Fine Blanking Preforming to Prevent Edge Rollover
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Solution Overview
Problem
Fine blanking techniques often result in edge rollover and cutting burr, particularly in corner areas, leading to reduced functionality and the need for thicker materials, which increases production costs and material waste.
Innovation Solution
A method involving preforming the flat strip before cutting, using a preforming element to create a mirror-inverted material volume on the rollover side, supported by a coining stamp or ejector with specific preforming angles, to prevent edge rollover and maintain sharp edges without material shifting along the cutting line.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If fine blanking is performed on flat strip material, then cutting precision is improved, but edge rollover occurs reducing functionality
Solution Approach 1:
The invention applies preliminary action by pre-forming the material before cutting. A preforming element creates a negative rollover geometry (mirror-inverted material volume) in the flat strip before the actual cutting process. This preliminary deformation prepares the material so that when cutting occurs, the pre-formed geometry compensates for the rollover that would normally occur, resulting in sharp edges without requiring post-processing.
Solution Approach 2:
The invention applies preliminary anti-action by creating a preformed geometry that is the opposite (mirror-inverted) of the expected rollover. The preforming element generates material volume with a contour that corresponds to the negative of the anticipated edge rollover. This counteracts the harmful rollover effect during cutting, preventing the loss of sharp edges and functional surfaces.
2Shape
If thicker material is used to compensate for rollover, then functionality is maintained, but material consumption increases
Solution Approach 1:
Instead of using thicker material as a compensation strategy, the invention uses preliminary action to pre-form the exact geometry needed. The preforming element creates a negative rollover volume that precisely compensates for expected material displacement during cutting. This allows thin-walled parts to maintain their functional surfaces without requiring additional material thickness, thereby reducing material consumption.
Solution Approach 2:
The invention changes the geometric parameters of the material before cutting by pre-forming it with specific contours and angles. The preforming element is designed with specific preforming angles and geometry that correspond to the negative of the expected rollover. This parameter transformation allows the material to undergo cutting without losing its sharp edges, eliminating the need to increase material thickness.
3Shape
If additional machining operations are performed to remove rollover, then edge quality is improved, but production costs increase
Solution Approach 1:
The invention eliminates the need for additional machining operations by performing the edge quality preparation in advance. The preforming element creates the negative rollover geometry before cutting, so that when the cutting occurs, the edges are already prepared to remain sharp. This preliminary action integrates the edge quality function into the forming process itself, eliminating separate machining steps and reducing device complexity.
Solution Approach 2:
The invention merges the preforming and cutting operations into an integrated process. The preforming element is part of the same tooling system that performs cutting, combining two previously separate operations (pre-forming to prevent rollover and cutting to create the part) into a single coordinated process. This merging eliminates the need for separate machining operations and reduces overall device 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
Enables the production of fine blanking parts with sharp edges and reduced material usage, minimizing additional machining operations and material loss, while maintaining functional surfaces even at thinner thicknesses.
Implementation Method 1
carrying out, at the untreated clamped flat strip before the cutting starts, a negative with regard to the cutting direction preforming with a preforming element in the direction opposite to the cutting direction that corresponds to the expected edge rollover into the cutting die with regard to size and geometry at cutting including an allowance and generates a material volume at the side of the rollover in a mirror-inverted form
Data Source
AI summary
A method and a device for the production of a stamping with an enlarged functional surface, for example, fine blanking a workpiece out of a flat strip, wherein the flat strip is clamped between an upper part including a shearing punch, a pressure pad for the shearing punch, a V-shaped projection arranged on the pressure pad and an ejector which is pressed into the flat strip, and a lower part including a cutting die and an ejector. Edge rollover is avoided by preforming, before cutting begins, a negative with regard to the cutting direction with a preforming element in the direction opposite to the cutting direction that corresponds to the expected edge rollover into the cutting die with regard to size and geometry at cutting, generating a material volume at the side of the rollover in a mirror-inverted form. During cutting, the preformed area is supported by the preforming element.