Thread-Cutting CNC Control With Multi-Axis Vibration Phasing
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Solution Overview
Problem
Existing numerical controllers for machine tools performing thread cutting with chip shredding face challenges in maintaining machining accuracy due to core misalignment caused by relative vibration between the cutting tool and the workpiece, particularly when the cutting tool is vibrated only along one axis.
Innovation Solution
A numerical controller that applies vibration to two or more axes (X, Y, Z) during thread cutting, allowing the cutting tool and workpiece to vibrate relative to each other along the thread groove, and adjusts the vibration phase relative to the spindle phase for each cutting process to minimize misalignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If vibration is applied to only one axis in radial directions of the workpiece, then the cutting tool can vibrate relative to the workpiece, but core misalignment occurs on the workpiece being rotated, deteriorating machining accuracy
Solution Approach 1:
The patent transitions from single-axis vibration to multi-axis vibration by applying vibration not only in radial directions but also in axial directions of the workpiece. This dimensional expansion disperses the vibration forces across multiple axes, preventing core misalignment while maintaining effective chip breaking and surface finish quality.
Solution Approach 2:
The patent combines vibration across multiple axes (X, Y, and Z directions) to create a composite vibration effect. This multi-directional vibration approach integrates the benefits of radial vibration for chip breaking with axial vibration for preventing core misalignment, achieving superior machining accuracy without the drawbacks of single-axis vibration.
2Manufacturing precision
If the cutting tool vibrates relative to the workpiece in radial directions only, then chip breaking is achieved, but the tip of the cutting tool is influenced by vibration, deteriorating machining accuracy
Solution Approach 1:
The patent introduces axial vibration components in addition to radial vibration, changing the vibration from a single-dimensional radial motion to a multi-dimensional motion pattern. This dimensional change redistributes the vibration effects, reducing the concentrated influence on the cutting tool tip while maintaining effective chip breaking through radial vibration components.
Solution Approach 2:
The patent segments the vibration into distinct radial and axial components applied simultaneously. By separating the vibration into orthogonal directions, the radial component handles chip breaking while the axial component mitigates the harmful effects on the cutting tool tip, achieving a division of functional responsibilities that improves overall machining accuracy.
3Manufacturing precision
If vibration phase is not adjusted between cutting-in processes, then the machining process is simple, but core misalignment occurs due to cumulative vibration effects, deteriorating machining accuracy
Solution Approach 1:
The patent implements periodic adjustment of vibration phase between successive cutting-in processes. By systematically varying the phase angle in a periodic manner across different passes, the cumulative vibration effects are randomized and prevented from causing consistent core misalignment, thereby improving machining accuracy through a relatively simple phase modulation approach.
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 core misalignment and improves the accuracy of the finished shape by dispersing forces applied to the workpiece, reducing the influence on the cutting tool tip.
Implementation Method 1
a vibration superimposing unit that superimposes vibration to be applied to two axes or more among the three axes on the relative movement between the cutting tool and the machining target so that the cutting tool and the machining target vibrate relative to each other along a thread groove
Data Source
AI summary
It is possible to suppress core misalignment from occurring due to relative vibration between a cutting tool and a workpiece, to improve accuracy of a finished shape, and to suppress a tip of the cutting tool from being influenced. A numerical controller that causes a machine tool to perform an operation for performing thread cutting through which a cutting tool and a machining target are allowed to move relative to each other to perform cutting-in processes a plurality of times on the machining target to form a thread on the machining target, including: a driver that controls a spindle that rotates the machining target, and drive axes having three axes; a vibration superimposing unit that superimposes vibration to be applied to two axes or more among the three axes on the relative movement between the cutting tool and the machining target so that the cutting tool and the machining target vibrate relative to each other along a thread groove; and a thread cutting vibration adjusting unit that shifts, by a vibration phase shift amount set beforehand, a phase of the vibration relative to a phase of the spindle per each of the cutting-in processes to be performed the plurality of times.