Punch Blade Segmentation for Seamless Elongated Holes
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Solution Overview
Problem
Conventional nibbling processes using punching presses often result in projection-shaped seams at the ends of overlapping holes due to the need for access openings and the inability to punch off inner side portions of cuttings, leading to incomplete cutting and seams in elongated holes.
Innovation Solution
A punch with first and second blade sections, where the blade sections are juxtaposed parallel to the feed direction, allowing for notching and punching edges to form elongated holes without seams by overlapping notches and punched holes, using a die with partitioned throughholes to guide the punch and die edges for precise cutting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a conventional punching die with rectangular transverse sectional shape is used to continuously punch holes, then productivity is improved, but projection-shaped seams are left at the ends of overlap areas
Solution Approach 1:
The punch is divided into multiple blade sections (first blade section, second blade section, third blade section) arranged in sequence along the feed direction. Each blade section performs a specific function: the first creates notches, the second punches out material, and the third completes the cutting. This segmentation allows continuous punching while eliminating seams at overlap areas by ensuring complete material removal at each stage.
2Ease of operation
If an access opening is formed beforehand to enable blade insertion, then the nibbling operation can start, but a projection-shaped seam is inevitably left at the end of the overlap area between the access opening and initial cutting
Solution Approach 1:
The first blade section performs preliminary notching action before the second blade section punches out the material. By creating notches at the edges of the access opening beforehand and then punching out the material between the notches, the system eliminates the projection-shaped seam that would otherwise form at the overlap area between the access opening and the initial cutting.
3Ease of manufacture
If the inner side portion of the cutting is punched out with a standard punch, then the cutting is completed, but a projection-shaped seam is left in the overlap area between the elongated hole and punched hole
Solution Approach 1:
The notching function of the first blade section and the punching function of the second blade section are merged into a single integrated punch structure. This merging ensures that the notches created by the first blade section and the punched holes created by the second blade section overlap perfectly, eliminating the projection-shaped seam that would form between separate elongated holes and punched holes when using a standard punch.
4Reliability
If the inner side portion of the cutting is left uncut due to downward bending, then the die is protected from interference, but the cutting is incomplete and seams are formed
Solution Approach 1:
The solution addresses the downward bending issue by introducing a third blade section that operates in a different spatial arrangement. The third blade section is positioned to cut the inner side portion of the cutting that was previously left uncut, ensuring complete material removal without interfering with the die. This dimensional arrangement allows complete cutting while protecting the die from interference by downwardly bent material.
Data Source
AI summary
A punch includes first and second blade sections juxtaposed relative to each other in a direction parallel or substantially parallel to a feed direction of a sheet material. The first blade section protrudes downwardly from the second blade section with a step intervening therebetween and includes lower end edges on downstream and upstream sides of the feed direction, which define respective punching edges. The first blade section includes a lower end edge following the feed direction, which defines a first notching and punching edge. The notching and punching edge includes a portion intermediate of the feed direction representing a projecting shape. The second blade section includes a lower end edge on the upstream side, which defines a punching edge and also includes a lower end edge following the feed direction, which defines a notching and punching edge. The notching and punching edge is inclined gradually upwardly towards the upstream side.