Cutting Insert Rake-Face Geometry for Stable Chip Flow at Low Feed
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Solution Overview
Problem
Existing cutting inserts experience unstable chip discharge direction and generation under conditions of small depth of cut and low feed rate, leading to potential chip contact with a small tip portion of protruding sections, which can destabilize chip movement.
Innovation Solution
The cutting insert features a rhombic-shaped top surface with a cutting edge formed along the entire periphery, parallel to a reference plane, and includes raised parts with specific geometries such as the second raised part with a convex curved shape and a third raised part with a tapered shape, which stabilize chip movement and direction by providing a wider contact area and controlled curvature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the feed rate is decreased to improve surface finish, then the chip thickness decreases, but the chip discharge direction becomes unstable
Solution Approach 1:
The patent introduces a protruding section as an intermediary element between the corner cutting edge and the chip flow path. This protruding section acts as a mediator that guides and stabilizes the chip discharge direction, ensuring stable chip control even when chip thickness is reduced by decreasing the feed rate for better surface finish.
2Manufacturing precision
If the depth of cut is decreased to improve precision, then the chip thickness decreases, but the likelihood of chip contact with the protruding section tip increases
Solution Approach 1:
The patent applies local quality by designing the protruding section with non-uniform width - the width in the direction orthogonal to the bisecting line varies along the length of the protruding section. This creates different local characteristics: a smaller tip portion for precision guidance and a wider base portion for stable chip support, allowing the structure to adapt to different cutting conditions and maintain chip stability even at small depths of cut.
Data Source
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AI summary
A cutting insert (1) of one embodiment is provided with: an insert body having a top surface (2) that has a corner section (21), a first side (22) and a second side (23), a bottom surface (3), and side surfaces (4); a cutting edge (6) that is positioned at an intersection between the top surface and the side surfaces, and includes a corner cutting edge (61), a first cutting edge (62) and a second cutting edge (63); a rake face (5) that slopes downward away from the cutting edge; and a first raised part (71) that is positioned inside the rake face, and rises upward. The first raised part includes a protruding section (71 c) that is positioned on a bisecting line of the corner section and protrudes toward the corner cutting edge. The cutting insert is further provided with a second raised part (72) that is positioned on the tip side of the protruding section and extends toward the first cutting edge and the second cutting edge from the protruding section, and has a convex curved shape in which, when viewed from above, the outer peripheral edge on the corner section side forms a protuberance extending toward the corner section.