Precious Metal Switch Contact Plating and Etching Process
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Solution Overview
Problem
Existing methods for preparing switch contact components with precious metal plating face limitations in achieving sufficient dust and oil stain resistance due to restricted plating thickness and uneven edge control, leading to potential increases in contact resistance and conductivity issues.
Innovation Solution
A method involving plating masking, precious metal plating, and etching, where a solvent-dissolvable or alkaline-resistant plating mask is printed on a base metal substrate, followed by electroplating or electroless plating, and subsequent etching with cupric chloride or ferric chloride solutions to create protruding precious metal surfaces, allowing for controlled thickness and improved durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If printed plating mask is used for partial gold plating, then gold consumption is reduced, but plating thickness is limited to less than twenty microns
Solution Approach 1:
The patent applies preliminary action by first forming a thick plating mask layer (5-20 microns) through screen printing before performing the plating process. This pre-formed thick mask layer serves as the foundation for achieving the desired thick plating results, allowing the precious metal plating to extend beyond the mask edges and create protrusions that achieve thicknesses exceeding twenty microns while still using the mask for pattern definition and gold consumption reduction
2Ease of manufacture
If printed plating mask is used, then partial plating is achieved, but plating edge perpendicularity and thickness uniformity are difficult to control
Solution Approach 1:
The patent applies inversion by reversing the traditional approach where the mask defines the exact plating boundary. Instead, the mask serves as a template that guides plating, but the plating is intentionally allowed to extend beyond the mask edges. The mask is removed after plating, leaving the protruding plating structure. This inverted approach transforms the mask from a strict boundary definition tool into a pattern-guiding template, solving the edge perpendicularity issue while maintaining partial plating capabilities
Solution Approach 2:
The patent applies parameter changes by modifying the plating process parameters to achieve thicker plating deposits. By adjusting plating time, current density, and bath composition, the process enables deposition of plating layers that exceed the mask thickness, creating the desired protruding structures with controlled thickness and improved edge geometry
3Loss of substance
If thin plating layer is used to reduce cost, then precious metal consumption is reduced, but dust and oil stain resistance deteriorate
Solution Approach 1:
The patent applies dimensionality change by transitioning from thin二维 plating layers to three-dimensional protruding plating structures. The plating is designed to extend vertically beyond the substrate surface, creating convex dots, stripes, or lattices with heights exceeding twenty microns. This vertical dimension provides dust and oil stain resistance through physical protrusion that prevents particle accumulation, while the base metal substrate provides structural support, allowing reduced precious metal volume compared to traditional thick uniform plating
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
The method enhances dust and oil stain resistance, ensures stable conductive properties, and extends the service life of switch contacts while optimizing the use of precious metals by achieving thicker, more protruded plating layers, thus improving reliability and reducing material costs.
Implementation Method 1
a solvent-dissolvable or alkaline-resistant plating mask is printed on a base metal substrate
Implementation Method 2
a solvent-dissolvable or alkaline-resistant plating mask is printed on a base metal substrate
Implementation Method 3
followed by electroplating or electroless plating
Implementation Method 4
followed by electroplating or electroless plating
Implementation Method 5
subsequent etching with cupric chloride or ferric chloride solutions to create protruding precious metal surfaces
Data Source
AI summary
This invention discloses a preparation method for precious metal switching contact components by means of plating masking, plating and etching processes. The plating masking process is performed by using a plating mask ink with or without a photo exposure machine. Plating of precious metals is performed by electroless plating or electro plating methods. Etching is carried out with etching solutions containing weak organic acids, weak inorganic acids or acidic buffering agents. Improvement of the etched surface gloss and prevention of the side etching are realized with the sulfur-contained compounds. The dust- and oil stain-resistances of the switch contacts are improved by increasing the etching depth. The switch contacts made by this invention are featured with the advantages of good reliability, good resistance to dust and oil stain, short contact bounce time, long service life, low cost of raw materials and so on.