PCB Edge Connector Rounding to Reduce Contact Wear
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Solution Overview
Problem
Existing printed circuit board edge connector assemblies face issues with excessive wear of contact spring connectors due to sharp edges on the printed circuit board, requiring high insertion force, and risk of misalignment and corrosion, which increase manufacturing complexity and costs.
Innovation Solution
A printed circuit board assembly with a rounded edge portion and flexible circuit film covering, where contact pads are fabricated on the film to extend over the edge, reducing wear and insertion force while guiding contact spring connectors for precise alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a sharp edge is formed on the printed circuit board using a router bit, then the board can be precisely manufactured, but the contact spring connector experiences excessive wear and plating removal
Solution Approach 1:
The patent applies curvature by rounding the sharp edge of the printed circuit board contact pad to a curved surface with a specified radius of curvature. This rounded edge reduces stress concentration and prevents the contact spring connector from riding over a sharp edge, thereby minimizing wear and plating removal while maintaining manufacturing precision through controlled rounding processes
2Ease of operation
If the contact spring connector directly contacts the sharp edge of the printed circuit board, then insertion is straightforward, but high insertion force is required and misalignment may occur
Solution Approach 1:
The patent introduces an intermediary rounded edge surface between the contact spring connector and the sharp board edge. This rounded surface acts as a mediator that guides the contact spring connector during insertion, distributing the insertion force more evenly and preventing misalignment while reducing the peak force required compared to direct sharp edge contact
3Reliability
If gold and nickel plating is applied to minimize corrosion, then contact surface corrosion is reduced, but the plating is removed due to wear over time
Solution Approach 1:
The patent applies beforehand cushioning by pre-rounding the edge before plating application. The rounded geometry distributes contact pressure more evenly across the contact surface, preventing stress concentration that would otherwise lead to plating removal. This protective geometric feature is established before the plating is applied, cushioning the plating layer against excessive wear during subsequent mating operations
Data Source
AI summary
A printed circuit board assembly and method of assembly is provided for a printed circuit board having a top and bottom surface with at least one edge portion having a rounded surface extending from the top surface to a point below the top surface and at least one electrical contact pad located on the top surface and extending over the edge portion rounded surface to a point below the top surface.