Laser Overlay Welding Energy Control at Weld Bead Overlaps
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Solution Overview
Problem
Laser overlay welding methods face challenges in suppressing fusion failure at the overlap portions of weld beads while minimizing thermal effects on metal members.
Innovation Solution
The method involves adjusting the energy density of the laser beam to be higher at the overlapping portions of adjacent weld beads during the overlay welding process, using a welding device that supplies weld metal powder and irradiates the metal member with a laser beam, and includes a tab disposition step to prevent powder fallout and increase bead thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the energy density of the laser beam is increased at overlapping portions of weld beads, then fusion failure is suppressed, but thermal effect on the metal member increases
Solution Approach 1:
The patent applies local quality by adjusting the energy density distribution of the laser beam specifically at the overlapping portions of weld beads. The control unit increases energy density only in the overlap regions where fusion failure is likely to occur, while maintaining lower energy density in non-overlapping regions. This localized energy adjustment suppresses fusion failure at critical areas without unnecessarily increasing thermal effects across the entire workpiece.
Solution Approach 2:
The patent implements dynamics by dynamically adjusting the energy density of the laser beam based on real-time identification of weld bead overlap regions. The control unit modifies the laser beam parameters (such as power distribution or focal position) in response to the detected overlap conditions, enabling adaptive control that optimizes fusion prevention while minimizing overall thermal input to the metal member.
2Ease of manufacture
If the energy density is uniformly distributed, then the welding process is simple, but fusion failure occurs at overlap portions
Solution Approach 1:
The patent employs feedback by using an imaging device to detect the positions and dimensions of previously formed weld beads, then using this information to control the energy density distribution for subsequent weld beads. The control unit receives feedback about overlap regions from the imaging device and automatically adjusts the laser beam energy density accordingly, ensuring reliable fusion prevention without manual intervention or complex procedural changes.
Solution Approach 2:
The patent applies parameter changes by modifying the energy density parameter of the laser beam based on the spatial location relative to weld bead overlaps. Instead of using a uniform energy density, the system varies the energy density parameter dynamically - increasing it in overlap regions and maintaining it at standard levels in non-overlap regions, thereby preventing fusion failure while keeping the overall process straightforward.
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 approach effectively suppresses fusion failure and thermal effects by optimizing heat input at overlap areas without increasing the overall energy density, ensuring accurate energy distribution and improved weld bead formation.
Implementation Method 1
irradiating a surface of a metal member with a laser beam while supplying a weld metal powder, and performing overlay welding on the surface of the metal member, in which a weld bead formation step of melting and solidifying the weld metal powder with the laser beam to form a weld bead
Data Source
AI summary
An overlay welding method includes irradiating a surface of a metal member with a laser beam while supplying a weld metal powder, and performing overlay welding on the surface of the metal member, and repeatedly performing a weld bead formation step of melting and solidifying the weld metal powder with the laser beam to form a plurality of weld beads on the surface of the metal member. Each of the plurality of weld beads has one portion in a width direction overlapping each other. In the overlay welding method, in a case of forming an adjacent weld bead, which is a weld bead adjacent to a previously formed weld bead, an energy density of the laser beam is adjusted to be higher at a portion of the adjacent weld bead overlapping the previously formed weld bead than at a portion not overlapping the previously formed weld bead.