Indexable Milling Insert Geometry for Chip Control and Low Noise
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Solution Overview
Problem
Existing cutting inserts for milling tools face challenges with toughness behavior, chip formation, control, and noise levels due to moderate effective angles of inclination, which affect cutting characteristics and tool performance.
Innovation Solution
A cutting insert with a strongly positive angle of inclination achieved by setting the axial tipping-in angle to neutral or negative and the radial tipping-in angle to extremely negative, combined with an acute entering angle, allowing for improved toughness and reduced noise levels, while maintaining a large number of cutting edges for extended tool life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If cutting inserts are made with conventional negative geometry and moderate angles of inclination, then the number of cutting edges can be increased, but the toughness behavior of cutting edges deteriorates and noise levels increase
Solution Approach 1:
The patent applies parameter changes by modifying the geometry parameters of the cutting insert, specifically implementing strongly positive angles of inclination (greater than 10 degrees) and acute entering angles (less than 45 degrees). These parameter changes transform the conventional negative geometry into a configuration that achieves both increased service life through multiple cutting edges and improved toughness behavior with reduced noise levels.
Solution Approach 2:
The patent employs asymmetry in the design of the cutting insert geometry, where the main cutting edge is configured with asymmetric angles relative to the insert body. The strongly positive angle of inclination and acute entering angle create an asymmetric configuration that optimizes both the number of usable cutting edges and the cutting performance characteristics including toughness and noise reduction.
2Object-affected harmful factors
If the angle of inclination is increased to improve toughness behavior, then noise levels decrease, but the number of cutting edges per insert is reduced
Solution Approach 1:
The patent resolves this contradiction through precise parameter changes, setting the angle of inclination within the range of greater than 10 degrees (strongly positive) and the entering angle within the range of less than 45 degrees (acute). These specific parameter values enable the insert to maintain seven or more cutting edges per side while simultaneously achieving reduced noise levels and improved toughness behavior.
Solution Approach 2:
The patent applies partial action by implementing strongly positive angles of inclination (exceeding conventional values) while maintaining the ability to form multiple cutting edges. The excessive positive angle would normally reduce the number of edges, but the acute entering angle compensates to maintain edge count while achieving the noise reduction and toughness benefits of the exaggerated angle.
3Ease of manufacture
If conventional negative geometry with right-angled clearance surfaces is used, then manufacturing is simplified, but chip formation and control characteristics are compromised
Solution Approach 1:
The patent applies parameter changes by modifying the clearance surface geometry from conventional right angles to strongly positive angles of inclination. The main clearance surface is configured at an angle greater than 10 degrees relative to the upper extension plane, and the secondary clearance surface is configured at an angle greater than 5 degrees. These parameter changes improve chip formation and control characteristics while remaining manufacturable.
Data Source
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Figure 5~6
AI summary
An indexable cutting insert (1) for a milling tool comprising an upper side (2) defining an upper extension plane and a lower side (3) defining a lower extension plane parallel to the upper extension plane. A centre axis (C2) extends perpendicularly through the upper and lower extension planes. A side surface (4) connects the upper side and the lower side, the side surface comprising a plurality of upper main clearance surfaces (5) and secondary clearance surfaces (6a, 6b). At least six identical and alternately usable upper cutting edges (7) extend around the upper side. Each cutting edge comprises a chip removing main cutting edge portion and at least one secondary cutting edge portion, the main cutting edge portion being formed in a transition between the upper side and one of said upper main clearance surfaces, the secondary cutting edge portion being formed in a transition between the upper side and one of said secondary clearance surfaces between two main cutting edge portions. The upper main clearance surfaces are formed at an obtuse inner angle α with respect to the upper extension plane as seen in side elevation view.