Blanking Punch Engagement Structure for Safe Retraction
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Solution Overview
Problem
High-strength sheet metal, particularly multi-layer sheets, require high retraction forces for punching tools, which can lead to die brittleness and tearing issues when removing the punch, especially when working with different materials like aluminum and steel.
Innovation Solution
A punch design with a first section and a second section featuring a cutting edge, where the second section has a circumferentially arranged engagement section that allows for easy removal of the punch using a tool, reducing the risk of tearing by providing a stable and precise pulling mechanism, often utilizing a thread or other engagement elements for efficient extraction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If high retraction forces are applied to remove the punch from multi-layered high-strength sheet metal, then the punch can be withdrawn from the workpiece, but the punch may break off due to its brittleness
Solution Approach 1:
The punch is divided into multiple sections: a first section with a cutting edge for punching, a second section with an engagement element for tool attachment, and an intermediate section. This segmentation allows the removal tool to engage the punch at a location away from the brittle cutting edge, enabling safe extraction without applying stress to the fragile portion of the punch.
Solution Approach 2:
A separate removal tool is introduced as an intermediary device between the operator and the punch. This tool engages with the engagement element on the punch and provides a mechanical advantage system that allows controlled extraction without directly applying high forces to the brittle punch structure.
2Productivity
If conventional punching tools are used on multi-layered sheet metal with different materials, then punching can be performed, but the different layers exhibit different flow behavior causing punching difficulties
Solution Approach 1:
The punch design incorporates a specific geometry where the first section has a cutting edge optimized for shearing, while the second section has an engagement element optimized for tool attachment. The intermediate section provides a transition zone. This local differentiation of properties allows the punch to perform its cutting function effectively while being compatible with removal tools for extraction from difficult multi-material workpieces.
3Strength
If the punch is designed to be short relative to its diameter, then tearing is prevented through the basic shape, but the engagement section must be precisely positioned for stability
Solution Approach 1:
The engagement element is pre-positioned on the punch at a predetermined location in the intermediate section, away from the cutting edge. This preliminary positioning ensures that when the removal tool engages the punch, the force is applied at an optimal location that maintains punch stability and prevents tilting or misalignment during extraction, thereby preventing tearing.
Data Source
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Figure 4~6
AI summary
The invention relates to a blanking punch which extends from a first portion to a second portion along a blanking direction, wherein the second portion has a cutting edge, and wherein an engaging portion is provided/designed between the first portion and the second portion, said engaging portion enabling the blanking punch to be removed from a workpiece counter to the blanking direction.