Gap Prevention
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Solution Overview
Problem
In spot welding, insufficient contact between panels can lead to welding failures and undesirable phenomena like explosions due to current flow through non-target areas, especially when a viscous material like weld bond is present, causing gaps and reducing product accuracy.
Innovation Solution
A spot welding method and apparatus that form a protrusion on one panel and a recess on the other, allowing the protrusion to be inserted into the recess and held between electrodes, ensuring contact and preventing gaps, thereby maintaining electric conductivity and reducing welding failures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a viscous material like weld bond is applied between two panels, then bonding strength is improved, but the material may enter between welding-target parts and inhibit current application, causing welding failure
Solution Approach 1:
The protrusion and recess are formed in advance before welding, creating a mechanical interlocking structure that prevents viscous material from entering the welding interface. This preliminary structural preparation ensures both bonding strength and welding reliability by addressing the material intrusion problem before welding occurs.
Solution Approach 2:
The invention applies local quality by creating a protrusion at the welding-target part of one panel and a corresponding recess at the welding-target part of the other panel. This localized structural modification ensures precise contact at the welding interface while allowing viscous material to be excluded from the critical welding zone, thereby maintaining both bonding strength and welding reliability.
2Reliability
If panels are pressed together to ensure contact at welding-target parts, then welding reliability is improved, but gaps may form when viscous material is present, reducing product accuracy
Solution Approach 1:
The protrusion and recess structures are formed preliminarily to establish precise geometric relationships between panels. This pre-formed interlocking structure ensures accurate positioning and contact at welding-target parts without gaps, even when viscous material is present, thereby maintaining both welding reliability and manufacturing precision.
Solution Approach 2:
The invention uses asymmetric protrusion and recess structures that are complementary in shape. This asymmetric design ensures precise fit and contact at the welding interface, preventing gaps and ensuring accurate panel alignment, which maintains both welding reliability and product accuracy.
3Productivity
If current is applied between electrodes to weld panels, then welding speed is improved, but current may flow through non-target parts causing explosions
Solution Approach 1:
The protrusion and recess create a localized contact interface at the welding-target parts, concentrating current flow through the intended path. This localized geometric feature ensures current is confined to the target area, preventing current from flowing through non-target parts and causing explosions, while maintaining efficient welding speed.
Solution Approach 2:
The protrusion and recess structure performs preliminary anti-action by preventing viscous material from entering the welding interface and ensuring proper panel contact before current application. This pre-prepared interface configuration prevents harmful current paths, eliminating explosion risk while maintaining welding productivity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach ensures consistent electric conductivity at welding-target parts, preventing welding failures and maintaining product accuracy by ensuring the protrusion and recess are in contact, even when a viscous adhesive is used, and allows for efficient production with reduced equipment costs.
Implementation Method 1
forming a protrusion on a surface facing the second panel, at a welding-target part of the first panel; forming a recess on a surface facing the protrusion, at a welding-target part of the second panel, such that the recess has a depth that allows a top of the protrusion to come into contact with a bottom of the recess
Implementation Method 2
welding two panels, which are held between a pair of electrodes, by applying a current between the electrodes
Implementation Method 3
resistance welding that involves applying a large current to overlapping panels and welding the panels together by the generated heat
Implementation Method 4
overlapping panels are held between a pair of electrodes and are then pressurized to be in contact with each other at welding-target parts
Data Source
AI summary
A spot welding method for welding a first panel and a second panel by applying a current between a pair of electrodes in pairs in a state in which the first panel and the second panel overlap one another and are held by the electrodes includes: forming a protrusion on a surface facing the second panel, at a welding-target part of the first panel; forming a recess on a surface facing the protrusion, at a welding-target part of the second panel, such that the recess has a depth that allows a top of the protrusion to come into contact with a bottom of the recess; and holding the welding-target part of the first panel and the welding-target part of the second panel between the electrodes, in a state in which the protrusion is inserted in the recess and applying the current between the electrodes.