Laser Welding Spectacle Hinges Without Embrittlement
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Solution Overview
Problem
Conventional methods for attaching hinge parts to spectacle elements, such as electric resistance welding and deep laser welding, face limitations due to material incompatibilities and oxidation issues, leading to brittle welds and potential failure, especially when using materials like zinc or nickel silver.
Innovation Solution
The use of thermal conduction welding with a continuous wave or pulsed laser to create a continuous weld seam along the hinge part, reducing heat input and avoiding vapor capillary formation, allowing for the secure attachment of hinge parts to spectacle elements without embrittlement, even with oxidation-sensitive materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If deep welding with high beam intensity is used to create strong welds, then welding strength is improved, but oxidation-sensitive materials like zinc evaporate and form oxides that embrittle the seam
Solution Approach 1:
The patent applies parameter changes by transitioning from deep welding with high beam intensity to thermal conduction welding with reduced beam intensity. This parameter change prevents the evaporation and oxidation of zinc-containing materials, eliminating embrittlement while maintaining adequate weld strength through controlled thermal processes.
Solution Approach 2:
The patent introduces an inert or protective atmosphere during the welding process to prevent oxidation of evaporation products. This creates a protective environment that prevents harmful chemical reactions between evaporated zinc and oxygen, avoiding oxide formation and seam embrittlement.
2Strength
If electric resistance welding is used to attach hinge parts, then connection strength is improved, but gaps form at welding points preventing liquid-tight or gas-tight sealing
Solution Approach 1:
The patent replaces the mechanical contact-based electric resistance welding with laser-based thermal conduction welding. This substitution enables continuous seam formation without discrete welding points, eliminating gaps and achieving liquid-tight or gas-tight sealing while maintaining connection strength.
Solution Approach 2:
The patent implements continuous useful action by using laser welding to create continuous seams instead of discrete welding points. The continuous laser beam moves along the joint, producing an unbroken weld seam that prevents gap formation and ensures liquid-tight or gas-tight sealing throughout the entire connection.
3Strength
If high contact pressures are applied during welding to ensure strong bonds, then welding strength is improved, but hinge wall thickness must be increased to absorb forces without deformation
Solution Approach 1:
The patent replaces mechanical contact pressure-based welding with laser-based thermal welding. This substitution eliminates the need for high contact pressures and thick hinge walls, as the laser energy directly heats and fuses the materials without requiring mechanical force or bulky structural components to absorb welding forces.
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 method enables a stable, non-brittle weld seam that maintains the functionality of the hinge parts, allowing for a wide range of materials to be used without oxidation issues, resulting in a more reliable and durable connection.
Implementation Method 1
thermal conduction welding. The term 'continuous' refers to the fact that the weld seam is not produced by irradiation of regions that are separated from one another and may overlap in succession, but rather continuously along their longitudinal extent
Implementation Method 2
The laser power or intensity and / or the relative speed between the laser beam and the parts to be welded are preferably varied as a function of the seam length to be produced
Implementation Method 3
If the material of a hinge part or eyeglass element comprises zinc, for example, as is the case with nickel silver, the zinc vapor generated during deep welding can oxidize, so that zinc oxide forms in the area of the weld seam. This leads to an embrittlement of the seam
Data Source
AI summary
The invention relates to spectacles having a middle part and at least one side piece, wherein the at least one side piece is pivotably connected to the middle part by means of a hinge, and wherein the hinge comprises two hinge parts, of which a first is arranged on the at least one side piece and a second is arranged on the middle part. The spectacles are characterised in that at least one of the hinge parts is fastened to the middle part or to the side piece by laser welding, in particular seam welding, and in that a continuous weld seam, which is produced by heat-conduction welding, is formed at least on one longitudinal edge of the hinge part.