Single-Piece Sheet Metal Bending for Springback Precision
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Solution Overview
Problem
Current methods for manufacturing metal components from sheet metal, such as gearbox forks and injector brackets, require separate parts and welding, leading to complex, costly, and stress-inducing processes with precision issues and risk of cracking when attempting to form single-piece components with complex geometries.
Innovation Solution
A method involving bending operations using a punch and die with specifically calibrated curved surfaces to counteract springback and reduce material stress, ensuring high precision and mechanical integrity by adjusting the radius of curvature based on material tensile strength and thickness, thereby eliminating the need for welding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional bending techniques are used to form bends in sheet metal components, then the component can be manufactured from a single piece of sheet metal, but the geometric and dimensional precision is insufficient and machining is required to meet tolerances
Solution Approach 1:
The patent modifies the bending process parameters by adjusting the punch radius (R1) and die radius (R2) based on the sheet thickness and material properties. Specific parameter ranges are defined: R1 = 0.5-2.0 times sheet thickness, R2 = 1.0-3.0 times sheet thickness. These parameter optimizations enable direct formation of bends with required precision without subsequent machining.
Solution Approach 2:
The patent applies preliminary actions by pre-calculating and pre-setting the correct punch and die radii before bending begins. The neutral axis position is determined in advance, and the tooling is configured accordingly to compensate for springback and achieve the target geometry directly in the bending operation.
2Shape
If conventional bending techniques are used to form complex bends in sheet metal, then the component geometry can be achieved, but the mechanical characteristics of the material are reduced and cracking risk increases
Solution Approach 1:
The patent optimizes bending parameters including punch radius R1 = 0.5-2.0×sheet thickness and die radius R2 = 1.0-3.0×sheet thickness. These specific parameter ranges control the deformation zone size and stress distribution, enabling complex geometries to be formed while maintaining material strength and avoiding cracking.
Solution Approach 2:
The patent applies preliminary anti-action by designing the punch and die with radii that pre-compensate for springback and stress concentration. The tooling geometry is configured in advance to counteract the material's tendency to spring back and to distribute stresses uniformly, preventing cracking before it can occur during the bending operation.
3Ease of manufacture
If separate parts are manufactured and welded together, then the component can be assembled, but the manufacturing process becomes complex and costly
Solution Approach 1:
The patent merges multiple separate manufacturing operations into a single integrated bending process. By optimizing the punch and die radii, the invention enables complex multi-bend geometries to be formed directly from a single sheet metal piece in one operation, eliminating the need to manufacture separate parts and perform welding operations.
Solution Approach 2:
The patent creates a universal bending solution that can handle various bend geometries and angles by using adjustable punch and die radii within specified ranges. This multi-functional approach allows a single bending setup to produce different component geometries, replacing multiple specialized manufacturing processes.
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
Enables the production of metal components with high dimensional accuracy and reduced material stress, enhancing mechanical performance and reducing the risk of cracking, while simplifying the manufacturing process by forming components from a single sheet metal piece.
Implementation Method 1
counteracting the springback of the material after bending
Implementation Method 2
at least one bending operation consisting in urging the sheet metal piece against a die with a punch
Implementation Method 3
reducing the stresses on the material during bending
Data Source
Figure 1
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AI summary
For manufacturing metal components, at least one operation of bending a sheet metal piece is carried out by urging the sheet metal piece against a die (50) with a punch (52). The working surface (54c) of the die has a radius of curvature (rM) greater than the radius of curvature (rl) of the theoretical extrados surface (SE) of the bent portion (P) to be obtained. The radius of curvature (rM) of the working surface (54c) of the die is calculated from the radius of curvature (rE) of the theoretical extrados surface (SE) of the bent portion (P) to be obtained taking into account a correction factor (k) dependent on the tensile strength of the material of the sheet metal piece, on the bending angle (α) of the bent portion (P) to be obtained and on the thickness (s) of the sheet metal piece.