Machine Tool Control for Asymmetric Reciprocal Cutting Motion
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Solution Overview
Problem
When the reciprocal vibration in a machine tool overlaps cutting work positions of forward and backward movements, leading to air cuts and degradation of machining efficiency, especially when the number of reciprocal vibrations per spindle rotation is less than one.
Innovation Solution
The machine tool is designed to perform one repetitive movement with respect to multiple relative rotations between the workpiece and the cutting tool, with the first speed set faster than the second speed, and the rotation angle during the backward movement is smaller than during the forward movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the number of reciprocal vibrations per spindle rotation is less than one, then chip separation is improved, but machining efficiency deteriorates due to extended air cut duration
Solution Approach 1:
The patent applies asymmetry by making the forward movement speed different from the backward movement speed in the reciprocal vibration. Specifically, the forward movement (cutting direction) and backward movement (return direction) are configured with unequal speeds, creating an asymmetric vibration pattern that optimizes both chip separation and machining efficiency by reducing air cut duration while maintaining effective cutting engagement
Solution Approach 2:
The patent implements dynamics by varying the speeds during forward and backward movements rather than maintaining a constant symmetric vibration pattern. The cutting tool's reciprocal vibration is made dynamic with adjustable speed parameters, allowing optimization of the cutting phase speed to improve material removal rate while controlling the return phase speed to minimize non-productive air cut time
2Manufacturing precision
If the cutting tool performs air cut during backward movement, then chip separation is achieved, but time is lost due to non-cutting motion
Solution Approach 1:
The patent utilizes periodic action through the reciprocal vibration mechanism, where the cutting tool alternates between forward cutting movement and backward return movement in a controlled periodic cycle. This periodic reciprocation creates regular chip separation while the duration and speed parameters of each phase can be optimized to minimize the time lost during non-cutting backward motion
Solution Approach 2:
The patent applies parameter changes by adjusting the speed parameters of the reciprocal vibration differently for forward and backward movements. By changing the speed parameters dynamically during different phases of the vibration cycle, the system optimizes the balance between achieving effective chip separation and minimizing the time spent in non-productive air cut positions
Data Source
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AI summary
To provide a machine tool that is capable of limiting degradation of machining efficiency when a cutting tool machines a workpiece by performing one repetitive movement with respect to multiple relative rotations between the workpiece and the cutting tool, and a control apparatus of the machine tool. In the machine tool (100) and the control apparatus (C) thereof, the repetitive movement means is configured so that the cutting tool (130) performs one repetitive movement with respect to multiple relative rotations between the workpiece (W) and the cutting tool (130) and so that a rotation angle of the relative rotation between the workpiece (W) and the cutting tool (130) during relative movement at the second speed is smaller than a rotation angle of the relative rotation during relative movement at the first speed in one repetitive movement, thereby limiting degradation of machining efficiency when the cutting tool (130) machines the workpiece (W) by performing one repetitive movement with respect to multiple relative rotations between the workpiece (W) and the cutting tool (130).