Three-Nose Turning Insert for 90° Corner Chip Control
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Solution Overview
Problem
Existing turning inserts face challenges in effectively machining external 90° corners, particularly in radial turning, due to poor chip control and increased insert wear, especially when the entering angle is high.
Innovation Solution
A turning insert with three nose portions, featuring a first and second cutting edge with specific sub-portions and a convex nose cutting edge, along with rotation prevention means and chip breaker protrusions, allows for improved chip breaking and reduced insert wear across various feed directions, including axial and radial turning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If common turning inserts (TNMG or TCMT) are used for radial turning away from the rotational axis, then the machining operation can be performed, but chip control becomes poor and insert wear increases
Solution Approach 1:
The cutting insert is divided into three separate nose portions (first, second, and third nose portions) instead of a single nose portion. Each nose portion has specific cutting edges designed for different machining operations. This segmentation allows optimal chip control and reduced wear by selecting the appropriate nose portion for the specific operation (radial turning, axial turning, or out-facing).
Solution Approach 2:
Different nose portions have different geometric characteristics tailored to specific machining operations. The first nose portion is optimized for radial turning with specific cutting edge angles, the second for axial turning, and the third for out-facing operations. This local optimization of geometry at different locations on the insert improves chip control and reduces wear for each specific operation.
2Adaptability or versatility
If a single nose portion design is used, then the insert structure is simple, but versatility in handling different feed directions (axial, radial, out-facing) is limited
Solution Approach 1:
The cutting insert is designed with three nose portions, each capable of performing different machining operations (radial turning, axial turning, out-facing). This multi-functionality allows a single insert to handle various feed directions and machining operations, replacing what would traditionally require multiple different inserts, thereby improving versatility while maintaining reasonable structural complexity.
3Ease of manufacture
If conventional cutting edges are used, then the insert is easy to manufacture, but chip breaking performance is insufficient, especially at entering angles between 10° and 45°
Solution Approach 1:
The cutting edges are designed with specific geometric parameters including particular nose angles, rake angles, and edge radii optimized for different operations. The first nose portion has specific angle parameters for radial turning, the second for axial turning, and the third for out-facing. These parameter optimizations improve chip breaking performance across different entering angles (10°-45°) while maintaining manufacturability through standardized geometric features.
Data Source
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Figure 6
AI summary
A turning insert (1) comprising a top surface (8), an opposite bottom surface (9), side surfaces (13) connecting the top surface (8) and the bottom surface (9), a reference plane (RP) located parallel to and between the top surface (8) and the bottom surface (9), a center axis (A1) extending perpendicular to the reference plane (RP) and intersecting the reference plane (RP), three nose portions (15, 15', 15") formed symmetrically around the center axis (A1), each nose portion (15, 15', 15") comprising a first cutting edge (11, 11', 11"), a second cutting edge (12, 12', 12") and a convex nose cutting edge (10, 10', 10") connecting the first (11, 11', 11") and second (12, 12', 12") cutting edges, wherein in a top view the first (11) and second (12) cutting edges on the same nose portion (15) forms a nose angle (α) of 25-50° relative to each other, the first cutting edge (11) comprises a first sub-portion (111) and a second sub-portion (112), wherein a distance from the nose cutting edge (10) to the first sub-portion (111) is shorter than a distance from the nose cutting edge (10) to the second sub-portion (112), wherein a distance from the first sub-portion (111) to the reference plane (RP) decreases at increasing distance from the nose cutting edge (10), wherein a distance from the second sub-portion (112) to the reference plane (RP) increases at increasing distance from the nose cutting edge (10), and wherein the bottom surface (9) comprises rotation prevention means (40, 40', 40", 41, 42, 43, 44).