Cartridge Case Cold Forming With Orbital Shear Trimming
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Solution Overview
Problem
Conventional methods for manufacturing brass cartridge cases are inefficient, involving multiple machines, high scrap ratios, energy-intensive annealing, and labor costs, with dimensional variations and machining-related issues leading to maintenance and recycling challenges.
Innovation Solution
A single forming machine is used to fully cold-form a rimless, solid-head cartridge case from metal wire stock, eliminating secondary machining and annealing by forming the ejector groove without material removal, and using a novel orbital shear for end trimming to achieve a uniform edge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional strip stock method is used to manufacture cartridge cases, then cases can be formed through cupping and drawing, but the process produces high scrap ratio, requires energy for annealing, is slow, and occupies considerable floor space
Solution Approach 1:
The invention changes the material form from strip stock to solid wire stock, and changes the manufacturing method from hot working (cupping and drawing with annealing) to cold forming. This parameter change eliminates the need for annealing energy and significantly reduces scrap ratio while maintaining manufacturing feasibility
Solution Approach 2:
The invention extracts and eliminates the annealing step from the manufacturing process by using cold forming instead of hot working. This removal of the annealing step directly reduces energy consumption and simplifies the manufacturing process
2Manufacturing precision
If heavily drawn preform is produced from strip stock or wire, then the preform has an irregular edge on the open end, but traditional machining to create precise end surface creates scrap in particle, chip shaving and/or dust form
Solution Approach 1:
The invention replaces the traditional mechanical machining system (turning machines that produce chips and dust) with a cold forming system that shapes the preform directly. This substitution eliminates machining scrap generation while achieving the required dimensional precision through controlled plastic deformation
Solution Approach 2:
The invention changes the manufacturing approach from subtractive machining to additive/transformative cold forming. By changing the material state and forming method, the process achieves precise dimensions without removing material, thereby eliminating chip and dust generation
3Manufacturing precision
If case preforms are transferred from forming machines to turning machines, then dimensional variations are introduced, but multiple potential combinations of machines increase complexity and variability
Solution Approach 1:
The invention merges multiple separate operations (forming, trimming, and final shaping) into a single integrated cold forming machine. This consolidation eliminates the need for transferring preforms between different machine banks, thereby eliminating the dimensional variations and complexity associated with multiple machine combinations
4Manufacturing precision
If traditional machining operations are used to create ejector groove and trim ends, then precise dimensions can be achieved, but labor costs are involved and each machine must be monitored and maintained
Solution Approach 1:
The invention combines multiple machining operations (ejector groove formation, end trimming, and shaping) into a single automated cold forming process. This integration eliminates the need for separate machines and reduces labor involvement in monitoring and maintenance while maintaining dimensional accuracy through controlled forming parameters
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
The process enhances metallurgical properties, reduces the likelihood of cracking, and increases production capacity while minimizing labor, energy, and material usage, resulting in a more reliable and efficient manufacturing process.
Implementation Method 1
an orbital shear trimmer that shears the forward end of the preform to a uniform edge
Implementation Method 2
The case is fully cold formed from metal wire stock, typically brass, in a single forming machine
Implementation Method 3
The blank is upset and extruded to form early stages of a primer pocket, a tubular charge and bullet space
Data Source
Figure 1A~1I
Figure 2A
Figure 2B
AI summary
An improved cartridge case completely produced net shape on a progressive cold former that includes a trim to lengthy station with an internal shearing tool.