Double-Sided Cutting Insert With Wiper Edge Fracture Resistance
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Solution Overview
Problem
Negative-type cutting inserts exhibit high cutting resistance, while positive-type inserts have low economic efficiency and are prone to fracture due to sharper cutting edges.
Innovation Solution
A cutting insert design with a hexagonal plate shape, where both end surfaces have cutting edges and wiper edges, with the wiper-edge side surface inclined, allowing for constant width and reduced cutting resistance, and extended tool life by using both surfaces equally.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a negative-type cutting insert is used, then the cutting insert structure is simple and easy to manufacture, but the cutting resistance is high
Solution Approach 1:
The patent inverts the conventional negative-type insert design by creating a positive-type insert where the peripheral side surface is gradually inclined inward. This inversion changes the cutting action from pushing material (negative type) to shearing material (positive type), thereby reducing cutting resistance while maintaining manufacturing feasibility through symmetric design
2Force
If a positive-type cutting insert is used, then the cutting resistance is reduced, but the economic efficiency is low because only one end surface is provided with cutting edges
Solution Approach 1:
The patent applies asymmetry in the sense that while each individual end surface has a positive-type configuration optimized for cutting, the overall insert is symmetric with both end surfaces equipped with identical cutting edge arrangements. This allows the insert to be used on both sides, effectively doubling its service life and improving economic efficiency
Solution Approach 2:
The patent extends the utility of the cutting insert from single-sided use to double-sided use by providing cutting edges on both end surfaces. This adds a dimensional aspect to the insert's functionality, allowing it to be rotated and used from either end, thereby improving productivity and economic efficiency
3Force
If a positive-type cutting insert with gradually inclined peripheral side surface is used, then the cutting resistance is reduced, but the cutting edges are sharper and prone to fracture
Solution Approach 1:
The patent applies local quality by providing different surface characteristics in different regions. The peripheral side surface has a gradual inclination for efficient cutting, while the end surfaces have optimized cutting edge geometries with appropriate radii to balance sharpness and strength. The wiper edges specifically have larger radii to prevent fracture while maintaining surface finish quality
4Manufacturing precision
If wiper edges are added to enhance surface roughness, then the surface finish is improved, but the cutting edges become more prone to fracture
Solution Approach 1:
The patent uses parameter changes by varying the radius of the cutting edges based on their function. Main cutting edges have smaller radii for effective cutting, while wiper edges have larger radii (e.g., 0.5-2.0mm) to reduce stress concentration and prevent fracture. This parameter optimization allows wiper edges to perform surface finishing without being overly prone to fracture
Data Source
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AI summary
A cutting insert which is less prone to fracture is provided in consideration of the arrangement of wiper edges. A cutting insert comprises two opposing first and second end surfaces (2, 3) whose contour shapes are each substantially polygonal and a peripheral side surface (4) connecting these end surfaces, wherein a corner cutting edge (6), a first cutting edge (7), a second cutting edge (8), which is on the side opposite to the first cutting edge with respect to the corner cutting edge, and a wiper edge (9) formed between the second cutting edge and the corner cutting edge, are formed at least in part of an intersecting edge between the first end surface and the peripheral side surface. In the peripheral side surface, when regarding a side surface part of the wiper edge as a wiper-edge side surface (14) and a direction perpendicular to the second cutting edge as a direction V as viewed from a direction facing the first end surface, in a side view from the direction V, the boundary of the wiper-edge side surface which is close to the second side surface is inclined with respect to a direction perpendicular to the first end surface, and the wiper-edge side surface has a constant width between the first and second end surfaces.