Nicked Cutting Edge Geometry to Reduce Machining Vibration
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Solution Overview
Problem
Cutting tools with uniformly aligned cutting edge portions and nicks experience high impulsive vibrations and increased cutting resistance, leading to reduced tool life during the machining of difficult-to-cut materials like nickel-base alloys.
Innovation Solution
The cutting tool design features cutting edge portions with varying inclination angles, where the angle of one cutting edge portion relative to the central axis is greater than the angle of the connecting line between its ends, reducing cutting resistance and preventing intermittent contact with the workpiece, thereby minimizing vibrations and extending tool life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If cutting edge portions are uniformly aligned and alternately disposed with nicks, then swarf is split to reduce cutting resistance, but impulsive vibrations such as chattering vibrations occur due to intermittent contact
Solution Approach 1:
The cutting edge portions are designed with different inclination angles relative to the central axis, creating an asymmetric configuration. Specifically, the first cutting edge portion has a different inclination angle than the second cutting edge portion, which prevents simultaneous intermittent contact and reduces impulsive vibrations while maintaining the swarf-splitting function for reduced cutting resistance
Solution Approach 2:
The cutting edge portions are arranged to contact the workpiece in a periodic sequence rather than simultaneously. By controlling the inclination angles and positions, the cutting edges engage the workpiece in alternating fashion, which reduces the impulsive vibrations caused by simultaneous intermittent contact while maintaining continuous cutting action
2Temperature
If cutting edge portions are made discontinuous with nicks, then temperature rise of the cutting edge is reduced, but impulsive vibrations increase due to intermittent contact
Solution Approach 1:
The asymmetric inclination angles of different cutting edge portions ensure that they do not contact the workpiece simultaneously during intermittent engagement. This asymmetry distributes the thermal and mechanical loads more evenly over time, reducing both temperature rise and impulsive vibrations that would otherwise occur with uniform alignment
Solution Approach 2:
The cutting edge is segmented into multiple cutting edge portions separated by nicks, which divides the continuous cutting action into discrete segments. This segmentation allows for heat dissipation between contact events while the asymmetric arrangement ensures these segments engage in a staggered sequence, reducing impulsive vibrations
Data Source
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AI summary
A cutting tool includes a shaft portion and a plurality of edge region groups. The shaft portion extends along the central axis and includes an outer peripheral surface surrounding the central axis. The plurality of edge region groups are spirally provided on the outer peripheral surface. The plurality of edge region groups include a first edge region group divided by a first nick. The first edge region group includes a first edge region and a second edge region that is adjacent to the first edge region, with the first nick lying therebetween. The first edge region includes a first rake face portion and a first flank face portion. The ridgeline between the first rake face portion and the first flank face portion constitutes a first cutting edge portion. The second edge region includes a second rake face portion and a second flank face portion. The ridgeline between the second rake face portion and the second flank face portion constitutes a second cutting edge portion. As seen from the direction perpendicular to a plane tangent to the outer peripheral surface, in a state where the central axis overlaps a first end on the front end side of the first cutting edge portion, the inclination angle of the first cutting edge portion relative to the central axis is larger than the inclination angle of a straight line relative to the central axis, the straight line connecting the first end to a second end on the front end side of the second cutting edge portion.