Turning Insert Geometry for Stable Cutting at Small Entering Angles
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Solution Overview
Problem
Existing cutting inserts for turning operations are not versatile and strong enough, particularly when using small entering angles, and are prone to damage during varying cutting depths or specific cutting directions.
Innovation Solution
A cutting insert design with alternating major and minor corner edges, where the major edges are less sharp and longer, allowing for robust cutting and smooth chip formation, and enabling use in both longitudinal and facing operations with varying cutting depths, and secure mounting in a turning tool.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a small entering angle is used for longitudinal external turning, then chip width increases and chip thickness decreases, reducing tool wear, but the cutting insert strength becomes insufficient for some applications
Solution Approach 1:
The cutting insert employs asymmetric corner edge design where major corner edges have a larger radius of curvature (less sharp) compared to minor corner edges. This asymmetry allows the insert to maintain strength at critical corners while enabling small entering angle operations. The different corner edge geometries provide tailored performance for different cutting scenarios.
Solution Approach 2:
Different regions of the cutting insert have different geometric properties: major corner edges have larger radii for strength and stability, while minor corner edges have smaller radii for sharper cutting action. This local differentiation of geometric quality allows the single insert to handle multiple cutting conditions effectively.
2Reliability
If cutting inserts are designed for specific applications and cutting directions, then they perform well in those specific situations, but they lack versatility for other applications
Solution Approach 1:
The cutting insert is designed with six corner edges (three major and three minor) arranged alternately around the perimeter, allowing it to perform multiple cutting functions. The same insert can be used for longitudinal external turning, longitudinal internal turning, and facing operations by selecting appropriate corner edges, making it a universal tool for various turning operations.
Solution Approach 2:
The cutting insert perimeter is segmented into six distinct corner edges with different geometric properties (three major with larger radii, three minor with smaller radii). This segmentation allows selective use of different edges for different cutting scenarios, providing versatility while maintaining specialized performance characteristics.
3Manufacturing precision
If sharp corner edges are used for precise cutting, then cutting precision improves, but the corner edges become more susceptible to damage during varying cutting depths
Solution Approach 1:
The cutting insert employs asymmetric corner edge design where major corner edges have a larger radius of curvature (less sharp) compared to minor corner edges. This asymmetry allows the insert to maintain strength at critical corners while enabling small entering angle operations. The different corner edge geometries provide tailored performance for different cutting scenarios.
Solution Approach 2:
The major corner edges with larger radii of curvature act as a cushion or buffer against sudden cutting depth variations and shocks. This pre-designed geometric cushioning protects the cutting insert from damage that would otherwise occur with sharp corners during unstable cutting conditions.
4Strength
If alternating major and minor corner edges are used, then the cutting insert becomes more robust for varying cutting depths, but the insert geometry becomes more complex
Solution Approach 1:
The cutting insert perimeter is segmented into six distinct corner edges with different geometric properties (three major with larger radii, three minor with smaller radii). This segmentation allows selective use of different edges for different cutting scenarios, providing versatility while maintaining specialized performance characteristics.
Solution Approach 2:
The cutting insert merges multiple functions and geometric characteristics into a single component. By integrating both major (less sharp, stronger) and minor (sharper, more precise) corner edges on one insert, it combines the benefits of different geometries without requiring multiple separate tools, thus managing complexity while providing robust performance.
Data Source
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AI summary
The invention relates to a cutting insert (1) for a turning tool, the cutting insert comprising: - a first surface (2) and a second surface (3), wherein the first and second surfaces are arranged opposite each other and facing opposite directions; - a peripheral surface (4) connecting the first surface (2) and the second surface (3), wherein an intersection between the first surface and the peripheral surface forms an edge that includes six side edges (5) connected via six corner edges (6) that are arranged pairwise opposite each other, wherein, of each of the pairs of opposite corner edges one corner edge is a minor corner edge (6a) and the other corner edge is a major corner edge (6b), wherein the corner edges (6) are arranged such that the minor corner edges (6a) and the major corner edges (6b) are alternately arranged along the edge. In a plan view of the first surface (2), each corner edge (6) is formed by one or more curvilinear segments, wherein each major corner edge (6b) has a first length of extension (L1) and each minor corner edge (6a) has a second length of extension (L2), and wherein any two adjacent side edges (5) that are connected via one of the major corner edges (6b) forms a first internal angle (α) with respect to each other, and any two adjacent side edges (5) that are connected via one of the minor corner edges (6a) forms a second internal angle (β) with respect to each other. The first length of extension (L1) is greater than the second length of extension (L2) and the second internal angle (β) is greater than the first internal angle (α).