Precision Cutting Tool for Sharp Edges in Thick Sheets
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Solution Overview
Problem
Fine blanking methods struggle to produce workpieces with small corner radii and sharp edges from thicker sheets due to significant edge reduction and burr formation, limiting the functionality and economic viability of parts with complex geometries.
Innovation Solution
The method employs converging cutting geometries without corner radius, using a one-stage process with a circular geometry followed by a toothed geometry, where the first partial step cuts the addendum circle vertically and the second step cuts the blank spaces in the opposite direction, reducing pressure loads and minimizing rollover.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional fine blanking is used for workpieces with small corner radii and greater sheet thickness, then manufacturing capability is maintained, but edge reduction and burr formation increase significantly
Solution Approach 1:
The cutting process is divided into two sequential partial steps: first cutting the addendum circle structure in vertical direction, then cutting out the blank spaces between teeth in opposite direction. This segmentation allows each cutting geometry to be optimized independently, reducing edge reduction and burr formation while enabling manufacturing of complex geometries with small corner radii
Solution Approach 2:
The patent applies counter cutting where the second cutting punch removes material in the opposite direction to the first cut. This inversion of cutting direction compensates for edge reduction and burr formation, achieving superior edge quality and enabling production of sharp-edged interlocking parts that would otherwise be impossible with conventional single-direction cutting
2Reliability
If cutting path geometry includes small corner radii and sharp edges, then part functionality is improved, but fine blanking process becomes more difficult
Solution Approach 1:
The complex cutting path is segmented into two distinct operations: circular geometry cutting followed by toothed geometry cutting. Each segment handles specific geometric features, allowing sharp edges and small corner radii to be achieved without overwhelming the fine blanking process
Solution Approach 2:
The patent changes cutting parameters between the two partial steps, including cutting direction (vertical then opposite), punch geometry (circular then toothed), and sequencing. These parameter changes enable the process to handle complex geometries with small corner radii while maintaining fine blanking quality and part functionality
3Device complexity
If single-stage fine blanking is used, then process simplicity is maintained, but edge reduction and rollover are significant
Solution Approach 1:
The single-stage fine blanking process is segmented into two partial steps within one pressing operation. The first punch cuts the addendum circle, the second punch cuts the blank spaces between teeth in opposite direction. This segmentation reduces edge reduction and rollover while maintaining process simplicity as a one-stage arrangement
Solution Approach 2:
The second cutting punch operates in the opposite direction to the first punch, creating counter cutting action. This inversion compensates for edge reduction and rollover from the first cut, achieving superior edge accuracy while keeping the process structure simple with only one pressing cycle
Data Source
AI summary
A method and tool for producing workpieces with small corner radii in relation to the cutting thickness and with greatly reduced draw-in by precision cutting in a precision cutting tool includes clamping the workpieces between two tool parts consisting of a respective top and bottom cutting dies and of a top and a bottom cutting punch. The workpiece is machined in a one-stage arrangement in at least two successive cutting sequences in different cutting directions with the following partial steps: (A) cutting out a semifinished product, matched to the workpiece geometry, in a first cutting operation in a vertical working direction with slight draw-in, and (B) finish cutting of the semifinished product, produced in step (A), in at least one further cutting operation in a working direction opposed to step (A), wherein the draw-in of partial step (A) is filled again at least in the corner region.