Two-Stage Hot Tinning for Uniform Copper Wire Coating
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Solution Overview
Problem
Existing methods for producing tinned copper wires often result in uneven tin coatings, leading to reduced heat resistance and salt spray resistance due to 'thin coating' and 'skip coating' issues, which are not adequately addressed by current hot tinning processes.
Innovation Solution
A process involving sequential hot tinning treatments at different temperatures, with the first treatment at a temperature at least 38°C higher than the melting point of tin and the second at least 8°C higher, using a molten tin liquid with rare metals and phosphorus, and wind cooling to ensure uniformity and prevent oxidation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a single hot tinning treatment is used, then the production process is simple, but the tin coating is uneven with thin coating and skip coating
Solution Approach 1:
The single hot tinning process is divided into two sequential hot tinning treatments. The first treatment applies tin coating to the copper wire, and the second treatment reinforces and uniformizes the coating. This segmentation resolves the contradiction by maintaining process simplicity through sequential operations while achieving uniform coating quality that a single treatment cannot provide.
Solution Approach 2:
The first hot tinning treatment serves as a preliminary action that prepares the copper wire surface with an initial tin coating. This preliminary coating enables the second treatment to achieve uniform thickness and continuity, as the wire surface is already primed for optimal tin adhesion and distribution in the subsequent treatment.
2Reliability
If the tin layer is made thicker to protect large diameter wires, then the protection performance improves, but the uniformity of the tin layer becomes difficult to ensure
Solution Approach 1:
The coating process is segmented into two treatments, allowing the total required thickness to be distributed across both stages. The first treatment establishes a baseline coating, and the second treatment adds the remaining thickness while maintaining uniformity control, thus achieving both thick protective layers and consistent coating quality.
Solution Approach 2:
The patent employs parameter changes by conducting the two hot tinning treatments at different temperatures. The first treatment uses one temperature regime to establish initial coating, while the second treatment uses a different temperature regime to achieve uniform thick coating. This parameter variation enables control over coating thickness and uniformity simultaneously.
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 process achieves a uniform, thick, and continuous tin layer with improved heat and salt spray resistance, increased production speed, and extended service life of the molten tin liquid, while reducing energy consumption and preventing re-melting and oxidation.
Implementation Method 1
Although the copper wires will undergo surface activation treatment before hot tinning, defects on the surface of the copper wires are not completely eliminated
Implementation Method 2
The process of hot tinning on the copper wire is essentially a process of wetting and diffusion
Implementation Method 3
the process of hot tinning on the copper wire is essentially a process of wetting and diffusion, and it is also a process of flowing and crystallizing of the tin liquid to be solidified onto the surface of the copper wire
Implementation Method 4
it is also a process of flowing and crystallizing of the tin liquid to be solidified onto the surface of the copper wire
Implementation Method 5
liquid tin adheres to the surface of the copper wire and then is cooled and solidified in the air to complete the continuous tinning
Implementation Method 6
copper atoms diffuse into the tin liquid when copper wire is being hot tinning in the tin liquid, so with the prolongation of production time, the concentration of copper atoms in the tin bank will increase significantly
Implementation Method 7
liquid tin adheres to the surface of the copper wire and then is cooled and solidified in the air
Data Source
AI summary
Provided is a process for producing a tinned copper wire. The process comprises subjecting a copper wire sequentially to activation treatment, a first hot tinning treatment, a first cooling, a second hot tinning treatment, and a second cooling to obtain a tinned copper wire. The first hot tinning treatment is carried out at a first temperature and the second hot tinning treatment is carried out at a second temperature. The first temperature is higher than the second temperature. The first temperature is at least 38° C. higher than the melting point of tin. The second temperature is at least 8° C. higher than the melting point of tin.