Door Sash Welding Segmentation for Distortion Control
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Solution Overview
Problem
Existing door sash manufacturing methods using roll forming and welding suffer from distortion and deformation during bending, as stress concentration varies with position, leading to uneven shapes and potential rusting due to gaps in welding.
Innovation Solution
A door sash design featuring elongated metal plates with two welding marks and a continuous fusion portion formed by seam welding, which mitigates stress concentration and maintains continuous welding without gaps, reducing distortion and deformation while enhancing torsional rigidity and preventing rusting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If seam welding is performed only at the central fusion portion during roll forming, then welding speed and productivity are improved, but distortion and deformation occur during subsequent bending due to uneven stress distribution
Solution Approach 1:
The welding process is segmented into two distinct stages: first, rapid seam welding at the central fusion portion during roll forming to ensure productivity; second, supplementary spot welding at both end portions of the joint after bending to eliminate stress concentration and prevent distortion. This segmentation allows each welding method to optimize for its specific function.
Solution Approach 2:
The central fusion portion is welded in advance during the roll forming process before bending occurs. This preliminary welding establishes the basic structural integrity and allows the subsequent bending and spot welding steps to address only the remaining stress concentration issues at the ends.
2Weight of moving object
If the metal plate thickness is reduced to decrease weight, then weight reduction is achieved, but torsional rigidity and resistance to deformation during bending are insufficient
Solution Approach 1:
The joint structure functions as a composite system combining three metal plate layers with dual welding methods (seam welding at center + spot welding at ends). This composite construction creates a synergistic effect where the multi-layer structure and distributed welding provide enhanced torsional rigidity and bending resistance that cannot be achieved by simply increasing the thickness of a single plate.
3Device complexity
If welding is performed only at the central fusion portion, then manufacturing complexity is reduced, but gaps at the end portions allow water penetration and rusting
Solution Approach 1:
The protective welding coverage is segmented by applying seam welding to the central fusion portion during forming and spot welding to the end portions after bending. This segmented approach ensures complete gap closure at all critical locations while maintaining manufacturing efficiency through the use of different welding methods for different zones.
Solution Approach 2:
Different welding methods are applied to different locations based on local requirements: seam welding at the central fusion portion provides continuous coverage for the main body, while spot welding at the end portions provides targeted protection against water penetration at these critical stress and exposure points.
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 solution significantly reduces distortion and deformation, maintains a good design appearance, decreases weight by allowing thinner metal plates, and prevents rusting by ensuring continuous welding without gaps.
Implementation Method 1
uniting the superimposed portions together by welding
Implementation Method 2
the portions superimposed through roll forming are welded together along a line by seam welding or laser welding
Implementation Method 3
formed by superimposing flat portions of an elongated metal plate by roll forming
Implementation Method 4
bending the metal plate in a longitudinal direction
Data Source
AI summary
When a formed product having undergone roll forming and welding is bent in the shape of a door sash, the formed product may distort and/or deform. Such distortion and/or deformation is reduced to a sufficient degree. A door sash is formed by bending an elongated metal plate in a widthwise direction such that portions thereof are superimposed, which are welded together for unification. The door sash has a joint portion extending in a longitudinal direction and having exposed surfaces extending continuously in the widthwise direction, a pocket portion extending continuously from one widthwise end of the joint portion and being to be located on the inner side of a vehicle, and a design portion extending continuously from the other widthwise end of the joint portion and being to be located on the outer side of the vehicle. The door sash is bent in the longitudinal direction, and has two parallel welding marks formed on each of the exposed surfaces of the joint portion and extending in the longitudinal direction.