Non-overlapping Laser Welding for High-speed Joint Strength
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Solution Overview
Problem
Conventional laser welding methods face limitations in increasing scan speed due to insufficient energy for melting, leading to potential laser pass-through and inadequate joint strength, as well as metal evaporation issues when using high-energy beams.
Innovation Solution
A manufacturing method employing non-overlapping irradiation with a primary laser beam and subsequent high-energy beams, where the advanced beam is emitted ahead and the subsequent beam is emitted behind the primary beam, ensuring the boundary is melted without overlap, thus preventing pass-through and metal evaporation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the scan speed of the laser beam is increased, then productivity is improved, but the temperature of the area ahead of the irradiation position cannot be sufficiently increased, resulting in insufficient joint strength
Solution Approach 1:
The patent applies preliminary action by emitting the advanced laser beam ahead of the primary laser beam to preheat the area in front of the irradiation position. This preheating action prepares the material in advance, allowing the primary laser beam to effectively melt and join the members even at high scan speeds, thereby resolving the contradiction between productivity and joint strength.
2Temperature
If the energy of the low-density laser beam is increased, then the temperature ahead of the high-density laser beam can be increased, but laser pass-through occurs where the beam passes through the boundary between joint targets
Solution Approach 1:
The advanced laser beam performs preliminary heating of the area ahead of the primary laser beam without reaching the boundary between joint targets. This allows sufficient temperature increase to enable high scan speeds while the primary laser beam's high energy density ensures complete melting and prevents pass-through, resolving the contradiction between temperature increase and reliability.
Solution Approach 2:
The patent applies local quality by using different laser beams with different energy densities for different purposes: the advanced laser beam provides distributed preheating over a wider area, while the primary laser beam concentrates high energy density at the boundary to ensure complete melting and prevent pass-through. This localized differentiation resolves the contradiction between temperature increase and preventing laser pass-through.
3Strength
If high-energy laser beams are used to melt the irradiation target, then joint strength is improved, but metal evaporation occurs causing welding failure
Solution Approach 1:
The advanced laser beam performs preliminary heating to raise the temperature of the material ahead of the primary laser beam. This reduces the energy density requirement for the primary laser beam, allowing it to melt the material effectively without exceeding the threshold that causes metal evaporation, thus resolving the contradiction between joint strength and preventing welding failure.
Solution Approach 2:
The patent uses a sequence of laser beams (advanced laser beam followed by primary laser beam) in a periodic manner. The advanced laser beam heats the material first, then the primary laser beam completes the melting process. This periodic action allows energy to be delivered in controlled stages, preventing excessive energy concentration that would cause metal evaporation while still achieving strong joints.
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
Enables high-speed laser welding with enhanced joint strength and reduced failure risk by maintaining high energy levels without causing metal evaporation, ensuring a robust and efficient welding process.
Implementation Method 1
an advanced laser beam whose irradiation position is in front of a primary laser beam in a direction of movement... the temperature of an area ahead of an irradiation position of the high-density laser beam can be increased
Implementation Method 2
the primary laser beam is emitted along a primary trajectory on the boundary between the first member and the second member... the boundary between the case body and the sealing plate is joined by the laser welding
Implementation Method 3
a subsequent laser beam whose irradiation position is at rear of the primary laser beam in the direction of movement... the subsequent laser beam is emitted along a subsequent trajectory
Data Source
AI summary
A manufacturing method includes i) emitting a primary laser beam along a primary trajectory on a boundary between a first member and a second member by a welding apparatus; ii) emitting an advanced laser beam along an advanced trajectory that does not overlap the primary trajectory by the welding apparatus; and iii) emitting a subsequent laser beam along a subsequent trajectory that does not overlap the primary trajectory and the advanced trajectory by the welding apparatus.