Curved Secondary Cutting Insert Edges for Stable High-Feed Milling
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Solution Overview
Problem
Existing indexable cutting inserts for high feed rate milling operations lack economic efficiency and robustness, with limited service life and instability in rotary cutting tools.
Innovation Solution
The design features continuously curved secondary cutting edges and a robust construction for the indexable cutting insert, which increases side cutting edge strength and prolongs service life, and a stable mounting system in the rotary cutting tool for secure operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If straight secondary cutting edges are used, then manufacturing is simpler, but cutting edge strength is reduced
Solution Approach 1:
The patent applies curvature to the secondary cutting edges, transforming them from straight lines to arcs with specific radii. This curvature increases the cutting edge strength by distributing mechanical stresses more effectively along the edge, while still allowing for practical manufacturing through standard cutting and grinding processes. The curved geometry provides structural reinforcement without excessive manufacturing complexity.
2Strength
If curved secondary cutting edges are used, then cutting edge strength increases, but manufacturing complexity increases
Solution Approach 1:
The patent specifies precise geometric parameters for the curved secondary cutting edges, including radius ranges (e.g., R5 to R15 for corner cutting edges, R2 to R10 for secondary cutting edges) and angle ranges (e.g., 45° to 60° for corner angles). By controlling these parameters within defined ranges, the design achieves optimal strength while managing manufacturing complexity through standardized dimensional specifications rather than arbitrary complex curves.
3Duration of action of stationary object
If straight corner cutting edges are used, then manufacturing is easier, but service life is limited
Solution Approach 1:
The corner cutting edges are designed as curved arcs rather than straight lines, with specified radius ranges (R5 to R15) and angle ranges (45° to 60°). This curvature reinforces the corner regions which are typically stress concentration points, thereby extending insert service life. The curved geometry distributes cutting forces more evenly across the corner area, reducing wear and chip buildup while remaining manufacturable through standard processes.
4Productivity
If simple square shape is used, then manufacturing is simpler, but cutting performance in high feed rate milling is insufficient
Solution Approach 1:
The patent maintains the overall square shape of the cutting insert for simplicity and compatibility with standard tool holders, but introduces localized geometric variations at critical areas. The secondary cutting edges are curved with specific radii, and corner regions have modified geometries with specified angles and arc radii. This local quality enhancement improves cutting performance in high feed rate milling by optimizing chip flow and edge strength where needed, while keeping the bulk geometry simple for easy manufacturing and tool holder compatibility.
Data Source
Figure 1~2
Figure 3a~3b
Figure 4~5
AI summary
An indexable cutting insert (20) has upper and lower surfaces (22, 24) with a peripheral surface (26) extending therebetween and having four side surfaces (30) alternating with four corner surfaces (32). The side and corner surfaces (30, 32) intersect the upper surface (22) to form side and corner cutting edges (40, 42) respectively. Each side cutting edge (40) includes a primary cutting edge (46) adjoining one of the corner cutting edges (42) at a first endpoint (N1) and a secondary cutting edge (48) adjoining another one of the corner cutting edges (42) at a second endpoint (N2). In a top view, the four primary cutting edges (46) define an imaginary first square (S1), each primary cutting edge (46) is tangential to its adjoining corner cutting edge (42), and each secondary cutting edge (48) is curved and entirely located in one of four imaginary quadrants (Q1, Q2, Q3, Q4). The insert is removably secured in a rotary cutting tool (58) such that one of the secondary cutting edges (48', fig. 9) contains the axially forwardmost point (NA) of the insert's upper peripheral edge (28).