Endodontic Instrument Blanks with Wire-Eroded Cutting Edge Patterns
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Solution Overview
Problem
Conventional methods for producing endodontic instruments are time-consuming, cost-intensive, and limited in surface configurations, with existing methods either being mechanically disadvantageous due to material redeposition or requiring high-temperature processes that corrode the material.
Innovation Solution
The method involves applying an erosion pattern to a rod during wire erosion, removing the eroded material to prevent redeposition, and using a combination of techniques like EDM and ultrasonic machining, with adjustable current and pulse times, and powder additives to enhance material properties, allowing for superelastic properties and efficient cutting edge configurations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional twisting or grinding methods are used to produce endodontic instruments, then cutting edges and grooves can be formed, but the production process is time-consuming and cost-intensive
Solution Approach 1:
The patent replaces conventional mechanical twisting and grinding methods with electrical discharge machining (EDM) and wire erosion processes. These electrical-based methods form cutting edges and grooves through controlled material removal via electrical discharges, significantly reducing production time while maintaining precision surface configurations that match clinical requirements
Solution Approach 2:
The patent utilizes phase transitions of nickel-titanium alloy (austenite to martensite transformation) during the manufacturing process. By controlling temperature and stress parameters, the material transforms phases to enable precise shaping through EDM and wire erosion, then returns to austenite phase for final superelastic properties, achieving both high productivity and manufacturing precision
2Productivity
If electrical discharge machining is used to form grooves and cutting edges, then production time is reduced, but eroded material deposits on the instrument creating a harder layer that is mechanically disadvantageous
Solution Approach 1:
The patent applies a removal step specifically targeting the re-deposited material layer formed during EDM processing. This extraction process eliminates the mechanically disadvantageous hardened deposit while preserving the precisely formed cutting edges and grooves, thereby maintaining high productivity without compromising mechanical performance
Solution Approach 2:
The patent acknowledges that material re-deposition during EDM creates a harder layer, but instead of viewing this purely as a defect, the process controls and subsequently removes this layer to prevent mechanical disadvantages. The controlled re-deposition followed by selective removal ensures clean surfaces with optimal mechanical properties while maintaining the efficiency gains from EDM
3Strength
If high-temperature processing is used to produce superelastic instruments, then superelastic properties are achieved, but the material undergoes corrosive effects
Solution Approach 1:
The patent carefully controls temperature parameters during processing to achieve the necessary austenite-to-martensite phase transformation for superelastic properties, then rapidly cools and stabilizes the material to prevent excessive thermal exposure that would cause corrosion. This parameter optimization achieves the required strength without harmful corrosive effects
Solution Approach 2:
The patent employs intermediate protective measures during high-temperature processing, such as controlled atmospheric environments or protective coatings, that act as intermediaries between the heat treatment process and the nickel-titanium alloy material, enabling the necessary phase transformations while preventing corrosive damage to the material surface
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 approach enables rapid, cost-effective production of endodontic instrument blanks with improved stability and functionality, reducing mechanical stress and maintaining homogeneous properties through nanoindentation-hardened cutting edges.
Implementation Method 1
The method involves applying an erosion pattern to a rod during wire erosion
Implementation Method 2
a combination of ultrasonic machining and EDM machining
Data Source
Figure 1
Figure 2A~2B
AI summary
The invention relates to a blank for an endodontic instrument, obtainable by machining at least one rod by means of wire erosion, preferably selected from the group consisting of electrical discharge machining, wire electrical discharge machining, electrical discharge grinding and electro-chemical machining, wherein an erosion pattern is applied to the at least one rod, wherein the blank has a homogenous hardness.