Serpentine Welding for Honeycomb Core Flatness
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Solution Overview
Problem
The existing methods for creating honeycomb cores, particularly those made of metal sheets, face issues with curvature due to shrinkage during welding, leading to uneven surfaces and increased production time and expense, and the process of creating angled cores results in significant material waste.
Innovation Solution
A method utilizing a serpentine welding pattern with alternating long and short welds to minimize curvature and allow for the expansion of metal sheets into honeycomb cores, while also enabling the creation of angled cores without material wastage by strategically trimming and shifting welding patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If parallel linear weld paths are used to bond metal sheets, then the sheets are securely joined, but curvature and uneven surfaces develop due to shrinkage
Solution Approach 1:
The weld path is segmented into multiple sections (first weld section, second weld section, third weld section) rather than using continuous parallel linear welds. This segmentation allows for controlled shrinkage distribution and reduces cumulative curvature effects across the sheet stack.
Solution Approach 2:
The invention uses serpentine or curved weld paths instead of straight linear welds. The curved geometry distributes thermal stress and shrinkage more evenly, preventing the development of excessive curvature and maintaining surface flatness while still achieving secure bonding.
2Quantity of substance
If the stack size is increased to create larger cores, then more sheets can be bonded, but curvature increases making the surface uneven
Solution Approach 1:
The welding process is divided into multiple passes with different weld path configurations. By alternating between different serpentine patterns in successive welding passes, the cumulative shrinkage effects are balanced and distributed, allowing larger stacks to be welded without excessive curvature development.
Solution Approach 2:
The welding process uses periodic alternation between different serpentine weld patterns (first pattern, second pattern, third pattern) in successive passes. This periodic variation in weld path geometry compensates for accumulated curvature and maintains surface flatness even as the number of sheets in the stack increases.
3Shape
If flattening techniques are applied to correct curvature, then surface flatness is restored, but production time and expense increase
Solution Approach 1:
The serpentine weld path configuration is designed beforehand to preemptively compensate for expected shrinkage and curvature development. By planning the weld paths to account for thermal contraction in advance, the need for subsequent flattening operations is eliminated, reducing both time and cost.
Solution Approach 2:
The invention converts the harmful effect of weld-induced shrinkage into a beneficial outcome by using serpentine path geometry. The curved paths are specifically designed to utilize the shrinkage effect to maintain flatness rather than fight against it, eliminating the need for corrective flattening operations.
4Shape
If sides are cut at wedge-shaped angles to create angled cores, then the desired angle is achieved, but a large amount of core material is wasted
Solution Approach 1:
The serpentine weld paths are configured in advance to account for the desired angled configuration. By planning the weld geometry to pre-compensate for the angle requirement, material waste from traditional cutting methods is eliminated while still achieving the desired core angle.
Solution Approach 2:
The invention changes the welding parameters (path geometry, sequence, and configuration) to directly produce the angled core configuration without requiring subsequent material removal. This parameter change in the welding process itself eliminates the need for wasteful cutting operations.
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 reduces curvature-related issues and material waste, enhancing the efficiency and cost-effectiveness of honeycomb core production while maintaining structural integrity and allowing for customizable dimensions and angles.
Implementation Method 1
welding the first sheet to the second sheet using a first serpentine welding pattern
Implementation Method 2
Each weld path may cause a slight shrinkage in the foil along the weld path, which in turn may cause the foil to curl on the sides of the weld path
Data Source
AI summary
A honeycomb core is created from a stack of metal sheets that are welded together using a serpentine weld path. Each sheet in the stack is welded to the sheet underneath. All the odd-numbered sheets, excluding the bottom sheet, are welded using a first serpentine welding pattern that includes a plurality of long welds and a plurality of short welds. All the even-numbered sheets are welded using a second serpentine welding pattern that includes a plurality of long welds and a plurality of short welds, such that the long welds of the second serpentine welding pattern are shifted from the long welds of the first serpentine welding pattern. When a sufficient number of sheets have been welded, the stack is trimmed to remove the short welds. The stack is expanded by pulling the sheets one from another to form the honeycomb core.