Polymer Ammunition Cartridge with Metal Insert
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Solution Overview
Problem
Conventional ammunition cartridge casings made from brass are heavy, expensive, and hazardous, while plastic alternatives have failed to provide reliable, safe, and effective ballistic performance, often resulting in inconsistent pressures and structural failures during firing.
Innovation Solution
A method of producing a lightweight ammunition cartridge using metal injection molding, where a stainless steel insert is created through a process involving a mold, powdered metal, and binding agents, and then bonded to a polymeric middle body, featuring a cylindrical design with a primer recess and flange, to enhance structural integrity and compatibility with existing weaponry.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If conventional brass cartridge casings are used, then structural strength and reliability are ensured, but weight increases and cost increases
Solution Approach 1:
The cartridge casing is constructed as a composite structure with a polymeric outer casing and a metal insert positioned at the base. The metal insert provides structural reinforcement for withstanding firing pressures, while the polymeric material reduces overall weight. This composite approach resolves the contradiction by combining materials with complementary properties.
2Weight of moving object
If plastic cartridge casings are used, then weight is reduced, but reliability and ballistic performance deteriorate due to inconsistent pressures and structural failures
Solution Approach 1:
The metal insert provides structural rigidity and consistent pressure containment during firing, eliminating the reliability issues of pure plastic casings. The controlled geometry of the metal insert ensures uniform pressure distribution and consistent ballistic performance while maintaining the weight advantages of polymeric construction.
3Ease of manufacture
If conventional brass cartridge casings are used, then manufacturing reliability is ensured, but cost increases and hazardous material handling is required
Solution Approach 1:
The polymeric casing can be manufactured using injection molding techniques, which are cost-effective and safe compared to brass forming processes. The metal insert is integrated into the polymeric structure, combining the manufacturing advantages of plastic with the performance characteristics of metal, thereby reducing both cost and hazard while maintaining reliability.
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 solution provides a lightweight, reliable, and cost-effective ammunition cartridge with improved structural integrity and consistent ballistic performance, addressing the limitations of traditional brass casings and previous plastic alternatives.
Implementation Method 1
providing a mold of the substantially cylindrical insert to form a substantially cylindrical insert mold; providing a feedstock comprising a powdered metal and a first binding agent and a second binding agent; injection molding the feedstock into the substantially cylindrical insert mold to form an substantially cylindrical insert having a first size; debinding the substantially cylindrical insert to remove the first binding agent; and sintering the substantially cylindrical insert to remove the second binding agent and form a finished substantially cylindrical insert having a second size
Implementation Method 2
sintering the substantially cylindrical insert to remove the second binding agent and form a finished substantially cylindrical insert having a second size
Data Source
AI summary
One embodiment of the present invention provides a polymeric ammunition cartridge and methods of making and using the same. The cartridge includes a substantially cylindrical insert connected to a substantially cylindrical polymeric middle body. The substantially cylindrical insert includes a top surface opposite a bottom surface and a substantially cylindrical coupling element that extends from the bottom surface, a primer recess in the top surface that extends toward the bottom surface, a primer flash hole positioned in the primer recess to extend through the bottom surface, and a flange that extends circumferentially about an outer edge of the top surface. The substantially cylindrical polymeric middle body includes a substantially cylindrical polymeric bullet-end and a substantially cylindrical polymeric coupling end connected by a powder chamber, wherein the substantially cylindrical polymeric coupling end extends over the substantially cylindrical coupling element and covers a circumferential surface of the primer flash hole.