Additively Manufactured Spark Plug Electrode for Durable Tip Bonding
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Solution Overview
Problem
Existing spark plug electrodes face issues with durability and mechanical stability due to uneven weld seams and limited geometrical options, leading to reduced service life and increased production costs, particularly when using precious metals with nickel-based alloys through conventional welding or additive manufacturing methods.
Innovation Solution
A spark plug electrode with an electrode base body made of nickel or a nickel-based alloy and an electrode tip made of a platinum group metal or alloy, manufactured using additive manufacturing with controlled volume energy ranges to create a connection zone of maximum 400 μm thickness, optimizing the composition and microstructure to enhance strength and durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional welding is used to join the electrode tip to the electrode base, then the electrode tip can be attached to the electrode base, but the weld seam creates an uneven joining zone with poor homogeneity and weakens the transition area
Solution Approach 1:
The patent applies additive manufacturing with controlled volume energy ranges (first lower range for connection zone, second higher range for electrode tip) to transform the joining process from conventional welding to selective laser melting. This parameter control enables homogeneous mixing of nickel and platinum group metal in the connection zone while preventing excessive penetration and unevenness, directly resolving the contradiction between connection strength and joining zone homogeneity.
2Manufacturing precision
If conventional additive manufacturing with high volume energy is used to melt the precious metal, then the electrode tip can be formed, but thermal stresses cause cracks in the connection zone reducing durability
Solution Approach 1:
The patent segments the additive manufacturing process into two distinct stages with different volume energy ranges: a first stage with lower volume energy to form the connection zone with minimal thermal stress and crack formation, and a second stage with higher volume energy to form the electrode tip with proper density. This segmentation resolves the contradiction between achieving dense electrode tip structure and preventing cracks in the connection zone.
Solution Approach 2:
The patent applies different volume energy parameters to different spatial zones: lower volume energy is applied specifically to the connection zone area to minimize thermal stress and prevent cracking, while higher volume energy is applied to the electrode tip area to ensure proper melting and density. This local quality approach directly addresses the contradiction between tip density and connection zone durability.
3Adaptability or versatility
If conventional additive manufacturing is used to manufacture the electrode tip, then complex geometries can be achieved, but the manufacturing process is lengthy and production efficiency is reduced
Solution Approach 1:
The patent optimizes the additive manufacturing process by implementing controlled volume energy ranges and a two-stage melting approach, which reduces the overall manufacturing time compared to conventional single-stage processes. The method achieves both complex geometries and improved production efficiency by preventing defects that would require rework and by optimizing the melting parameters for faster, more reliable builds.
4Ease of manufacture
If conventional welding or additive manufacturing is used to join platinum group metal to nickel-based alloy, then the electrode tip can be attached, but the connection zone becomes a weak point reducing service life
Solution Approach 1:
The patent creates a composite connection zone through additive manufacturing where nickel from the electrode base and platinum group metal from the electrode tip are mixed and melted together, forming a homogeneous intermediate structure. This composite approach, achieved through controlled lower volume energy melting, creates a gradient transition zone that is stronger and more durable than conventional weld seams, directly addressing the service life issue while maintaining the feasibility of joining dissimilar metals.
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
The solution results in a more stable and long-lasting spark plug electrode with reduced crack formation and porosity, enabling cost-effective mass production and improved service life compared to conventional methods.
Implementation Method 1
the electrode tip is manufactured layer by layer on the electrode base body by additive manufacturing from a base material containing at least one platinum group metal by melting and solidifying
Implementation Method 2
the first layer of powder is exposed to high volume energy. This is necessary to melt the precious metal and create a dense body in the bonding zone
Implementation Method 3
thermal stresses from the melting and resolidification process cause cracks in the area of the connection zone that forms the transition between the electrode base and the electrode tip
Implementation Method 4
the pores are formed by evaporation of the material, in particular by evaporation of nickel
Data Source
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AI summary
The invention relates to a spark plug electrode (1) comprising an electrode base body (2) and an additively manufactured layer-by-layer electrode tip (3) containing a platinum group metal, wherein the spark plug electrode (1) has a bonding zone (4) formed by melting and solidification, wherein the bonding zone (4) has a thickness (S) of a maximum of 400 µm, and wherein the bonding zone (4), the electrode base body (2), and the electrode tip (3) outside the bonding zone (4) fulfill at least one of the requirements A, B, and C: A) in the bonding zone (4) at least 1 atom% nickel and at least 1 atom% platinum group metal, and outside less nickel or less platinum group metal; B) in the bonding zone (4) a higher total crack length per µm² of cracks than outside the bonding zone; and C) in the bonding zone (4) a larger mean pore diameter than outside the bonding zone.The invention also relates to a method for producing a spark plug electrode (1), a spark plug electrode (1) produced by such a method, a spark plug comprising a spark plug electrode (1) and a method for producing a spark plug.