Zinc-Plated Steel Casing for Press Welding Ground Terminals
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Solution Overview
Problem
The existing methods for joining a tin-plated copper-based ground terminal with a casing metal plate in electronic devices face issues due to the reaction between copper and tin, leading to a brittle Cu-Sn alloy, which results in electrode wear and reduced productivity.
Innovation Solution
A diffusion joint method is employed where a zinc-plated steel casing metal plate sandwiches the ground terminal, using electrodes that do not contact the terminal, preventing wear and allowing for efficient welding without the need for additional components or complex operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If pressing energization welding is used to join the ground terminal with the casing metal plate, then additional components are not needed, but the copper electrode reacts with tin-plated ground terminal causing electrode wear and reduced productivity
Solution Approach 1:
The patent introduces a zinc-plated steel casing metal plate as an intermediary material between the copper electrode and the tin-plated ground terminal. The zinc plating on the casing metal plate prevents direct contact between copper and tin, avoiding the formation of brittle Cu-Sn alloy and preventing electrode wear, thus maintaining high welding productivity without adding extra components to the joining structure.
Solution Approach 2:
The patent uses composite material structure where the casing metal plate consists of steel base material with zinc plating coating. This composite structure provides both mechanical strength from steel and protective function from zinc plating, preventing harmful chemical reaction between copper electrode and tin-plated ground terminal while enabling effective welding.
2Reliability
If screw fastening with spring washer is used to join the metal plate with the ground terminal, then safe grounding joint is established, but additional components and screwing operation are required
Solution Approach 1:
The patent replaces the mechanical screw fastening system with a welding-based joining method. By using pressing energization to create a metallurgical bond between the casing metal plate and ground terminal, the need for screws, spring washers, and manual screwing operations is eliminated, simplifying the joining structure while maintaining reliable electrical connection.
3Reliability
If soldering is used to join the casing metal plate with the ground terminal, then electrical connection is achieved, but solder and soldering operation by operator are required
Solution Approach 1:
The patent replaces the thermal soldering process with a solid-state welding process using pressing energization. This substitution eliminates the need for solder materials and complex soldering operations requiring operator skill, while achieving reliable electrical connection through direct metallurgical bonding between the casing metal plate and ground terminal.
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 reduces electrode wear, improves productivity by minimizing the need for frequent polishing or replacement, and ensures a strong, reliable electrical connection.
Implementation Method 1
a current is caused to flow through the two metal materials (hereinafter, this method is referred to as pressing energization)
Data Source
AI summary
An electronic device includes an inlet including a ground terminal having a first surface and a second surface opposite from the first surface, a first casing metal plate configured to hold the inlet and contacting the first surface of the ground terminal, and a second casing metal plate contacting the second surface of the ground terminal.