Copper Laser Welding for Low-Thermal Motor Coil Joints
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional welding methods, such as arc welding, face challenges when dealing with copper-based conductor segments in electric rotating machines due to high heat input, which can damage insulating coatings and make it difficult to reduce coil end portion size, while laser welding struggles with copper's low energy absorption rate at typical wavelengths.
Innovation Solution
A laser welding method utilizing a combination of two laser lights, where the first laser (with a wavelength of 470 nm or less) heats the material, increasing its temperature to enhance copper's energy absorption rate, allowing the second laser (with a wavelength of 800 nm or more) to apply high energy density for efficient welding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If arc welding is used to weld conductor segments, then welding strength is achieved, but thermal influence melts the insulating coating and increases coil end portion size
Solution Approach 1:
The welding process is segmented into two distinct stages: preheating (first laser light) and welding (second laser light). This segmentation allows thermal management by separating the heating phase from the high-energy welding phase, preventing excessive thermal influence on the insulating coating while maintaining welding strength.
Solution Approach 2:
The first laser light performs preliminary action by preheating the copper-based material before the actual welding process. This preliminary heating increases the material's temperature to a state where it can efficiently absorb the second laser light's energy, enabling welding with reduced overall thermal influence on surrounding areas.
2Power
If laser light is used for welding copper, then high energy density is achieved, but copper's low energy absorption rate prevents effective welding
Solution Approach 1:
The invention changes the temperature parameter of the copper-based material through preheating with the first laser light. This parameter change transforms copper from a state of low energy absorption rate to a state of high energy absorption rate, enabling effective welding with the second laser light while maintaining high energy density.
Solution Approach 2:
The first laser light acts as an intermediary that mediates between the second laser light and the copper-based material. It prepares the material by increasing its temperature and energy absorption rate, enabling the second laser light to effectively transfer energy to the copper for welding.
3Ease of manufacture
If arc welding is used, then welding can be performed, but grounding is required and coil end portion size cannot be reduced
Solution Approach 1:
The invention replaces the arc welding process (which requires grounding and creates high thermal influence) with a two-stage laser welding process. This substitution eliminates the need for grounding while reducing thermal influence, allowing for simpler device setup and reduced coil end portion size.
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 precise welding of copper-based conductor segments with reduced thermal influence, allowing for smaller coil end portions and increased production capacity without additional equipment, while maintaining high welding strength and reducing variation in the welding process.
Implementation Method 1
heating the material (10) by irradiation with a first laser light (L1)
Implementation Method 2
heating the material (10) by irradiation with a first laser light (L1)
Implementation Method 3
the energy absorption rate of copper contained in the material (10) increases by an increase in a temperature of the material (10)
Implementation Method 4
welding the material (10) by irradiation of a portion, which has been irradiated with the first laser light (L1), of the material (10) with a second laser light (L2)
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
In a laser welding method, a material (10) containing copper as a main component is heated by irradiation with a first laser light (L 1), and is welded by irradiation of a portion, which has been irradiated with the first laser light (L1), of the material (10) with a second laser light (L2) with which the energy absorption rate of copper contained in the material (10) increases by an increase in the temperature of the material (10).