Gun Drill Centerline Deviation Control via Acoustic Feedback
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Solution Overview
Problem
Conventional gun drilling methods experience unpredictable centerline deviations and excessive twisting due to high length-to-diameter ratios, leading to inaccuracies in forming elongated bores in workpieces, especially when multiple bores are created.
Innovation Solution
A method involving real-time monitoring of the drill's azimuthal orientation and distance from the workpiece's surface using acoustic signals, with strategic application of axial impulse forces to adjust the drill's path and maintain alignment, utilizing piezo-electric stacks for precise control and minimizing centerline deviations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If conventional gun drilling is used with high length-to-diameter ratios, then elongated bores can be formed, but centerline deviations become unpredictable and excessive twisting occurs
Solution Approach 1:
The system continuously monitors the drill's azimuthal orientation using acoustic signals and compares it against the desired bore path. Based on this feedback, the control system applies corrective axial impulse forces to steer the drill back toward the projected path, eliminating unpredictable centerline deviations while maintaining the ability to form elongated bores
Solution Approach 2:
The patent replaces conventional passive mechanical drilling with an active controlled system that uses acoustic signal monitoring and piezoelectric actuation. This substitution enables real-time detection of drill orientation and application of corrective forces, transforming an uncontrollable mechanical process into a precisely controlled one that maintains accuracy despite high length-to-diameter ratios
2Manufacturing precision
If axial impulse forces are applied to correct drill path deviations, then bore centerline accuracy improves, but the system complexity increases
Solution Approach 1:
The patent introduces acoustic signals as an intermediary medium to indirectly measure drill orientation without requiring direct mechanical sensors on the drill itself. This intermediary approach simplifies the overall system by using non-contact measurement through the workpiece material, reducing the complexity of direct mechanical sensing while maintaining precision control capability
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
This approach significantly reduces centerline deviations, ensuring the drill stays within a tolerance value and maintains a precise bore path, even in long drills with high length-to-diameter ratios, improving the accuracy and consistency of bore formation.
Implementation Method 1
The step of applying an impulse force includes providing a piezo-electric stack that is axially coupled to the drill, and energizing the piezo-electric stack
Implementation Method 2
monitoring an azimuthal orientation of the drill head in a bottom of the bore... monitoring includes measuring an acoustic signal generated by the drill head in the bore over time
Data Source
AI summary
A method of forming a bore through a workpiece with a drill by monitoring drill orientation and bore position; and adjusting drill path as necessary. Adjusted the drill path includes selectively applying an axial impulse to the drill when the drill is in a designated azimuthal orientation. Drill orientation and bore position are monitored with an acoustic transmitter and receiver disposed adjacent an outer surface of the workpiece. The acoustic transmitter and receiver are moved at the same rate at which the drill axially progress through the workpiece, so that they are aligned with the bottom of the bore.