Iridium Spark Plug Electrode Bending Angle Optimization
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Solution Overview
Problem
The production of ignition electrodes for prechamber spark plugs from iridium or iridium-based alloys is challenging due to their brittle nature, leading to breakage or cracking during the bending process, which affects the service life and increases production costs.
Innovation Solution
Cutting the ignition electrode blank from sheet metal with an angle of 50° or less between each arm and the rolling direction, allowing for sufficient flexibility without additional manufacturing effort, and using iridium-based alloys with high iridium content and alloying additives like osmium and hafnium for improved properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If iridium or iridium-based alloys are used for the ignition electrode, then the melting point and wear resistance are improved, but the material becomes very brittle and prone to breakage during bending
Solution Approach 1:
The patent changes the geometric parameters of the electrode blank by specifying precise cutting angles (45° or 60° relative to rolling direction) and thickness ratios (thickness to width between 1:10 and 1:20). These parameter changes optimize the material's flexibility-to-strength ratio, allowing the brittle iridium alloy to be bent without breakage while maintaining its high melting point and wear resistance properties.
2Ease of manufacture
If the electrode arms are bent from a cross-shaped blank, then the ignition electrode structure is formed, but the brittle iridium material breaks or cracks during bending
Solution Approach 1:
The patent specifies critical geometric parameters for the blank: cutting angles of 45° or 60° relative to the rolling direction, and thickness-to-width ratios between 1:10 and 1:20. These parameter changes create optimal stress distribution during bending, enabling the formation of electrode arms from brittle iridium material without breakage or cracking.
Solution Approach 2:
The patent performs preliminary preparation by precisely controlling the blank's geometry before bending. The specific cutting angles and thickness specifications are established in advance to pre-condition the material for successful bending, preventing breakage before it occurs during the forming process.
3Productivity
If conventional bending processes are used for iridium alloys, then production costs increase due to breakage and cracking, but the service life is reduced
Solution Approach 1:
The patent optimizes geometric parameters (cutting angles of 45° or 60°, thickness-to-width ratios of 1:10 to 1:20) to enable successful bending of iridium blanks. This eliminates production breakage and cracking, simultaneously improving production efficiency by reducing waste and service life by ensuring complete, crack-free electrodes for long-term operation.
Data Source
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AI summary
The invention relates to a method for manufacturing an ignition electrode (7) for a pre-chamber spark plug, wherein an ignition electrode blank is cut from a sheet metal blank and the electrode arms (7) are then formed by bending. According to the invention, the sheet metal is produced from iridium or an iridium-based alloy by rolling in one direction, and the ignition electrode blank is cut such that there is an angle of 50° or less between each of the electrode arms (7) and the rolling direction (W). The invention further relates to a corresponding pre-chamber spark plug.