Long Cartridge Case Forming With Modified Hooker Extrusion
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Solution Overview
Problem
Existing methods for forming long cartridge cases using multiple backward extrusions result in high tool stress and poor tool life, necessitating a less stressful tube forming process.
Innovation Solution
A single backward extrusion combined with modified Hooker extrusions is used to form a hollow part for a long cartridge case, maintaining the external diameter and reducing forming loads and energy consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multiple backward extrusions are used to form long cartridge cases, then the desired wall thickness and length can be achieved, but high tool stress and poor tool life result
Solution Approach 1:
The forming process is segmented into two distinct operations: first a single backward extrusion to create the hollow form, then one or more Hooker extrusions to achieve the desired wall thickness. This segmentation allows each operation to be optimized independently, reducing the stress on tooling compared to multiple backward extrusions while still achieving the required precision.
Solution Approach 2:
Instead of using backward extrusion (which reduces internal diameter) to control wall thickness, the invention inverts the approach by using Hooker extrusion (which increases external diameter) to achieve the same goal. This inversion reduces the forming load and stress on the tooling while maintaining manufacturing precision for wall thickness.
2Manufacturing precision
If multiple backward extrusions are used to form long cartridge cases, then the desired wall thickness and length can be achieved, but excessive forming loads and energy consumption occur
Solution Approach 1:
The total forming operation is segmented into a single backward extrusion followed by Hooker extrusion(s). This segmentation reduces the cumulative forming load and energy consumption compared to multiple backward extrusions, while still achieving the desired wall thickness through the Hooker extrusion process.
Solution Approach 2:
The invention inverts the conventional approach by using Hooker extrusion (increasing external diameter) instead of repeated backward extrusion (reducing internal diameter) to control wall thickness. This inversion significantly reduces the forming load and energy consumption while achieving the same manufacturing outcome.
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
Improves tool life and allows the use of smaller, faster cold forming machines by reducing forming loads by 50% and energy consumption by 40%, while achieving the desired wall thickness and length.
Implementation Method 1
backward extrusions of an initially solid cylindrical blank
Implementation Method 2
Modified Hooker extrusions to obtain a desired wall thickness in the workpiece
Data Source
AI summary
A method of forming a closed end metal tube comprising cutting a blank from a solid round metal wire, backward extruding an axial hole in the blank to produce a hollow sidewall with a thickness, and reducing the sidewall thickness by using one or more Modified Hooker extrusions.