Turning Insert Geometry for Longer Tool Life and Chip Evacuation
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Solution Overview
Problem
The existing turning method in EP2572816B1 results in unsatisfactory tool life for the turning insert due to inadequate chip control and uneven wear distribution, leading to reduced efficiency and effectiveness in machining metal workpieces.
Innovation Solution
A method involving a turning insert with a nose angle of less than or equal to 85°, where the second cutting edge forms a back clearance angle of more than 90°, allowing the first cutting edge to be active ahead of the nose cutting edge, and the insert is positioned such that all parts are ahead of the nose cutting edge in the feed direction, with controlled movement to distribute wear evenly and improve chip evacuation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If a conventional turning insert with nose angle greater than 85° is used, then the insert can machine external 90° corners, but the tool life is unsatisfactory due to uneven wear distribution
Solution Approach 1:
The patent changes the geometric parameters of the turning insert, specifically reducing the nose angle to 85° or less and positioning the second cutting edge to form a back clearance angle of more than 90°. This parameter modification redistributes the wear pattern across the cutting edges, preventing concentrated wear at the nose and thereby extending tool life while maintaining machining capability.
2Adaptability or versatility
If the turning insert is reoriented between machining steps, then different surfaces can be machined, but the process time increases and efficiency decreases
Solution Approach 1:
The patent designs the turning insert with multiple cutting edges positioned at specific orientations, enabling the same insert to perform multiple machining operations (axial turning, facing, chamfering) without requiring reorientation. The second cutting edge is specifically positioned to form a back clearance angle greater than 90°, allowing it to function as an active cutting edge in subsequent operations, thereby eliminating tool reorientation and reducing process time.
3Ease of manufacture
If the chip evacuation path is not optimized, then the machining can be simpler, but chip jamming occurs and surface finish deteriorates
Solution Approach 1:
The patent optimizes the local geometry of the cutting edges and their positioning relative to the workpiece surface. The second cutting edge is positioned to create specific chip flow patterns that facilitate chip evacuation. This localized geometric optimization ensures chips are directed away from the cutting zone and machined surface, preventing chip jamming and maintaining surface finish quality without complicating the overall machining process.
Data Source
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Figure 2
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AI summary
A method to form a surface (53) on a metal work piece (50) comprising a first machining step of providing a turning insert (1) comprising a first cutting edge (11), a second cutting edge (12) and a convex nose cutting edge (10) connecting the first (11) and second (12) cutting edges, selecting a nose angle (α) formed between the first (11) and second (12) cutting edges to be less than or equal to 85°, The method comprises the further steps of adapting the second cutting edge (12) such that it forms a back clearance angle (ψ) of more than 90° in a feed direction (99), positioning all parts of the turning insert (1) ahead of the nose cutting edge (10) in the feed direction (99), rotating the metal work piece (50) around a rotational axis (A3) in a first direction, and moving the turning insert (1) in a direction parallel to or at an angle less than 45° relative to the rotational axis (A3) such that the first cutting edge (11) is active and ahead of the nose cutting edge (10) in the feed direction (99) and such that the surface (53) at least partly is formed by the nose cutting edge (10).