Coil Component Terminals with Controlled Crack Roughness
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Solution Overview
Problem
In the reflow process of coil components, variations in wettability due to non-precise breaking processes can cause the components to rotate or shift, leading to potential short circuits between metal terminals with narrow intervals, as the surface roughness and forms of cracks generated during separation affect soldering quality.
Innovation Solution
The coil component design includes first and second metal terminals with specific end surfaces, where the crack with higher surface roughness is positioned to minimize wettability variation, and extended portions facilitate solder fillet formation, ensuring stable alignment and reducing the likelihood of short circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If non-precise breaking process is used to separate metal terminals from lead frame, then manufacturing complexity is reduced, but wettability variation increases causing component rotation or shifting
Solution Approach 1:
The patent applies preliminary action by pre-forming cracks with controlled surface roughness on the metal terminals before the breaking process. These pre-formed cracks serve as stress concentration points that guide the breaking process to occur at predetermined locations, ensuring that even with non-precise breaking, the separation occurs in a controlled manner that maintains alignment precision while keeping the manufacturing process simple.
2Ease of operation
If metal terminals are aligned in direction orthogonal to central axial line, then mounting is simplified, but short circuit risk increases due to narrow intervals
Solution Approach 1:
The patent applies local quality by creating asymmetric crack patterns on specific metal terminals. The cracks are formed with different surface roughness characteristics on different terminals, particularly on those with narrow intervals. This local differentiation in crack properties creates variations in wettability that prevent simultaneous soldering of adjacent terminals, thereby preventing short circuits while maintaining the simplified orthogonal alignment for mounting.
3Ease of manufacture
If crack surface roughness varies, then separation is easier, but soldering quality deteriorates due to wettability variation
Solution Approach 1:
The patent applies parameter changes by deliberately controlling and standardizing the surface roughness parameter of cracks on specific metal terminals. Instead of allowing random surface roughness variation, the invention specifies particular roughness ranges for cracks on terminals with narrow intervals versus those without. This controlled parameter change ensures that wettability variation is sufficient to prevent short circuits during soldering, while maintaining adequate soldering quality through defined roughness parameters.
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 configuration reduces the influence of wettability variation in the reflow process, preventing the coil component from rotating or shifting, thereby minimizing the occurrence of short circuits among metal terminals.
Implementation Method 1
variations in wettability due to non-precise breaking processes can cause the components to rotate or shift
Data Source
AI summary
A coil component including a core, first metal terminals, second metal terminals and a wire. The first metal terminals and second metal terminals have mounting portions provided above the mounting surface and aligned above the mounting surface. One of the mounting portions of the first metal terminals has a first end surface facing one of the mounting portions of the second metal terminals and a second end surface other than the first end surface, and the first end surface has a chopped trace where surface roughness is higher than surface roughness of the second end surface.