Asymmetric Turning Insert Geometry for Chip Control and Tool Life
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Solution Overview
Problem
Existing turning inserts face challenges with long or undesirable chip shapes during metal cutting, particularly with low carbon steels at low depth of cut, leading to increased cutting forces and reduced tool life, and current solutions either shorten tool life, compromise surface finish, or require expensive coolant systems.
Innovation Solution
The turning insert features a second cutting edge positioned to the right of the nose cutting edge, with a convex third wall and angled rake surfaces to reduce radial cutting forces, and includes a nose cutting edge that slopes between 10 to 30 degrees and a wiper edge for improved chip formation and force balance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If a smaller nose radius is chosen to reduce chip length, then chip shape is improved, but the life of the turning insert decreases
Solution Approach 1:
The turning insert employs an asymmetric geometry where the second cutting edge is positioned at a right-hand side of the nose cutting edge, creating an unequal distribution of cutting forces. This asymmetric design allows the insert to handle long chips effectively while maintaining edge integrity and extending insert life, resolving the contradiction between chip shape control and insert durability.
Solution Approach 2:
The invention introduces a vertical dimension to the cutting edge arrangement by positioning the second cutting edge at a different height relative to the nose cutting edge. This three-dimensional configuration enables better chip containment and force distribution without compromising insert life, addressing the limitation of traditional two-dimensional nose radius adjustments.
2Shape
If a higher feed is chosen to reduce chip length, then chip shape is improved, but the machined surface finish is reduced
Solution Approach 1:
The asymmetric positioning of the second cutting edge relative to the nose cutting edge creates a balanced force distribution that allows higher feed rates without compromising surface finish. The unequal arrangement of cutting edges compensates for the increased feed by distributing mechanical loads differently, maintaining both chip control and surface quality.
3Shape
If high pressure coolant is used to break chips, then chip shape is improved, but expensive investments are required
Solution Approach 1:
The turning insert is designed to break chips through its own geometric configuration rather than relying on external coolant systems. The asymmetric cutting edge arrangement and convex third wall create natural chip containment and breaking mechanisms that function without high-pressure coolant, eliminating the need for expensive coolant infrastructure while achieving desirable chip shapes.
Solution Approach 2:
The invention extracts the chip breaking function from the coolant system and integrates it directly into the insert geometry. By incorporating chip breaking capabilities into the insert's structural design through asymmetric edges and convex walls, the system eliminates dependence on external high-pressure coolant systems, reducing overall system complexity and cost.
4Force
If the second cutting edge is positioned to reduce radial cutting forces, then cutting forces are reduced, but chip formation may be affected
Solution Approach 1:
The asymmetric positioning of the second cutting edge at a right-hand side of the nose cutting edge creates a specific force distribution pattern that reduces radial cutting forces while simultaneously promoting favorable chip formation. The unequal arrangement ensures that chip flow is directed along paths that maintain both low radial forces and proper chip shape.
Solution Approach 2:
The convex third wall introduces a curved geometric element that guides chip flow in a controlled manner. This curvature works in conjunction with the asymmetric cutting edge positioning to reduce radial forces while maintaining effective chip formation, as the curved surface naturally directs chips away from the cutting zone in a controlled pattern.
Data Source
Figure 1A~1B
Figure 1C~1K
Figure 1D~1H
AI summary
The application concenrs a turning insert (1) for longitudinal turning of metal work pieces, wherein a nose cutting edge (5;5') slopes from a trailing cutting edge (6;6') in direction towards a leading cutting edge (7;7'). A turning tool comprising a turning insert (1) is also disclosed.