Abrasive Jet Apparatus for Machining Rifling Grooves in Gun Barrels
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Solution Overview
Problem
Current methods for machining rifling grooves in refractory metal and ceramic-lined gun barrels are inefficient, causing rapid tool wear, poor surface finish, and uneven surfaces, and fail to accommodate advanced gun barrel designs with varying rifling twist pitch angles.
Innovation Solution
An abrasive jet apparatus that uses a mixture of pressurized liquid and abrasive particles, directed at a precise angle, to machine hard surfaces and change bore diameters, allowing for precise control of groove width and depth, and accommodating various rifling twist pitches.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional machine tools are used to machine rifling grooves in refractory metals, then the grooves can be formed, but rapid tool wear occurs due to the strength and temperature resistance of the refractory metals
Solution Approach 1:
The patent replaces traditional mechanical machining tools with an abrasive waterjet system that uses high-pressure liquid and abrasive particles to erode and remove material. This substitution eliminates direct mechanical contact between cutting tools and the refractory metal workpiece, thereby preventing rapid tool wear while maintaining efficient material removal capability
Solution Approach 2:
The invention employs a high-pressure hydraulic system to deliver abrasive particles to the workpiece surface. The abrasive waterjet apparatus uses pressurized liquid to transport and accelerate abrasive particles, enabling effective machining of refractory metals without the tool wear problems associated with conventional mechanical cutting tools
2Manufacturing precision
If electron discharge machining (EDM) is used to machine rifling grooves in refractory metals, then the grooves can be formed with good precision, but the process is very slow
Solution Approach 1:
The patent replaces the electrical discharge process with a mechanical abrasive erosion process using high-pressure waterjet. This substitution enables faster material removal rates while maintaining the ability to achieve precise groove dimensions through controlled abrasive particle impact and erosion
3Productivity
If conventional waterjet machining is used with nozzles operated at right angles to the machined surface, then material removal can be achieved, but the nozzles are too large (1'' or more in diameter) to be used inside small bores
Solution Approach 1:
The invention segments the waterjet system into multiple smaller nozzle units that can be individually positioned and directed at various angles within the bore. This segmentation allows the system to access and machine small bores effectively while maintaining high material removal rates through coordinated operation of multiple jet streams
Solution Approach 2:
The patent transitions from conventional single-direction (right-angle) jet impingement to multi-directional jet delivery at shallow angles to the target surface. This dimensional change in jet orientation enables access to confined spaces within small bores while maintaining effective material removal through angled abrasive particle impact
4Strength
If refractory metal liners are explosively bonded to the main barrel, then the liners can be attached, but an uneven surface and variable liner thickness are left along the length of the barrel
Solution Approach 1:
The patent replaces mechanical and explosive bonding processes with direct abrasive waterjet machining of the liner material. This substitution enables precise control of liner thickness and surface uniformity through controlled material removal, while maintaining strong attachment by machining the liner in its bonded state rather than attempting to achieve uniformity during the bonding process itself
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 abrasive jet apparatus effectively machines rifling grooves and changes bore diameters with high accuracy and speed, reducing tool wear and improving surface finish, enabling the use of advanced gun barrel designs.
Implementation Method 1
an abrasive jet comprising a liquid and abrasive particle mixture
Implementation Method 2
directs an abrasive jet... to machine hard surfaces
Data Source
AI summary
An abrasive jet apparatus configured to machine features into an inner diameter of bored structures. In the abrasive jet apparatus, an abrasive mixture of pressurized liquid and abrasive particles is propelled as an abrasive jet in a direction other than the direction in which the abrasive jet apparatus extends. The abrasive jet apparatus may be implemented in an automated boring system and boring method for machining rifling grooves and other features into bored structures. The boring system and boring method use an iterative process of mapping a target surface of the bored structure and adjusting parameters of the boring system in between successive passes of the abrasive jet on the target surface.