CNC Drill Feed Oscillation for Chip Extraction in Hybrid Materials
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Solution Overview
Problem
Machining of material combinations involving metallic and non-metallic materials is challenging due to differing material characteristics, particularly in drilling processes, where existing methods like peck drilling increase cycle time and are prone to debris packing, and vibration-assisted drilling requires costly dedicated equipment.
Innovation Solution
An automated drilling system that induces a numerically controlled oscillating motion superimposed over a spindle feed rate, using existing machine tools to improve chip formation and extraction efficiency, reduce production time, and extend tool life by fragmenting metallic chips into small triangular shapes, facilitating hybrid drilling operations between conventional and vibration-assisted techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If peck drilling is used to machine material combinations, then chip extraction is improved, but cycle time increases and debris packing occurs
Solution Approach 1:
The patent applies vibration-assisted drilling by superimposing an oscillating motion on the drilling process. The controller induces a numerically controlled oscillating motion that creates intermittent cutting conditions, preventing chip packing in the flutes while maintaining continuous forward feed. This resolves the contradiction by eliminating debris packing without requiring periodic retraction, thus reducing cycle time compared to traditional peck drilling.
Solution Approach 2:
The patent implements periodic oscillation of the drill bit during drilling. The controller programs an oscillating motion that periodically varies the cutting depth, creating intermittent chip formation and extraction. This periodic action prevents chip packing while maintaining continuous advancement, solving the contradiction between chip extraction efficiency and cycle time.
2Productivity
If vibration-assisted drilling is used to improve chip formation, then drilling efficiency is improved, but equipment cost increases due to dedicated vibration drills
Solution Approach 1:
The patent makes the existing CNC drilling system multi-functional by adding vibration capability through the controller. The same drilling apparatus can perform both conventional drilling and vibration-assisted drilling by programming different motion patterns. This eliminates the need for dedicated vibration drills, reducing equipment cost while maintaining improved drilling efficiency.
Solution Approach 2:
The patent replaces dedicated mechanical vibration generation equipment with a programmable control system that induces oscillating motion through the existing feed mechanism. The controller programs the feed axis to superimpose oscillating motion on the axial feed, substituting complex mechanical vibration systems with a software-controlled approach that uses existing hardware.
3Object-generated harmful factors
If oscillating motion is superimposed on axial feed rate, then chip extraction is improved, but control complexity increases
Solution Approach 1:
The patent uses the existing CNC controller's feedback systems to monitor and adjust the oscillating motion parameters. The controller programs numerically controlled oscillating motion with specific frequencies and amplitudes, using the machine's feedback mechanisms to maintain precise control. This manages control complexity by leveraging existing feedback infrastructure rather than adding new control systems.
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 system achieves reduced drill process time, improved hole quality, decreased drill thrust and temperature, reduced lubrication needs, and extended tool life by efficiently managing chip formation and extraction through programmable oscillation parameters, integrating seamlessly with existing hardware.
Implementation Method 1
inducing a numerically controlled oscillating motion superimposed over the numerically controlled axial feed rate
Data Source
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AI summary
A computer-implemented drilling method includes steps of: (1) drilling a workpiece using a power drill; advancing the power drill along a feed axis according to a numerically controlled axial feed rate using a tool drive; and (3) inducing a numerically controlled oscillating motion of the power drill using the tool drive that is superimposed over the numerically controlled axial feed rate.