Projectile Shell Imbalance Reduction via Rotational Axis Calculation
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Solution Overview
Problem
Current methods for producing projectile casings, especially medium and large caliber bullets, result in significant static and dynamic unbalance due to limitations in machining the inner contour near the mouth hole, leading to inconsistent geometry and increased spread of impact points, which are difficult to compensate for reliably without subjective human intervention and resulting in inhomogeneous wall thickness and potential disintegration issues.
Innovation Solution
A method that uses mathematical principles to calculate a modified axis of rotation, allowing for precise mechanical processing of the outer contour to reduce unbalance by adjusting wall thickness evenly, eliminating the need for subjective grinding and ensuring the axis of rotation aligns with the main longitudinal axis of inertia to minimize residual imbalance within specified tolerances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If manual grinding is used to compensate for imbalance, then the unbalance can be reduced, but the wall thickness becomes inhomogeneous and may fall below minimum requirements
Solution Approach 1:
The invention performs preliminary measurement of the inner contour geometry and calculates the optimal grinding strategy before any material removal. This allows planning the material removal to achieve balance while maintaining minimum wall thickness requirements, avoiding the trial-and-error approach that leads to over-grinding and thin walls.
Solution Approach 2:
The system uses measured data from the inner contour geometry to provide feedback for calculating the precise grinding strategy. The measurement results feed into the control algorithm that determines where and how much material to remove, creating a closed-loop process that ensures both balance and wall thickness requirements are met.
2Reliability
If conventional manual grinding is used, then operator experience can compensate for imbalance, but the process is not reliable and depends on subjective skills
Solution Approach 1:
The invention replaces the manual mechanical grinding process with an automated system that uses measurement devices and control algorithms. The subjective operator skill is substituted with objective measurement data and automated calculation, making the process reliable and repeatable while requiring sophisticated measurement and control equipment.
Solution Approach 2:
The system performs self-measurement of the inner contour geometry and self-calculation of the optimal grinding strategy. The process automatically determines the imbalance and calculates the correction without human intervention, making the system self-sufficient and eliminating dependence on operator experience.
3Manufacturing precision
If material is removed by grinding at one location, then imbalance is compensated, but the casing wall thickness is significantly reduced locally
Solution Approach 1:
The invention applies material removal only where necessary based on the calculated imbalance, rather than uniform grinding. The grinding strategy is localized to specific areas that need correction, minimizing total material removal while achieving the required balance tolerance.
Solution Approach 2:
Instead of removing excessive material through manual trial-and-error grinding, the system performs partial action by calculating the precise amount of material to remove. This avoids over-grinding and ensures that only the necessary minimum material is removed to achieve balance.
Data Source
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AI summary
The invention relates to a method for reducing an imbalance of a projectile shell. The projectile shell has a body (1) which has a recess (4). As a result of this recess (4), the body is provided with an inner wall (2) and an outer wall (3). In addition, a mouth opening (6) is provided, which is connected to the recess (4). A centre axis (5) is now calculated from the outer geometrical shape of the projectile shell and a measurement is then performed to ascertain an imbalance of the projectile shell. On the basis of the measured imbalance, an axis (8) that is modified in relation to the centre axis (5) is then calculated, and the body (1) is rotated about the modified axis (8) on the basis of the calculated modified axis (8). As the body (1) is rotated in this way, the projectile shell is machined to eliminate the imbalance as far as possible.