Cylindrical Cutting Insert with Convex Curved Edges
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Solution Overview
Problem
Cutting inserts with cylindrical base bodies that can be used on both sides often require strong radial and axial tilting, leading to high cutting forces and negative pressure angles, resulting in a hard cutting action and inefficient machining.
Innovation Solution
Designing cutting inserts with straight sections connected to convex curved sections via curved transitions on both sides, featuring a 0° free surface angle and a rake angle between 20° to 30°, along with dome-shaped recesses for indexing, ensures a soft cutting edge engagement and optimal chip formation, reducing cutting forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If cutting inserts are designed to be used on both sides with strong radial and axial tilting, then the number of usable cutting edges is doubled, but the cutting forces increase significantly and the cutting action becomes hard
Solution Approach 1:
The cutting edge is designed with a convex curved profile instead of a straight or concave shape. This curvature allows the cutting edge to engage the workpiece in a progressive manner, distributing the cutting forces more evenly and reducing peak loads. The convex shape enables the cutting insert to achieve a soft cutting action even when installed at strong radial and axial tilting angles, thereby maintaining low cutting forces while utilizing both sides of the insert.
Solution Approach 2:
The invention optimizes specific geometric parameters of the cutting edge, including the convex curvature radius, the transition zones between straight and curved sections, and the rake angle (20°-30°). These parameter adjustments are specifically tailored to reduce cutting forces and achieve a soft cutting action during double-sided usage, directly addressing the force increase problem associated with strong tilting installation.
2Reliability
If cutting inserts are strongly tilted in the tool body, then clearance angle requirements are met for problem-free machining, but a very large negative pressure angle is formed causing hard cutting engagement
Solution Approach 1:
The convex curved cutting edge profile fundamentally changes the engagement geometry between the cutting insert and workpiece. This curvature compensates for the adverse effects of strong tilting by creating a more favorable pressure angle, enabling smooth and progressive cutting engagement even when the insert is installed at strong radial and axial tilting angles required for double-sided usage.
Solution Approach 2:
The invention optimizes the rake angle parameter to be between 20°-30°, which is specifically designed to achieve a soft cutting action during strong tilting installation. This parameter optimization directly addresses the cutting engagement issue by ensuring favorable cutting geometry under the constrained installation conditions of double-sided inserts.
3Ease of operation
If concave cutting edge sections are used in strongly tilted positions, then initial soft cutting action is achieved, but cutting action deteriorates significantly as the cutting edge progresses
Solution Approach 1:
The invention inverts the traditional concave cutting edge design and uses a convex curved profile instead. This convex shape maintains consistent cutting performance throughout the entire cutting edge progression because the outward curvature ensures that the cutting geometry remains favorable from the beginning to the end of the cutting edge life, preventing the deterioration that occurs with concave sections.
Solution Approach 2:
The optimized geometric parameters of the convex curved sections, including the curvature radius and transition zone dimensions, are specifically designed to maintain consistent cutting action throughout the cutting edge life. These parameter changes ensure that the cutting performance does not deteriorate as the cutting edge progresses, directly addressing the consistency problem.
4Ease of manufacture
If straight cutting edges are used in strongly tilted positions, then manufacturing is simplified, but cutting action becomes hard and cutting forces are high
Solution Approach 1:
The invention introduces convex curved sections with specific radius values into the cutting edge geometry, transforming the traditional straight cutting edge design. This curvature modification significantly reduces cutting forces and achieves a soft cutting action during strong tilting installation, while remaining compatible with conventional manufacturing processes through CNC machining or grinding of the curved profiles.
Solution Approach 2:
The invention optimizes the geometric parameters of the curved sections, including the curvature radius, arc length, and transition zone dimensions, to achieve the optimal balance between manufacturing feasibility and cutting performance. These parameter adjustments enable the production of curved cutting edges using standard manufacturing methods while dramatically improving cutting characteristics.
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
The invention relates to a cutting insert for machining, comprising a substantially cylindrical main body having an axis A. The cutting insert has a lateral flank face (1) and opposite rake faces (2, 2'), wherein cutting edges (3, 3') are formed at the intersection of said faces. The cutting edges (3, 3') each have at least two convexly curved sections (4, 4') in the direction of the axis A, which are connected to each other by concavely curved or substantially straight sections (5, 5').