Tin Plating Reflow Melting Oxidation Prevention
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Solution Overview
Problem
The existing methods for reflow melting of tin plating in electronic connectors face issues of uneven melting due to oxidation and contamination, leading to problems like shrinkage, porosity, and whisker growth, which are exacerbated by differential heat absorption and reaction with air oxygen, despite efforts to improve equipment settings and parameters.
Innovation Solution
A workpiece plating treatment method involving surface cleaning to remove oxides and dirt, followed by reflow melting using a reflow melting device, which includes steps to increase moisture content and form a protective film to ensure uniform melting and prevent oxidation during the process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If reflow melting is performed on oxidized tin plating, then the melting process can proceed, but the tin oxide inclusions cause uneven wetting and asynchronous melting resulting in shrinkage and porous bulging
Solution Approach 1:
The patent applies preliminary action by performing cleaning treatment before reflow melting to remove oxides and contaminants from the tin plating surface. This preliminary cleaning step ensures that the subsequent melting process occurs on a clean surface, preventing the formation of tin oxide inclusions that would cause uneven wetting and asynchronous melting.
Solution Approach 2:
The patent employs an inert atmosphere (nitrogen or other inert gas) during the reflow melting process to prevent oxidation of the tin plating. By maintaining an oxygen-free environment, the tin plating remains free from oxide formation during heating, ensuring uniform melting without shrinkage or porous bulging defects.
2Reliability
If inert gases are used for protection during reflow melting, then oxidation is prevented, but the process complexity and cost increase
Solution Approach 1:
The patent applies parameter changes by modifying the atmospheric composition parameter during reflow melting. By changing from ambient air to inert gas atmosphere, the oxidation prevention is achieved. This parameter change is integrated into the existing reflow melting process, allowing oxidation protection without requiring fundamentally new equipment or complex process changes.
3Adaptability or versatility
If different parts of the tin plating surface have different heat absorption rates, then the reflow melting can accommodate varying surface conditions, but asynchronous melting and cooling occur leading to shrinkage and porous bulges
Solution Approach 1:
The patent applies homogeneity by ensuring uniform surface conditions through cleaning treatment before reflow melting. By removing oxides and contaminants that would cause varying heat absorption rates, the entire tin plating surface achieves consistent thermal properties. This homogeneous surface condition ensures synchronous melting and cooling across all parts of the plating, preventing shrinkage and porous bulge 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
The method achieves uniform and stable reflow melting of tin plating, reducing the risk of whisker growth and improving the mechanical properties of the plating layer, thereby enhancing the reliability of electronic connectors.
Implementation Method 1
remove a plurality of oxides and dirt on the outer surface of the outer plating layer
Implementation Method 2
reflow melting the outer plating layer of the workpiece using a reflow melting device
Implementation Method 3
reflow melting device...heat the outer plating layer to a temperature above the melting point
Implementation Method 4
form a protective film to ensure uniform melting and prevent oxidation during the process
Data Source
AI summary
A workpiece plating treatment method includes the steps of cleaning an outer surface of an outer plating layer of a workpiece to remove a plurality of oxides and dirt on the outer surface of the outer plating layer, and reflow melting the outer plating layer of the workpiece using a reflow melting device after the cleaning.