Frame Terminal Plating Structure to Suppress Granular Plating
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Solution Overview
Problem
Conventional electronic components, such as varistors, experience granular plating near the bent portion of the frame terminal due to reflow mounting, leading to potential short circuits due to low adhesion of the plating layer.
Innovation Solution
The electronic component design includes a frame terminal with a thicker plating layer at the bent portion after heat treatment, which is bent along the exterior body's side surface, ensuring the plating layer can spread and adhere without cracking during reflow heating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the frame terminal is bent along the exterior body during mounting, then the electrical connection is established, but granular plating occurs near the bent portion due to plating layer cracking and falling off
Solution Approach 1:
The frame terminal is bent before the plating process. This preliminary bending action ensures that the bent portion does not crack during subsequent plating and reflow heating, preventing granular plating formation and maintaining plating layer integrity throughout the manufacturing and mounting processes.
Solution Approach 2:
The patent changes the sequence of operations by performing bending before plating rather than after. This parameter change in process sequence prevents the plating layer from cracking during bending, thereby eliminating the root cause of granular plating and improving adhesion reliability.
2Ease of manufacture
If the plating layer is applied before bending, then the frame terminal can be easily formed, but the plating layer cracks and falls off during reflow heating
Solution Approach 1:
The frame terminal is bent before the plating process. This preliminary bending action ensures that the bent portion does not crack during subsequent plating and reflow heating, preventing granular plating formation and maintaining plating layer integrity throughout the manufacturing and mounting processes.
Solution Approach 2:
The patent inverts the conventional sequence by bending the frame terminal before plating instead of after. This reversal prevents plating layer cracking during bending operations, maintaining manufacturing precision while preserving ease of frame terminal formation.
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 design effectively suppresses granular plating and subsequent short circuits by ensuring the plating layer's integrity and adhesion during mounting, enhancing reliability and preventing board failures.
Implementation Method 1
the electric element and the frame terminal covered with the exterior body are subjected to heat treatment at a temperature equal to or greater than a melting point of the plating layer
Data Source
AI summary
The occurrence of granular plating due to reflow heating during mounting is suppressed. An electronic component includes an electric element, a frame terminal, and an exterior body. The frame terminal includes a plating layer on a surface of the frame terminal, and is electrically connected to the electric element. The exterior body covers the electric element and a part of the frame terminal. The frame terminal includes a covered portion, and an exposed portion exposed from the side surface of the exterior body. The exposed portion includes a first bent portion where the frame terminal is bent along the side surface, and a first extension portion extending from the first bent portion toward the bottom surface of the exterior body. The plating layer near the first bent portion of the first extension portion has a thickness greater than a thickness of the plating layer in the covered portion.