Spark Plug Electrode Welding Seam Mixing Control
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Solution Overview
Problem
Spark plug electrodes face limited service life due to corrosion and erosion, and the integration of noble metal and nickel alloy components with different thermal expansion coefficients leads to mechanical stresses and potential cracking in the welding seam, reducing the longevity and reliability of spark plugs.
Innovation Solution
A spark plug electrode design with a welding seam where the mixing rate of materials is less than 15 weight percent, achieved through line scans to ensure uniform distribution of elements, and a manufacturing method using a laser scanner welding process with a tilted reflection element to enhance material mixing and reduce thermal stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If noble metal and nickel alloy components are welded together to join different materials, then the service life and corrosion resistance of the spark plug electrode is improved, but mechanical stresses occur in the welding seam due to different thermal expansion coefficients
Solution Approach 1:
The patent applies parameter changes by controlling the mixing rate of materials in the welding seam to be less than 15 weight percent. This parameter control creates a gradient structure that accommodates thermal expansion differences between noble metal and nickel alloy, reducing mechanical stress while maintaining the reliability benefits of material joining.
Solution Approach 2:
The patent creates a composite welding seam structure where noble metal and nickel alloy materials are combined with controlled mixing. This composite approach allows the welding seam to exhibit properties intermediate between the two base materials, reducing thermal expansion mismatch stresses while maintaining both corrosion resistance and structural integrity.
2Strength
If high mixing rate of materials occurs in the welding seam, then material bonding is achieved, but crack formation increases and welding seam stability decreases
Solution Approach 1:
The patent fundamentally resolves this contradiction by inverting the conventional approach: instead of maximizing mixing for bonding, it limits mixing to less than 15 weight percent. This parameter change creates a controlled gradient structure that maintains adequate bonding while preventing the crack formation associated with high mixing rates, thereby improving welding seam stability.
Solution Approach 2:
The patent applies local quality by creating different material mixing characteristics at different locations within the welding seam. The mixing rate is controlled to be less than 15 weight percent in the half adjacent to the ignition element, while allowing different mixing characteristics elsewhere. This localized control optimizes both bonding strength and crack resistance in different regions of the welding seam.
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 approach results in a more stable and longer-lasting welding seam, reducing mechanical stress and crack formation, thereby extending the service life of the spark plug electrode and improving its durability.
Implementation Method 1
Laser welding is very widespread in the joining of Ir-based ignition elements to Ni-based base bodies
Implementation Method 2
a welding beam (5), in particular a laser beam, is radiated onto the joining point
Implementation Method 3
via a reflection element (6), for example a mirror, the welding beam (5) is directed onto the joining point
Data Source
AI summary
A spark plug electrode includes an electrode base body made of a first material and an ignition element made of a second material and forming an ignition surface for a spark plug. The electrode base body and the ignition element are integrally joined to each other via a welding seam. A mixing rate for the first or second materials is less than 15 weight percent in a half of the welding seam adjacent to the ignition element. A method for manufacturing a spark plug electrode includes: providing an electrode base body and an ignition element; carrying out a welding process joining the electrode base body and the ignition element while forming a welding seam, where a welding beam guided over the surface of the spark plug electrode by tilting a reflection element, thereby producing a welding seam at a joining point between the electrode base body and the ignition element.