Rotary Cutting Insert Geometry for Negative Rake Machining
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Solution Overview
Problem
Existing rotary tools face challenges in maintaining cutting performance while avoiding the peripheral surface of the cutting insert from coming into contact with the workpiece, particularly when setting a large negative axial rake.
Innovation Solution
The rotary tool design includes a holder with a pocket for a cutting insert, where the insert features a convex upper and lower surface with specific end locations and lateral surfaces, allowing for a recessed tip region that enables a small negative axial rake without compromising cutting performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the axial rake is set to a large negative value to avoid the peripheral surface from contacting the workpiece, then the risk of lateral surface contact is reduced, but cutting performance deteriorates
Solution Approach 1:
The cutting insert employs different surface configurations in different regions: the peripheral surface has a specific curvature radius (R1) to control contact, while the lateral surface has a different curvature radius (R2) to optimize cutting performance. This local differentiation allows each surface to be optimized for its specific function without compromising the other.
Solution Approach 2:
The invention transitions from controlling only the axial rake angle (one-dimensional parameter) to incorporating radial curvature radii (R1 and R2) as additional control dimensions. By defining specific curvature radii for different surfaces, the solution adds radial dimension control to the traditional axial rake control, enabling simultaneous optimization of both contact avoidance and cutting performance.
2Object-affected harmful factors
If the cutting insert is bent largely forward to avoid peripheral surface contact, then the lateral surface contact is prevented, but cutting performance is lowered
Solution Approach 1:
The cutting insert employs different surface configurations in different regions: the peripheral surface has a specific curvature radius (R1) to control contact, while the lateral surface has a different curvature radius (R2) to optimize cutting performance. This local differentiation allows each surface to be optimized for its specific function without compromising the other.
Solution Approach 2:
The invention transitions from controlling only the axial rake angle (one-dimensional parameter) to incorporating radial curvature radii (R1 and R2) as additional control dimensions. By defining specific curvature radii for different surfaces, the solution adds radial dimension control to the traditional axial rake control, enabling simultaneous optimization of both contact avoidance and cutting performance.
Data Source
AI summary
A rotary tool may include a holder and a cutting insert. The cutting insert may include an upper surface including a first upper side, a lower surface including a first lower side, and a lateral surface. The lateral surface may include a first lateral surface, a second lateral surface, and a third lateral surface. The first upper side may include a first end. The first end may be located closer to the third lateral surface than the second lateral surface. The first lower side may include a second end. The second end may be located closer to the second lateral surface than the third lateral surface. In a front view of the upper surface, the first lateral surface may include a tip region surrounded by the first end and the second end, and the tip region may be recessed toward the rear end.