Rail Vehicle Skin Laser Welding Distortion Control
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Solution Overview
Problem
The existing methods for producing outer skins of large rail vehicle components in differential construction often result in distortion due to welding, requiring costly post-processing steps like straightening and grinding to achieve a flat surface, and increasing weight by using thicker metal or are difficult to automate with riveting.
Innovation Solution
A method involving the separation of metal sheets, insertion of thicker sheet metal strips, and laser welding to create a grid of reinforcements, allowing for localized thickness increases at connection points, reducing distortion and enabling automation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If welding is used to join the outer skin to the reinforcing structure, then the components can be connected, but distortion occurs requiring costly post-processing
Solution Approach 1:
The patent applies local quality by varying the sheet metal thickness at different locations. The outer skin has increased thickness (e.g., 2-3mm) at connection points to the reinforcing structure while maintaining standard thickness elsewhere. This localized thickness increase provides sufficient structural strength and distortion resistance at weld points without increasing the overall weight of the vehicle body.
Solution Approach 2:
The outer skin is segmented into regions of different thicknesses through controlled rolling or layering processes. This segmentation allows the thin-gauge sheet metal to have thickened zones specifically at connection points, enabling welding without distortion while keeping the majority of the skin lightweight.
2Manufacturing precision
If thicker sheet metal is used to prevent distortion, then welding distortion is reduced, but the vehicle weight increases
Solution Approach 1:
The patent applies local quality by varying the sheet metal thickness at different locations. The outer skin has increased thickness (e.g., 2-3mm) at connection points to the reinforcing structure while maintaining standard thickness elsewhere. This localized thickness increase provides sufficient structural strength and distortion resistance at weld points without increasing the overall weight of the vehicle body.
3Manufacturing precision
If riveting is used instead of welding to avoid distortion, then outer skin flatness is maintained, but automation becomes difficult
Solution Approach 1:
The patent changes the physical parameters of the outer skin by varying its thickness. By creating thickened zones at connection points through controlled rolling or layering, the material properties are altered locally to enable welding without distortion, thus allowing automation while maintaining flatness.
4Manufacturing precision
If complex post-processing steps are applied to correct distortion, then outer skin flatness is achieved, but manufacturing cost and time increase
Solution Approach 1:
The patent applies preliminary action by pre-thickening the outer skin at connection points before the welding process. This preventive measure ensures that the material has sufficient strength and rigidity to resist welding-induced distortion, thereby eliminating the need for subsequent corrective operations like straightening, cementing, or grinding.
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 produces a distortion-free outer skin with increased rigidity and reduced warping, eliminating the need for post-processing and allowing for lighter rail vehicle components while enabling efficient automation.
Implementation Method 1
welding the edges of the divided metal sheets and the metal strip to form a complete metal sheet
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
Method for manufacturing a skin (1) for a large component of a rail vehicle using differential construction, wherein a metal panel (3) is divided and a sheet metal strip (5) is welded into the separation gap.