Conductive Terminal Structure to Reduce Solder Tin Cracking
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Solution Overview
Problem
Existing electrical connectors for chip modules and printed circuit boards face a high risk of tin cracking due to high stiffness, which compromises the reliability and service life of the connection.
Innovation Solution
The design includes an insulating housing with terminals featuring a base, an elastic arm, and a soldering portion, where the through hole configuration reduces terminal rigidity by increasing the distance between the upper and lower edges, and incorporating retaining protrusions and gaps to enhance stability and deformation space, thereby reducing the risk of tin cracking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the distance from the base to the tin-containing hole is shortened in the upper and lower direction, then the stiffness coefficient of the terminal increases, but the risk of tin cracking increases
Solution Approach 1:
The through hole is positioned asymmetrically within the base, with its upper edge located at a greater distance from the upper edge of the base than the lower edge is from the lower edge of the base. This asymmetric positioning creates unequal moment arms that balance the stiffness requirements while reducing stress concentration on the soldering portion, thereby preventing tin cracking.
Solution Approach 2:
The invention changes the geometric parameters of the through hole positioning, specifically setting the first distance (from upper edge of through hole to upper edge of base) greater than the second distance (from lower edge of through hole to lower edge of base). This parameter adjustment optimizes the distribution of mechanical stress and maintains appropriate stiffness while reducing the risk of tin cracking.
2Ease of manufacture
If the terminal structure is simplified for easier manufacture, then the manufacturing cost decreases, but the stability after soldering may be compromised
Solution Approach 1:
The terminal is divided into distinct functional segments: a base portion with the through hole for positioning and structural support, a soldering portion for electrical connection, and retaining portions for mechanical fixation. This segmentation allows each part to be optimized independently for its specific function while maintaining overall manufacturing simplicity.
Solution Approach 2:
Different regions of the terminal are given different structural characteristics tailored to their specific functions. The base has a through hole for positioning, the soldering portion has specific geometry for reliable solder joint formation, and the retaining portions have features for secure mounting. This local optimization ensures both ease of manufacture and high reliability.
Data Source
AI summary
An electrical connector includes an insulating housing having an upper surface, a lower surface, and plural terminal holes penetrating the upper surface and lower surface; and plural conductive terminals retained in the insulating housing and including a base, an elastic arm extending upwardly from an upper edge of the base, and a soldering portion extending downwardly from a lower edge of the base, wherein each transverse side of the base has a retaining protrusion fixed to the insulating housing, the base includes a through hole having an upper edge, a lower edge, and two opposite side edges, a first distance between the upper edge of the through hole and the upper edge of the base is greater than a second distance between the lower edge of the through hole and the lower edge of the base.