Machine Tool Oscillation Control for Smooth Arbitrary Stop Timing
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Solution Overview
Problem
Existing oscillation cutting techniques fail to smoothly stop oscillation at an arbitrary timing, leading to shock on the machine tool and degradation of machining tool life and workpiece accuracy.
Innovation Solution
A machine tool control device with an oscillation command generator that gradually attenuates oscillation amplitude and adjusts oscillation phase to smoothly stop oscillation at an arbitrary timing, reducing shock by superimposing an oscillation command on a movement command.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If oscillation is stopped rapidly by changing movement command, then oscillation stops quickly, but shock is caused on the machine tool
Solution Approach 1:
The control device determines an oscillation stop timing in advance before the actual stop is needed, and gradually attenuates the oscillation amplitude from that predetermined timing. This preliminary action allows the oscillation to be reduced smoothly over time rather than stopping abruptly, thereby preventing shock on the machine tool while achieving timely oscillation cessation.
2Manufacturing precision
If oscillation amplitude is decreased according to remaining movement distance, then oscillation stops at predetermined position, but cannot smoothly stop at arbitrary timing
Solution Approach 1:
The control device dynamically adjusts the oscillation amplitude based on real-time conditions rather than following a fixed schedule tied to remaining movement distance. By determining oscillation stop timing adaptively and gradually attenuating amplitude from that point, the system can smoothly stop oscillation at arbitrary timings while maintaining position accuracy, thus achieving both precision and versatility.
3Productivity
If oscillation stops abruptly, then machining process resumes quickly, but chip shredding properties are degraded
Solution Approach 1:
The control device determines oscillation stop timing in advance and gradually attenuates the oscillation amplitude over a period rather than stopping immediately. This preliminary, gradual reduction maintains chip shredding properties by avoiding abrupt changes in cutting conditions, while still enabling timely resumption of the machining process once oscillation is sufficiently reduced.
Data Source
AI summary
The purpose of the present invention is to provide a device for controlling a machine tool with which it is possible to smoothly stop oscillation at an arbitrary timing without loss of cutting-chip-shredding performance, and to minimize shock produced in the machine tool. The present invention provides a device 1 for controlling a machine tool for performing machining while causing a tool and a workpiece to oscillate relative to each other, the device 1 for controlling a machine tool comprising: an oscillation command generation unit 12 for generating an oscillation command on the basis of a machining condition and an oscillation condition; an oscillation stoppage assessment unit 13 for assessing the timing of oscillation stoppage; and a position speed control unit 17 for causing, on the basis of a superimposition command generated by superimposing the oscillation command onto a position command or a position deviation, the tool and the workpiece to oscillate relative to each other. The oscillation command generation unit 12 causes the oscillation amplitude to gradually attenuate from the timing at which oscillation stoppage is communicated from the oscillation stoppage assessment unit 13.