Needle Holder Jaw Brazing for Precise Insert Alignment
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Solution Overview
Problem
Existing methods for producing surgical needle holders face issues such as microstructure transformations and corrosion due to high brazing temperatures, and relative movements during hardening processes, leading to instability and potential discoloration.
Innovation Solution
A method involving depots in the distal holding jaws for precise braze metering and control, using a nickel braze compatible with arm part hardening, ensuring accurate fitting and alignment of hard metal inserts, and a high-temperature vacuum brazing process to integrate hard metal inserts with stainless steel arm parts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If high-temperature brazing is used to connect hard metal inserts to arm parts, then the connection strength is improved, but microstructure transformations and corrosion resistance deteriorate
Solution Approach 1:
The patent changes the temperature parameter of the brazing process by using a low-temperature brazing alloy (melting point 900-1100°C) instead of conventional high-temperature brazing. This parameter change allows achieving adequate connection strength while avoiding microstructure transformations and corrosion issues in the martensitic arm parts that occur at higher temperatures.
2Strength
If high-temperature vacuum brazing is used during hardening process, then the hard metal inserts are connected to arm parts, but relative movements occur due to different coefficients of thermal expansion
Solution Approach 1:
The patent changes the temperature parameter by using low-temperature brazing (900-1100°C) instead of high-temperature brazing during hardening. This reduces the thermal expansion differences between stainless steel arm parts and hard metal inserts, preventing relative movements and maintaining alignment precision while still achieving strong connections.
3Strength
If silver braze is used for brazing process, then the hard metal inserts are connected to arm parts, but black discoloration occurs over time
Solution Approach 1:
The patent changes the material composition parameter by using a nickel-based or copper-based brazing alloy instead of silver braze. This material substitution eliminates the black discoloration issue that occurs with silver braze over time, while maintaining adequate connection strength through the low-temperature brazing process.
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 method enhances stability, reduces corrosion, minimizes manual work, and lowers production costs while ensuring precise fitting and alignment, resulting in improved surgical instruments for grasping and guiding needles.
Implementation Method 1
brazing the hard metal insert inserted into the recess in the distal holding jaw of the first arm part to the first arm part and brazing the hard metal insert inserted into the recess in the distal holding jaw of the second arm part to the second arm part, with the aid of the braze in each case
Implementation Method 2
a high-temperature vacuum brazing process to integrate hard metal inserts with stainless steel arm parts
Data Source
AI summary
A method for producing a surgical instrument for grasping and/or holding and/or guiding a needle includes: a) producing a first arm part and a second arm part, each having a distal holding jaw with a recess and a solder deposit region; b) inserting hard metal inserts into the recesses in the distal holding jaws; c) joining the first arm part and the second arm part so that the first arm part and the second arm part are pivotable relative to one another at a joint; d) filling the solder deposit regions with solder; and e) soldering the hard metal inserts in the distal holding jaws using the solder.