Ni-Ti Guide Wire Joint Structure for Higher Joining Strength
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Solution Overview
Problem
Existing guide wires face challenges in maintaining sufficient joining strength at the joint portion, leading to potential bending during intravascular use due to insufficient rigidity and torque transmission performance.
Innovation Solution
A guide wire is constructed with a first wire and a second wire made of nickel-titanium-based alloy, joined in a solid phase, with a specific crystal grain size distribution and frequency distribution to enhance joining strength, and a protruding portion is formed to improve rigidity and prevent bending.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If wires are joined in conventional manner, then manufacturing is simple, but joining strength is insufficient leading to bending risk
Solution Approach 1:
The patent applies parameter changes by controlling the crystal grain size distribution in the joint portion through specific solid-phase joining parameters (temperature, pressure, time). By optimizing these parameters, the crystal grain size is controlled to enhance joining strength without requiring complex structural modifications to the joint itself.
Solution Approach 2:
The patent utilizes composite material principles by creating a joint portion with a specific crystal grain structure that combines properties of both joined wires. The controlled crystal grain distribution creates a composite microstructure that provides superior joining strength compared to conventional joining methods.
2Reliability
If distal side has low flexural rigidity for vessel selectivity, then intravascular insertion safety improves, but torque transmission performance deteriorates
Solution Approach 1:
The patent applies local quality by creating a joint portion with specific crystal grain size distribution that has enhanced mechanical properties localized at the joint region. This allows the distal side to maintain low flexural rigidity for vessel selectivity while the joint portion has high joining strength for torque transmission.
Solution Approach 2:
The patent segments the guide wire into different functional zones: a distal side with low flexural rigidity for vessel navigation and a joint portion with optimized crystal grain structure for strong mechanical connection and torque transmission. This segmentation allows each zone to perform its specific function optimally.
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 improved joining strength and rigidity of the joint portion reduce the risk of bending, ensuring effective torque transmission and pushing performance during intravascular procedures.
Implementation Method 1
a first wire and a second wire made of a nickel-titanium-based (Ni—Ti-based) alloy, joined in a solid phase
Data Source
AI summary
A guide wire with improved joining strength is provided. The guide wire includes a first wire and a second wire are solid-phase-joined to each other, the first wire and the second wire are made of a Ni—Ti-based alloy. When a section of a crystal grain size is 1 μm in a number-based particle size distribution of crystal grains of a metallographic structure of a joint surface between the first wire and the second wire, the frequency of the crystal grains having a mode particle size is 25% or more and the frequency of the crystal grains having a crystal grain size with a representative diameter of (mode particle size (μm)−1 μm) or more and (mode particle size (μm)+1 μm) or less is 60% or more.