Threaded Blanking Punch Extraction for High-Force Sheet Blanking
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Solution Overview
Problem
High-strength metal sheets, particularly multilayer sheets with different materials like aluminum and steel, require high forces for blanking, leading to a risk of the blanking punch breaking off due to brittleness, as existing tools are not designed to handle the varying flow properties effectively.
Innovation Solution
A blanking punch with a unique design featuring a first portion and a second portion with a cutting edge, where an engaging portion allows for removal from the workpiece using a separate tool, providing stability and avoiding breakage through a circumferential engaging element, such as a thread or groove, which converts tangential force into a force counter to the blanking direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If high-strength metal sheets are blanked using conventional blanking punches, then the blanking operation can be performed, but the blanking punch is at risk of breaking off due to the high forces required and the brittleness of the punch material
Solution Approach 1:
The blanking punch is divided into a working portion (with cutting edge) and a separate engagement portion (with thread). This segmentation allows the working portion to be optimized for cutting while the engagement portion provides a secure attachment point for extraction, preventing the punch from breaking under high blanking forces.
Solution Approach 2:
A threaded engagement portion acts as an intermediary element between the blanking punch and the extraction tool. This intermediary provides a secure mechanical connection that allows controlled extraction of the punch after blanking, eliminating the risk of punch breakage during removal.
2Ease of operation
If high withdrawal forces are applied to remove the blanking punch after blanking, then the punch can be extracted from the workpiece, but the blanking punch may break off due to its brittleness
Solution Approach 1:
The threaded engagement portion is prepared in advance on the blanking punch, creating a pre-configured extraction mechanism. This preliminary action allows the punch to be easily removed after blanking by simply engaging an extraction tool with the thread, eliminating the need for high withdrawal forces that could cause breakage.
3Reliability
If the blanking punch is designed to be short relative to its diameter, then breaking off is avoided, but the cutting edge geometry must be optimized
Solution Approach 1:
By segmenting the punch into working and engagement portions with a clear geometric transition, the design allows the working portion to maintain optimal cutting edge geometry while the engagement portion provides structural stability. The threaded portion acts as a structural reinforcement that prevents breakage without interfering with cutting performance.
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 efficient and cost-effective removal of the blanking punch from the workpiece without jamming, reducing the need for high-force tools and minimizing wear, while maintaining the quality of the blanked hole with precise control over extraction forces.
Implementation Method 1
the engaging portion has at least one circumferentially arranged engaging element that is oriented in an inclined manner along the longitudinal axis of the blanking punch... a circumferential force that is applied to the engaging portion by a tool and acts on the engaging portion, or on the at least one engaging element, substantially tangentially and transversely to the longitudinal axis is converted or diverted into a force that acts on the blanking punch counter to the blanking direction
Data Source
AI summary
A blanking punch which extends from a first portion to a second portion along a blanking direction is provided. The second portion has a cutting edge. An engaging portion is provided/designed between the first portion and the second portion. The engaging portion enables the blanking punch to be removed from a workpiece counter to the blanking direction.