Drilling-Countersinking Vibration Control for Clatter-Free Bores
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Solution Overview
Problem
The existing method for machining workpieces using drilling and countersinking tools experiences undesirable axial clattering, leading to stress on the tool and clatter marks on the surface, which affects dimensional accuracy.
Innovation Solution
The method involves superimposing the axial feed movement with an axial vibration, lowering the frequency to a final machining frequency when reaching a predefined frequency lowering position, and maintaining or increasing the amplitude until the counterbore terminal position is reached, thereby reducing clattering and enhancing dimensional accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If axial vibration is superimposed on axial feed movement to break chips, then chip breaking is improved, but axial clattering and clatter marks occur
Solution Approach 1:
The patent applies dynamics by varying the vibration frequency during the machining process. The frequency is adjusted based on the axial position of the tool, being higher during drilling to break chips effectively, and lower during countersinking to prevent clatter marks on the surface. This dynamic adjustment resolves the contradiction between chip breaking and surface quality.
Solution Approach 2:
The patent changes the parameter of vibration frequency during the machining process. By lowering the frequency when reaching a predefined frequency lowering position and maintaining it at a final machining frequency, the system optimizes both chip breaking during drilling and surface quality during countersinking, eliminating axial clattering while preserving chip breaking effectiveness.
2Loss of substance
If high frequency axial vibration is used to break chips, then chip breaking is improved, but dimensional accuracy of bore and counterbore deteriorates
Solution Approach 1:
The patent uses dynamic frequency adjustment where high vibration frequency is applied during drilling for effective chip breaking, then the frequency is lowered during countersinking to improve dimensional accuracy. This temporal separation of frequency levels resolves the contradiction between chip breaking and precision.
Solution Approach 2:
The vibration frequency parameter is changed from a high initial frequency to a lower final machining frequency at a predefined position. This parameter change enables optimal chip breaking during drilling while achieving better dimensional accuracy during the countersinking operation.
3Shape
If axial vibration amplitude is decreased or canceled before reaching counterbore terminal position to smooth surface, then surface smoothing is improved, but axial clattering occurs
Solution Approach 1:
Instead of decreasing or canceling vibration amplitude, the patent dynamically adjusts the frequency while maintaining amplitude. The lowered frequency during countersinking reduces clatter marks on the surface while the sustained amplitude continues to suppress axial clattering, resolving the contradiction between surface smoothing and clatter prevention.
Solution Approach 2:
The patent changes the frequency parameter while maintaining amplitude, rather than decreasing amplitude. This approach achieves surface smoothing by lowering frequency to reduce clatter marks, while simultaneously preventing axial clattering through continued vibration at the lowered frequency.
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 effectively suppresses axial clattering, improves surface quality, and enhances the dimensional accuracy of the bore and counterbore, particularly in materials like plastics where fraying and splintering are reduced, and optimizes machining time.
Implementation Method 1
the axial feed movement of the drilling/countersinking tool is superimposed by an axial vibration so as to break the chips that arise in the drilling of the workpiece
Implementation Method 2
the frequency of the axial vibration is lowered to a final machining frequency, and the machining process is continued at the final machining frequency as the maximum frequency of the axial vibration
Data Source
AI summary
A method for machining a workpiece is provided, wherein drilling of the workpiece and subsequent countersinking of the bore, obtained by the drilling, in the workpiece are performed by means of a drilling/countersinking tool in a machining process, wherein the drilling/countersinking tool in the machining process while being axially rotated is subjected to an axial feed movement relative to the workpiece that reaches a counterbore terminal position, and wherein the axial feed movement is superimposed by an axial vibration, wherein, when reaching a predefined frequency lowering position of the axial feed movement by the drilling/countersinking tool, the frequency of the axial vibration is lowered to a final machining frequency, and the machining process is continued at the final machining frequency as the maximum frequency of the axial vibration until the counterbore terminal position is reached.