Hybrid Lap Joint Welding for Inner Corner Metal Deposition
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Solution Overview
Problem
Hybrid welding methods face issues with deposited metal shortage at the inner corner portion when high welding speed is set, leading to decreased joint strength and robustness for clearance and misalignment in lap joints.
Innovation Solution
A joining method using a hybrid welding machine with a preceding laser welding unit and a following MIG welding unit, where the laser beam is emitted onto the front surface of the second metal member, melting a part of it to serve as deposited metal for MIG welding, with specific angles and distances set to enhance the amount of deposited metal at the inner corner portion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If welding speed is increased in hybrid welding, then productivity is improved, but deposited metal shortage occurs at the inner corner portion decreasing joint strength
Solution Approach 1:
The laser welding unit performs preliminary welding before the MIG welding unit, creating a pre-welded structure that prepares the joint for subsequent filler metal deposition. This preliminary action ensures that even at high welding speeds, the inner corner portion receives adequate metal deposition from the laser, preventing throat thickness shortage and maintaining joint strength.
Solution Approach 2:
The patent combines laser welding and MIG welding into a hybrid welding system where the laser welding unit and MIG welding unit work cooperatively. The laser welding unit deposits metal rapidly at high speed, while the MIG welding unit supplements filler metal at the inner corner portion, merging the advantages of both processes to maintain joint strength at high welding speeds.
2Productivity
If welding speed is increased in hybrid welding, then productivity is improved, but robustness for clearance and misalignment decreases
Solution Approach 1:
The patent optimizes welding parameters including the distance between the laser welding unit and MIG welding unit, laser power, and welding speed to create a hybrid welding process that maintains robustness. By carefully controlling these parameters, the system can tolerate clearances and misalignments even at high welding speeds, ensuring reliable weld quality.
3Speed
If laser welding is performed at the corner portion with both laser beam and MIG arc, then welding speed is improved, but the margin for clearance and misalignment becomes significantly small
Solution Approach 1:
The laser welding unit performs preliminary welding at the corner portion before the MIG welding unit arrives, creating a pre-welded structure that is more tolerant of clearances and misalignments. This preliminary laser welding prepares the joint geometry to accommodate variations in positioning while maintaining high welding speed.
Solution Approach 2:
The laser welding acts as an intermediary process between the MIG welding units, creating a preparatory weld structure that mediates the effects of clearance and misalignment. This intermediate laser weld provides a foundation that allows the subsequent MIG welding to compensate for positioning variations while maintaining high speed.
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 method increases welding speed and improves joint strength and robustness for clearance and misalignment by increasing the amount of deposited metal, enhancing the joint's ability to tolerate positional variations.
Implementation Method 1
laser welding is performed by emitting a laser beam onto a front surface of the second metal member
Implementation Method 2
melting a part of it to serve as deposited metal for MIG welding
Implementation Method 3
MIG welding is performed on an inner corner portion formed by the front surface of the first metal member and an end surface of the second metal member
Implementation Method 4
deposited metal (throat thickness) shortage occurs
Data Source
Figure 1
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Figure 4~5
AI summary
A joining method including an overlapping step of overlapping a first metal member and a second metal member such that a front surface of the first metal member is opposed to a back surface of the second metal member; and a welding step of performing a laser welding and a MIG welding by using a hybrid welding machine including a preceding laser welding unit and a following MIG welding unit, in which the laser welding is performed by emitting a laser beam onto a front surface of the second metal member, the MIG welding is performed on an inner corner portion formed by the front surface of the first metal member and an end surface of the second metal member, and a target position for the laser beam from the laser welding unit is located against the second metal member relative to a target position for a MIG arc by the MIG welding unit.