Austenitic Suture Needle Pressed Surface Hardness
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Solution Overview
Problem
Suture needles made from austenitic stainless steel with a fiber-elongated structure face limitations in hardness and bending strength at the cutting portion, particularly due to the removal of the hardest portion during grinding and weak bending strength from excessive grinding for sharpness.
Innovation Solution
The suture needle features a cutting portion with one pressed surface and two grinded surfaces, where the cutting edges formed by the intersection of the pressed and grinded surfaces are longer than those formed by the intersection of two grinded surfaces, concentrating hardness at the pressed surface and extending the cutting edge from the sharp tip to the body portion, thereby enhancing hardness and bending strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the cutting portion is heavily ground to sharpen the cutting edge, then the sharpness is improved, but the bending strength deteriorates
Solution Approach 1:
The cutting portion is designed with a pressed surface that has different properties from the grinded surfaces. The pressed surface retains the fiber-elongated structure with higher hardness, while the grinded surfaces provide sharp cutting edges. This local differentiation allows the cutting edge to be sharp without compromising the overall bending strength of the cutting portion.
2Manufacturing precision
If the cutting portion is heavily ground to afford sharpness, then the cutting edge sharpness is improved, but the grinding time increases
Solution Approach 1:
The pressed surface is formed in advance during the manufacturing process, creating a surface with optimal properties for the cutting edge. This preliminary formation reduces the amount of subsequent grinding needed, as the pressed surface already provides a favorable base structure that requires less material removal to achieve the desired sharpness.
3Manufacturing precision
If the cutting portion is heavily ground to sharpen the cutting edge, then the sharpness is improved, but the material loss increases
Solution Approach 1:
By differentiating between the pressed surface and grinded surfaces, the invention minimizes grinding to only the areas necessary for creating sharp cutting edges. The pressed surface is retained where material removal would cause excessive loss, while grinding is applied selectively to create the cutting edges where sharpness is critical.
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
This design achieves higher hardness and bending strength, allowing the suture needle to effectively pierce through hard tissues with reduced piercing resistance and increased durability, while minimizing grinding time and material loss.
Implementation Method 1
an austenitic stainless steel is subject to a cold wiredrawing process with a predetermined reduction of area, whereby a work hardening is generated to enhance hardness
Data Source
AI summary
The goal is to provide a medical suture needle having, as the material, austenite stainless steel with a structure that is elongated in a fiber form while improving the hardness and flexural strength of the cutting portion. A medical suture needle is made of austenite stainless steel having a structure that is elongated in fiber form, and has a cutting portion and a body portion with a triangular cross-sectional shape that is continuous with said cutting portion. The cutting portion has cutting edges, at least one surface of which is formed by a pressed surface, and which are formed by the intersection of said pressed surface with two sharpened surfaces, and a cutting edge that is formed by the intersection of the two sharpened surfaces. The tip where the various cutting edges and converge is positioned in the center of the pressed surface. Moreover, the cutting edges formed by the intersection of the above pressed surface with the two sharpened surfaces are longer than the cutting edge that is formed by the intersection of the two sharpened surfaces.