Double-Sided Indexable Cutting Insert with Acute Angles
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Solution Overview
Problem
Existing cutting inserts in milling tools face limitations in cutting properties, particularly regarding chip shape geometry, targeted chip shaping, and recutting behavior during oblique or circular plunging, due to their design.
Innovation Solution
A double-sided indexable cutting insert with six cutting areas, featuring straight and arcuate cutting edges, acute angles between cutting edges, and a mirror-symmetrical design with vertices positioned below contact planes, enhancing chip breaking and steering, and improved immersion properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional cutting insert designs are used, then manufacturing simplicity is maintained, but chip shape geometry control and recutting behavior are insufficient
Solution Approach 1:
The cutting insert is divided into multiple cutting areas (first, second, and third cutting areas) with distinct cutting edge configurations. Each cutting area has specific straight and arcuate cutting edges designed for particular chip control functions, allowing precise manipulation of chip shape geometry while maintaining overall design coherence
Solution Approach 2:
Arcuate cutting edges are introduced in the third cutting area with specific radii of curvature. These curved edges work in conjunction with the straight cutting edges to create controlled chip breaking patterns and improve chip shape geometry, particularly for recutting operations
2Reliability
If cutting edges are designed with right angles, then manufacturing is simplified, but immersion properties and recutting behavior during oblique plunging are poor
Solution Approach 1:
The angle between adjacent straight cutting edges is changed from the conventional 90 degrees to an acute angle between 84° and 86°. This parameter modification significantly improves immersion properties and recutting behavior during oblique plunging operations while remaining feasible within standard manufacturing tolerances
3Manufacturing precision
If vertices of arcuate edges are positioned above contact planes, then structural stability is maintained, but chip breaking and chip steering capabilities are reduced
Solution Approach 1:
The vertices of the arcuate cutting edges are positioned below the contact planes, utilizing the vertical dimension between the cutting surface and the contact surface. This spatial arrangement creates additional chip breaking and shaping zones without compromising the stability of the insert in its seated position, as the contact planes remain intact for proper seating
4Productivity
If double-sided design with six cutting areas is implemented, then productivity is increased, but design complexity and manufacturing precision requirements increase
Solution Approach 1:
While the overall insert is symmetric to provide six cutting areas, the cutting edges within each area feature asymmetric angle configurations (84°-86° acute angles) optimized for specific cutting directions. This controlled asymmetry within a symmetric framework maximizes productivity while managing manufacturing precision requirements
Data Source
Figure 1
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Figure 4~5B
AI summary
The invention relates to a cutting insert (12) for a milling tool (10), comprising a first side (16), a second side (18) that is identical to the first side (16) and a circumferential surface (26) that extends between the first and the second side (16, 18), comprising a borehole (24) that extends along a borehole axis (22), wherein the cutting insert (12) is 120°-rotationally symmetrical to the borehole axis (22), wherein the cutting insert (12) has three respective identically formed cutting regions (28, 28', 28") both on the first side (16) and on the second side (18), which are positioned at the transition between the first side (16) and the circumferential surface (26) or at the transition between the second side (18) and the circumferential surface (26), wherein all six cutting regions (28, 28', 28'') each have a first straight cutting edge (30), a second straight cutting edge (32) and a third curved cutting edge (34), wherein a first end (38) of the first cutting edge (30) is connected to a first end (36) of the third cutting edge (34), and a first end (42) of the second cutting edge (32) is connected to a second end (40) of the third cutting edge (34), wherein the first and second cutting edges (30, 32) are equal in length, wherein the cutting insert (12) has a first contact surface (54) on the first side (16) running orthogonal to the borehole axis (22) and positioned in a first contact plane (56), and the cutting insert has a second contact surface (60) on the second side (18) running orthogonal to the borehole axis (22) and positioned in a second contact plane (62), and wherein the first cutting edges (30) are connected, by the second ends (48) thereof opposing the first ends (38), to a respective one of all six curved edges (44), the turning point (64) of which is positioned between the first and the second contact planes (56, 62).