Rhenium Tungsten Wire Surface Layer for Breakage-Free Drawing
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Solution Overview
Problem
Existing tungsten wires, particularly those with a small diameter, face issues such as breakage during wire drawing due to die marks and non-uniform deformation, leading to reduced yield and increased processing costs.
Innovation Solution
A tungsten wire alloy containing rhenium (Re) with a controlled mixture of carbon (C) and oxygen (O) on its surface, with a specific ratio of mixture thickness to wire diameter (A/B) ranging from 0.3% to 0.8%, ensuring uniform deformation and reducing die marks and breakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If wire diameter is reduced to increase pin density, then productivity and inspection capability are improved, but wire breakage and die marks increase significantly
Solution Approach 1:
The patent applies parameter changes by controlling the ratio of mixture layer thickness to wire diameter (A/B) within 0.05 to 2.0, and adjusting the carbon-to-oxygen ratio in the surface mixture. These parameter optimizations prevent wire breakage during drawing while enabling production of ultra-fine wires with diameters of 0.02 mm or less, thereby increasing pin density without sacrificing reliability
Solution Approach 2:
The patent creates a composite structure with a tungsten core and a surface mixture layer containing carbon and oxygen. This composite material design, where the surface layer composition is carefully controlled, prevents die marks and breakage during wire drawing, enabling reliable production of ultra-fine wires for high-density probe cards
2Productivity
If wire diameter is reduced to increase pin density, then productivity and inspection capability are improved, but die marks and surface defects increase
Solution Approach 1:
The patent controls the A/B ratio (mixture layer thickness to wire diameter) between 0.05 and 2.0, and optimizes the carbon-to-oxygen ratio in the surface mixture. These parameter adjustments eliminate die marks and surface defects during wire drawing, achieving excellent surface quality on ultra-fine wires with diameters of 0.02 mm or less
Solution Approach 2:
The patent converts the potentially harmful effect of surface mixture into a beneficial protective layer. By controlling the carbon and oxygen composition in the surface mixture, the previously problematic surface layer becomes protective against die marks and surface defects, enabling high-precision manufacturing of ultra-fine wires
3Ease of manufacture
If number of recrystallizations is increased to improve workability, then wire drawing becomes easier, but processing time and cost increase
Solution Approach 1:
The patent changes the approach from controlling recrystallization次数 to controlling surface composition parameters (A/B ratio and C/O ratio). This parameter shift improves workability during wire drawing without requiring multiple recrystallization cycles, significantly reducing processing time and cost while maintaining ease of manufacture
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 solution effectively suppresses wire breakage and die marks, enhancing yield and reducing defects in the wire drawing process, making it suitable for applications like probe pins and high-temperature thermocouples.
Implementation Method 1
it has been found that breakage in wire drawing and appearance of die marks can be suppressed by electrolysis or the like performed on a W wire for wire drawing
Data Source
AI summary
A tungsten wire according to an embodiment is a tungsten wire made of a W alloy containing rhenium, and includes a mixture on at least a part of a surface thereof, the mixture contains W, C, and O as constituent elements, and taking a radial cross-sectional thickness of the mixture as A mm and a diameter of the tungsten wire as B mm, an average value of a ratio A/B of A to B is 0.3% to 0.8%.