Angled Torsional Strips for Accurate Sheet Metal Folding
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Solution Overview
Problem
Existing methods for forming complex sheet materials into three-dimensional structures are limited by the need for expensive and complex tooling, accuracy issues in bending, and material integrity problems, particularly with less ductile materials like titanium and hardened steel, which restrict their use in high-precision applications.
Innovation Solution
Cutting elongated slots through sheet materials to create parallel strips angled obliquely along a fold line, allowing for plastic deformation via torsion rather than bending, which facilitates accurate and complex folding with minimal tooling and reduces stress concentrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If traditional bending methods are used to form sheet materials, then complex three-dimensional structures can be created, but manufacturing precision deteriorates due to tolerance stack up errors from bend to bend
Solution Approach 1:
The sheet material is divided into multiple parallel strips by cutting elongated slots, creating a segmented structure where each strip acts as an independent folding element. This segmentation allows each strip to fold independently along the fold line, eliminating the tolerance accumulation that occurs in traditional multi-bend processes while still achieving complex three-dimensional geometries.
Solution Approach 2:
The invention transitions from traditional bending (one-dimensional deformation) to torsional folding (three-dimensional deformation). By applying moment forces that create torsion in the strips rather than simple bending, the method achieves precise folding through a different dimensional mechanism, where the strips twist and fold simultaneously, maintaining accuracy across multiple folds.
2Manufacturing precision
If expensive and complex tooling is used to form sheet materials into three-dimensional structures, then manufacturing precision can be maintained, but device complexity increases
Solution Approach 1:
The invention extracts the folding function from complex traditional tooling by using simple moment forces applied to the segmented strips. Instead of requiring expensive, precision-machined dies and fixtures, the method uses basic mechanical elements that apply rotational forces to the strips, achieving high precision folding with minimal tooling complexity.
Solution Approach 2:
The method replaces expensive, complex, and durable tooling with simple, inexpensive, and potentially disposable fixtures or hands that apply moment forces. The focus shifts from creating precision through expensive equipment to achieving precision through the inherent properties of the segmented strip structure and simple force application.
3Strength
If traditional bending methods are used on less ductile materials like titanium and hardened steel, then material strength is maintained, but manufacturing capability deteriorates due to cracking and tearing
Solution Approach 1:
The invention changes the deformation parameter from bending stress to torsional stress. By applying moment forces that create torsion in the strips rather than bending the entire sheet, the method reduces stress concentrations that cause cracking in less ductile materials. The torsional deformation distributes stress more evenly along the strip length, enabling forming of titanium, hardened steel, and other high-strength materials without failure.
Solution Approach 2:
Segmenting the sheet into parallel strips isolates the deformation to narrow individual elements rather than the entire sheet. This segmentation reduces the overall stress and strain on less ductile materials, as each thin strip can tolerate torsional deformation without the stress concentrations that would cause cracking in traditional bending of thick, less ductile sheets.
4Device complexity
If simple bending machines are used to fold sheet materials, then device complexity is minimized, but manufacturing precision deteriorates due to accuracy issues in bending
Solution Approach 1:
The invention changes the deformation mechanism from simple bending to torsional folding by applying moment forces that create rotation in the strips. This dimensional change in the deformation mode allows simple machines to achieve high precision, as the torsional mechanism inherently provides better control and accuracy than traditional bending, even with minimal tooling complexity.
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 enables precise, cost-effective folding of a wide range of materials, including ductile and semi-ductile types, with improved material strength and reduced stress concentrations, allowing for complex geometries and efficient load transfer, while minimizing tooling costs and training requirements.
Implementation Method 1
The strips connect adjacent sections of sheet material and encourage the sheet material to fold at the fold line when said sheet is subjected to a moment force created by hand, fixture or simple machine. In this embodiment, the connecting strips undergo plastic deformation mainly via torsion rather than bending.
Data Source
AI summary
One embodiment described herein is a sheet of material 200 formed into accurate and high value structures by implementing a plurality of elongated slots 202 that are obliquely placed along a fold line 204 which create one or more strips 206 consisting of a length w, a width s and an angle f to said fold line 204. The strips 206 are put into a state of plastic deformation through torsion which is controlled via the combination of said length w, width s, and angle f elements to create accurate, unique, complex and high value products or forms. The embodiments described allow for a greater degree of freedom of sheet material types, a greater degree of sheet material thicknesses, while simplifying implementation. This and other embodiments are also enclosed.