Bevelled Punch Stamp Radial Force Sheet Metal Evenness
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Solution Overview
Problem
Punching sheet metal in existing machines leads to deformation and inaccuracies due to tensile stress, especially in elongated hole-like tools, and current solutions like grinding or straightening are costly and limited in applicability.
Innovation Solution
A die and stamp combination with a bevel on the stamp's end face, increasing the clearance and applying radial forces to counteract stress, maintaining evenness and reducing deformation during punching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional punching is performed with standard stamp and die clearance, then punching operation is simple and fast, but tensile stress causes sheet metal deformation and upward bending
Solution Approach 1:
The invention changes the geometric parameters of the stamp by adding a bevel to the end face. This bevel modifies the stress distribution parameters during punching, transforming the harmful tensile stress into radial compressive stress that counteracts the upward bending tendency of the sheet metal, thereby maintaining sheet evenness without reducing punching speed
Solution Approach 2:
The bevel is applied locally at the end face of the stamp rather than modifying the entire stamp structure. This localized geometric modification concentrates the stress-altering effect precisely where needed (at the punch-s sheet metal interface) while keeping the rest of the punching system simple and efficient
2Manufacturing precision
If die is grinded in convex manner to reduce deformation, then sheet metal evenness is improved, but production becomes elaborate and costly
Solution Approach 1:
Instead of modifying the die (as in conventional convex grinding), the invention inverts the approach by modifying the stamp. The bevelled stamp applies radial compressive stress from above, achieving the same evenness effect without requiring complex convex grinding of the die, thereby simplifying manufacturing
Solution Approach 2:
The invention changes the stamp geometry parameter by adding a bevel, which fundamentally alters the stress application method. This parameter change achieves sheet metal evenness through a simpler manufacturing process compared to convex die grinding
3Manufacturing precision
If sheet metal is processed on straightening machines to remove stresses, then evenness is restored, but additional machines and process steps are required
Solution Approach 1:
The invention performs the stress-balancing action preliminarily during the punching operation itself. The bevelled stamp applies radial compressive stress that prevents upward bending as the punch occurs, eliminating the need for subsequent straightening operations and reducing the overall process complexity
4Manufacturing precision
If clearance between stamp and die is increased to reduce stress, then deformation is reduced, but punching effectiveness decreases
Solution Approach 1:
The invention changes the stress distribution parameters through the bevel geometry rather than simply increasing clearance. The bevel angle and height are optimized to generate sufficient radial compressive stress to counteract upward bending while maintaining adequate clearance for punching effectiveness
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 bevel design effectively balances stresses in the sheet metal, producing even, strain-free punched sheets with improved accuracy and reduced tool wear, applicable to high-grade punching operations.
Implementation Method 1
Due to the bevel, radial forces are brought into the sheet metal when the stamp penetrates into the sheet metal. The radial forces are suitable for counteracting the stresses in the sheet metal
Data Source
AI summary
A method for punching and straightening sheet metal in a punching machine includes the steps that a die is accommodated in a first tool holder of a punching machine, an upper tool part with a stamp is accommodated in a second tool holder, and a sheet metal is positioned between the stamp and the die at a location to be machined. The stamp comprises an end face at an end opposite to an accommodated end of the upper tool part, wherein a bevel has an angle and a height extending from a rim of the face to the end face. Then, a punching operation is performed by the stamp, wherein radial forces are simultaneously applied to the sheet metal during cutting so that an evenness of the sheet metal is maintained even at high grades of punching.