Feed-Axis Oscillation Control for Chip Breaking and Shock Reduction
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Solution Overview
Problem
Existing hole-cutting processes using drills face issues with chip entanglement and tool damage due to shock during cutting-in, as conventional methods fail to effectively break up and discharge chips while reducing shock.
Innovation Solution
A machine tool control device that oscillates the cutting tool relative to the feed direction, using a superimposed command generated by combining a sinusoidal oscillation command with a position command to control the feed axis, allowing for phase and amplitude adjustments based on predetermined conditions to minimize shock and enhance chip discharge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If step feeding and pecking are used to break up and discharge chips, then chip discharge is improved, but large shock occurs when the tool cuts into the workpiece, damaging the blade edge
Solution Approach 1:
The patent applies mechanical vibration by superimposing an oscillation command on the position command, causing the cutting tool to vibrate in the feed direction. This vibration breaks up chips during cutting while controlling the oscillation parameters (amplitude, phase, frequency) to minimize shock during cutting-in, thereby protecting the blade edge from damage.
Solution Approach 2:
The patent implements periodic action through oscillatory motion of the cutting tool in the feed direction. The tool periodically moves forward and backward during cutting, which continuously breaks up chips and discharges them from the cutting zone. The periodic oscillation is controlled to reduce impact shock during cutting-in while maintaining effective chip breaking throughout the process.
2Object-generated harmful factors
If a tool is vibrated at low frequency to break up chips, then chip breaking is improved, but shock reduction during cutting-in is not achieved
Solution Approach 1:
The patent applies dynamics by making the oscillation parameters (amplitude, phase, frequency) variable rather than fixed. The oscillation command generating unit dynamically adjusts these parameters based on the cutting state, allowing high oscillation amplitude for effective chip breaking during steady cutting, while reducing oscillation amplitude or adjusting phase to minimize shock during cutting-in. This dynamic control resolves the contradiction between chip breaking effectiveness and shock reduction.
Solution Approach 2:
The patent changes oscillation parameters (amplitude, phase, frequency) of the tool vibration based on the cutting stage. During cutting-in, parameters are adjusted to reduce shock, while during steady cutting, parameters are optimized for effective chip breaking. This parameter adaptation allows the system to achieve both shock reduction and effective chip breaking at different stages of the cutting process.
3Force
If feed rate is increased and decreased to reduce shock during cutting-in, then shock is reduced, but the tool does not move backward, making it difficult to discharge chips
Solution Approach 1:
The patent uses mechanical vibration in the feed direction to achieve both shock reduction and chip discharge. The oscillation command causes the tool to vibrate with sufficient amplitude to break up and discharge chips, while the controlled oscillation characteristics (frequency, phase, amplitude modulation) reduce shock during cutting-in. This eliminates the need for large backward movements while maintaining effective chip breaking.
Solution Approach 2:
The patent implements periodic oscillatory motion in the feed direction that combines forward cutting motion with backward vibration. This periodic action allows the tool to move backward during part of the oscillation cycle to discharge chips, while the overall forward progress maintains cutting efficiency. The periodic vibration reduces shock during cutting-in compared to conventional pecking operations.
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 device effectively breaks up and discharges chips, reducing tool damage and shock during cutting-in, thereby improving processing accuracy and tool life.
Implementation Method 1
a tool is vibrated at a low frequency with respect to a feed direction to cut into a workpiece
Implementation Method 2
generate an oscillation command causing the cutting tool to oscillate with respect to the feed direction relative to the workpiece, based on a predetermined oscillation condition
Implementation Method 3
control an electric motor configured to drive the feed axis, based on a superimposed command generated by superimposing the oscillation command generated by the oscillation command generating unit onto a position command or a position error
Data Source
AI summary
A machine tool control device which reliably divides and discharges chips, and which suppresses damage to a tool by reducing shock when the tool cuts into a workpiece. The machine tool control device causes the tool to rotate and executes a cutting process to move the tool and the workpiece while causing the same to oscillate relative to one another in a feed direction, and is provided with an oscillation command generating unit which generates an oscillation command on the basis of a predetermined oscillation condition. A position and speed control unit controls a motor by superimposing the oscillation command generated by the oscillation command generating unit onto a position command or a position deviation. The oscillation command generating unit changes an oscillation command phase progression method and/or an oscillation command amplitude on the basis of an oscillation phase calculated from on a predetermined oscillation condition, or based on time.