Drill Flute Arc Geometry for Chip Discharge and Strength
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Solution Overview
Problem
Existing drills face issues with reduced rigidity and strength due to large groove widths in the cut debris discharge groove, leading to potential breakage and clogging, while smaller radii cause scratches and friction, and clogging due to inadequate curvature of the groove surfaces.
Innovation Solution
A drill design featuring a cut debris discharge groove with a concave curve line shape along a first circular arc and a second circular arc, where the first arc has a greater radius, reducing groove width and increasing cross-sectional area, and the point of contact between the arcs is strategically positioned to prevent clogging and friction, ensuring stability and strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the radii of the circular arcs forming the cut debris discharge groove are made large, then the groove width becomes large and the cross-sectional area of the drill body front end section becomes small, but the rigidity and strength of the drill body decrease leading to potential breakage
Solution Approach 1:
The patent applies local quality by creating different curvature radii at different locations within the same groove structure. The first circular arc has a larger radius than the second circular arc, allowing the groove to have adequate width for debris discharge while maintaining structural strength in critical areas. This non-uniform curvature distribution optimizes both debris flow and structural integrity.
Solution Approach 2:
The patent uses curved surfaces defined by circular arcs to form the groove geometry. The smooth curved transitions between different radius sections eliminate sharp corners that would stress-concentrate, while the varying radii optimize both the groove's functional width and the surrounding material's structural strength.
2Strength
If the radii of the circular arcs are made small to reduce groove width and ensure cross-sectional area, then the rigidity and strength of the drill body are improved, but cut debris strongly rubs the inner wall surface forming scratches and causing fractures
Solution Approach 1:
The patent applies local quality by creating different curvature radii at different locations within the same groove structure. The first circular arc has a larger radius than the second circular arc, allowing the groove to have adequate width for debris discharge while maintaining structural strength in critical areas. This non-uniform curvature distribution optimizes both debris flow and structural integrity.
Solution Approach 2:
The patent uses curved surfaces defined by circular arcs to form the groove geometry. The smooth curved transitions between different radius sections eliminate sharp corners that would stress-concentrate, while the varying radii optimize both the groove's functional width and the surrounding material's structural strength.
3Quantity of substance
If the radius of the second circular arc is made smaller than the first circular arc as in JP 4120185 A, then the groove width is reduced, but cut debris pushed into the heel side causes clogging without being sufficiently curled
Solution Approach 1:
The patent applies local quality by creating different curvature radii at different locations within the same groove structure. The first circular arc has a larger radius than the second circular arc, allowing the groove to have adequate width for debris discharge while maintaining structural strength in critical areas. This non-uniform curvature distribution optimizes both debris flow and structural integrity.
Solution Approach 2:
The patent uses curved surfaces defined by circular arcs to form the groove geometry. The smooth curved transitions between different radius sections eliminate sharp corners that would stress-concentrate, while the varying radii optimize both the groove's functional width and the surrounding material's structural strength.
Data Source
Figure 1~2
Figure 3
AI summary
Provided is a drill suitable for high-efficiency working. A cut debris discharge groove (2) is formed in the outer periphery of the drill body front end section (1) rotated about the axis (O), and a cutting edge is formed at the front end of the drill body (1). The wall surface (2A) of the cut debris discharge groove (2), which faces the rotational direction (T) of the drill, is formed to have a concave curve line shape in a cross-section perpendicular to the axis (O), the concave curve line shape extending along a first circular arc (C1). The bottom surface (2C) of the cut debris discharge groove (2), which continues to the wall surface (2A) and which faces the outer peripheral side of the drill body (1), is formed to have a concave curve line shape in a cross-section perpendicular to the axis (O), the concave curve line shape extending along a second circular arc (C2) to be tangent with a core diameter circle (E) at the front end section of the drill body (1). The first circular arc (C1) has a greater radius than the second circular arc (C2) and is in contact with the second circular arc (C2) at a position closer to the leading edge (1A) side than the point (P) of contact between the second circular arc (C2) and the core diameter circle (E).