Medical Cutting Tool Brazing with Copper Interlayer
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The bonding of stainless steel or carbon steel shank portions with cemented carbide working portions using friction pressure welding, resistance welding, or brazing leads to thermal effects that reduce the strength of the shank and cause oxidation, resulting in potential rust and fractures, especially when martensitic stainless steel or carbon steel is used, which lacks improved strength and is prone to rust.
Innovation Solution
A medical cutting tool is formed by brazing a cemented carbide or ceramic working portion to a round austenitic stainless steel shank portion, with a fiber-shaped structure in the joint and neck area, maintaining a granular structure at the joint to prevent fractures and ensure flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If friction pressure welding, resistance welding, or brazing is used to bond the shank portion and working portion, then the bonding strength is improved, but thermal effects cause oxidation of cemented carbide and reduction of shank strength
Solution Approach 1:
A copper intermediate layer is introduced between the cemented carbide working portion and the stainless steel shank portion. This copper layer acts as a thermal barrier and protective intermediary during the bonding process, preventing direct thermal damage and oxidation to the cemented carbide while facilitating the bonding process. The copper layer is subsequently removed after bonding is complete.
Solution Approach 2:
The bonding process is performed in a vacuum environment, which creates an inert atmosphere that prevents oxidation of the cemented carbide working portion. By removing oxygen from the environment during heating and bonding, the harmful oxidative effects are eliminated while still allowing thermal bonding to occur.
2Strength
If martensitic stainless steel or carbon steel is used for the shank portion, then the strength can be improved through heat treatment, but rust generation and fracture risk increase
Solution Approach 1:
The material composition parameters of the shank portion are changed from martensitic stainless steel or carbon steel to austenitic stainless steel. This material substitution fundamentally changes the properties: austenitic stainless steel provides adequate strength without requiring heat treatment, maintains excellent rust resistance, and reduces fracture risk while still enabling successful bonding to the cemented carbide working portion.
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 tool effectively resists bending and warping during cutting operations, maintaining high strength and preventing rust, with the fiber-shaped structure in the shank portion providing durability and flexibility, while the granular structure at the joint enhances joint flexibility and reduces fracture risk.
Implementation Method 1
a copper layer which prevents oxidation of the working portion 2 during heating is formed on a surface of the working portion 2
Implementation Method 2
in a vacuum, a copper layer which prevents oxidation of the working portion during heating
Implementation Method 3
formed by brazing a working portion formed of cemented carbide or ceramic to a leading end of a shank portion
Data Source
AI summary
Method of producing a medical cutting tool and a medical cutting tool that will not rust and that is capable of stably demonstrating high strength. A working section formed by a cemented carbide or ceramic is brazed to the tip of a shank part formed by a round bar-shaped austenitic stainless steel, thereby constituting a cutting tool. The shank part includes a shank, a neck, and a joint to which the working section is brazed. At least part of the stainless steel near the joint of the neck and in the joint has a fiber-like structure. The structure of the stainless steel in the joint on the working section side has a granular structure.