Additive-Manufactured Spark Plug Electrode Tips Without Weld Cracking
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Solution Overview
Problem
Spark plug electrodes face challenges such as erosion and corrosion due to harsh engine environments, and traditional joining methods like laser welding can introduce thermal stresses and precision issues with precious metal electrode tips, affecting performance and cost-effectiveness.
Innovation Solution
The use of additive manufacturing processes, specifically powder bed fusion techniques, to form precious metal-based electrode tips that overhang the electrode base, providing a weldless joint and improved precision and durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If laser welding is used to attach precious metal electrode tips to electrode bodies, then the electrode tip can be securely attached, but thermal stresses and cracking can occur due to different material properties
Solution Approach 1:
The patent merges the electrode tip and electrode body into a single integrated component formed by additive manufacturing, eliminating the weld joint that causes thermal stress and cracking. The process directly deposits precious metal material onto the electrode base to form the tip, creating a unified structure without requiring separate attachment steps.
Solution Approach 2:
The patent changes the manufacturing parameters from conventional joining (laser welding with high heat input) to additive manufacturing (controlled material deposition). This parameter change allows for precise control of the material structure and eliminates the thermal cycle that causes stress and cracking in welded joints.
2Reliability
If precious metals are used throughout the entire electrode body, then erosion and corrosion resistance is improved, but the cost increases significantly
Solution Approach 1:
The patent applies local quality by using precious metal material only where it is most needed - at the electrode tip where the spark occurs and erosion/corrosion is most severe. The electrode base uses a less expensive nickel alloy, creating a cost-effective gradient structure that provides maximum protection at the critical location while minimizing overall material cost.
Solution Approach 2:
The patent segments the electrode into two functional zones: a precious metal tip for spark generation and erosion resistance, and a nickel alloy base for structural support and heat dissipation. This segmentation allows each material to be used where it provides the most value, optimizing both performance and cost.
3Ease of manufacture
If traditional joining methods are used to attach electrode tips, then the manufacturing process is simple, but achieving precise parallelism and tight spark gap tolerances is difficult
Solution Approach 1:
The patent combines the electrode tip formation and positioning into a single additive manufacturing process step, eliminating separate alignment and attachment operations. The tip is directly built onto the base in its final position, ensuring precise parallelism and tight tolerances without requiring complex fixture setups or multi-step assembly procedures.
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 enhances the voltage requirements, flame growth, and spark gap tolerances while reducing the erosion rate of precious metals and lowering costs by optimizing the use of expensive materials.
Implementation Method 1
an electrode tip that is formed on the electrode base and includes a precious metal-based material and a plurality of laser deposition layers
Implementation Method 2
the electrode tip overhangs at least a portion of the edge
Data Source
AI summary
A spark plug electrode with one or more electrode tip(s) formed on one or more electrode base(s) using an additive manufacturing process, such as a powder bed fusion technique, such that each electrode tip overhangs an edge of a corresponding electrode base. The spark plug electrode may be a center electrode, a ground electrode, or an annular ground electrode and can be provided according to a number of different configurations. Each electrode tip includes a precious metal-based material, such as an iridium- or platinum-based alloy, and a plurality of laser deposition layers, and each electrode tip can be secured to an electrode base with a weldless joint. An additive manufacturing process is also provided.