Cutting Insert Land Geometry for Chipping-Resistant Corners
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Solution Overview
Problem
Conventional cutting inserts are prone to chipping at corner cutting edges due to their pointed nature, and increasing the radius of curvature is not always feasible without altering other cutting edge lengths, which are often predetermined.
Innovation Solution
A cutting insert design with a land width increasing towards the corner cutting edge, where the rate of increase for the first major cutting edge is two to five times larger than for the second major cutting edge, and the cutting edges are inclined to reduce the load on corner cutting edges and enhance their resistance to chipping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the radius of curvature of corner cutting edges is increased to prevent chipping, then corner cutting edge strength is improved, but the lengths of other cutting edge portions must be shortened
Solution Approach 1:
The land width is made to increase locally toward the corner cutting edge, creating a gradient structure where the land is narrower at the major cutting edge and wider at the corner cutting edge. This local variation in land width strengthens the corner cutting edge without requiring to increase its radius of curvature, thereby maintaining the predetermined lengths of all cutting edge portions.
2Strength
If the land width increases toward the corner cutting edge, then corner cutting edge strength is improved, but chip discharge direction changes
Solution Approach 1:
The land width parameter is varied along the cutting edge, transitioning from a constant width to a gradient width that increases toward the corner cutting edge. This parameter change serves dual purposes: strengthening the corner cutting edge by increasing land width, and controlling chip discharge direction by the inclined configuration of the land.
Data Source
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AI summary
The present invention provides an insert, for use in rotary cutting, which has a corner cutting edge that is resistant to fracture. A cutting insert (1) has an upper surface (11), a lower surface (21), and a side surface (31) connecting the upper and lower surfaces, and an intersecting edge between the upper surface and the side surface is provided with a cutting edge (4). The cutting edge comprises a second major cutting edge (42), a first major cutting edge (43), a corner cutting edge (41) connected to these major cutting edges, and a flat cutting edge (44), in the order mentioned. An angle (θ) formed by the second major cutting edge and the first major cutting edge is an obtuse angle. An interior angle (α) formed by the flat cutting edge and the first major cutting edge is larger than an interior angle (β) formed by the flat cutting edge and the second major cutting edge. A land (12) is provided adjacent to the first major cutting edge on the upper surface and the width of the land (12) increases toward the first corner cutting edge.