Asymmetric Drill Tip Geometry for Low-Torque Precision Holes
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Solution Overview
Problem
Cutting tools with improved centripetal properties often compromise on rigidity, leading to increased torque and larger burr sizes during the perforation process, especially when the point angle is reduced.
Innovation Solution
A cutting tool design featuring a drill body with a cutting portion that includes radially extending chisel edges, relief faces, and chip exhaust grooves, where the first point angle is smaller than the second point angle, and the chisel edges are inclined at different angles to enhance centripetal properties and rigidity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the point angle of the cutting tool is reduced to improve centripetal property, then the precision in hole size and shape is improved, but the rigidity of the cutting portion is lowered
Solution Approach 1:
The patent applies asymmetry by configuring the relief faces and chisel edges at different angles and positions. Specifically, the first and second relief faces are inclined at different angles relative to the rotational axis, and the chisel edges are positioned asymmetrically to optimize both centripetal property and rigidity simultaneously, breaking the conventional symmetric design that forces a trade-off between these two parameters.
Solution Approach 2:
The patent implements local quality by creating different geometric characteristics in different regions of the cutting portion. The chisel edges have specific inclinations and the relief faces have varying angles in different zones, allowing each local region to contribute differently to overall performance - some areas optimized for centripetal property while others maintain rigidity.
2Manufacturing precision
If the point angle of the cutting tool is reduced to improve centripetal property, then the precision in hole size and shape is improved, but the torque of the cutting tool increases
Solution Approach 1:
The asymmetric configuration of relief faces and chisel edges distributes the cutting forces more evenly during rotation. The varying angles of the relief faces (first relief face at one angle, second relief face at a different angle) create a more balanced force distribution that reduces peak torque while maintaining the small point angle needed for precision hole formation.
3Manufacturing precision
If the cutting tool has a small point angle to improve centripetal property, then the precision in hole size and shape is improved, but the size of burr generated increases
Solution Approach 1:
The patent uses local quality by creating specific geometric features at critical locations. The chisel edges are configured with particular inclinations and the relief faces have specific angle variations in different zones, ensuring that the cutting action at the tip (where burr formation occurs) is optimized to minimize burr generation while maintaining the small point angle for precision.
Data Source
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AI summary
A cutting tool including an improved centripetal property and rigidity is provided. The cutting tool includes a drill body rotating about an imaginary rotational axis, and a cutting portion located at a leading edge side of the drill body, wherein the cutting portion includes a first grinding face including a first chisel edge radially extending from the rotational axis and a second chisel edge radially extending from the rotational axis and defining a predetermined angle with the first chisel edge, a second grinding face including a third chisel edge disposed to be point-symmetrical to the first chisel edge in terms of the rotational axis and a fourth chisel edge disposed to be point-symmetrical to the second chisel edge in terms of the rotational axis, a first relief face radially extending from the first chisel edge and the fourth chisel edge and including a first cutting edge formed at a front of a rotation direction of the drill body, a second relief face meeting a rear of the rotation direction of the first relief face, a third relief face radially extending from the second chisel edge and the third chisel edge, including a second cutting edge positioned at the front of the rotation direction of the drill body and disposed to be point-symmetrical to the first relief face in terms of the rotational axis, a fourth relief face meeting the rear of the third relief face in the rotation direction, a first intersection line formed along a boundary where the first relief face and the second relief face meet, and a second intersection line formed along a boundary where the third relief face and the fourth relief face meet, wherein the first intersection line and the second intersection line are spaced apart from an imaginary center line passing the rotational axis, the first relief face and the third relief face.