Cutting Tool Coolant Hole Geometry for Cooling Without Strength Loss
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Solution Overview
Problem
Cutting tools with increased coolant hole cross-sectional area for improved cooling face reduced tool strength and inefficient coolant distribution, particularly towards the central and outermost peripheral cutting edges.
Innovation Solution
A cutting tool design featuring a coolant supply hole with a kidney-shaped cross-section, where the first portion faces the cutting edge and the second portion is opposite, with a concave portion defined by first and second side portions and a bottom, ensuring effective coolant flow to both central and outermost peripheral areas while maintaining tool strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the coolant hole cross-sectional area is increased to improve cooling effect, then the coolant supply amount increases, but the tool strength is reduced
Solution Approach 1:
The patent changes the geometric parameters of the coolant hole from a conventional circular cross-section to a kidney-shaped cross-section with specific dimensional relationships. The first portion width W1 is set to 0.05D-0.2D, the second portion width W2 is set to 0.1D-0.4D, and the distance L between portions is set to 0.05D-0.2D (where D is the drill diameter). These parameter optimizations increase the total cross-sectional area for improved cooling while distributing the area strategically to maintain structural strength.
Solution Approach 2:
The kidney-shaped coolant hole design creates local quality variations by positioning the first portion (narrower) closer to the cutting edge and the second portion (wider) farther away. This local differentiation allows the coolant to be delivered more effectively to critical cooling zones while the overall shape maintains adequate tool body thickness for strength.
2Temperature
If the coolant hole cross-sectional area is increased to improve cooling effect, then the coolant supply amount increases, but the coolant distribution efficiency deteriorates
Solution Approach 1:
The kidney-shaped coolant hole creates distinct local regions: the first portion (width W1) positioned to serve central cutting edge areas, and the second portion (width W2) positioned to serve outermost peripheral areas. This local quality differentiation ensures that coolant is distributed efficiently to different zones of the cutting edge based on their specific cooling needs, rather than using a uniform cross-section that cannot address localized thermal variations.
Solution Approach 2:
The patent transitions from a simple circular cross-section (one-dimensional symmetry) to a kidney-shaped cross-section with asymmetric dimensional variations. By introducing this dimensional complexity with specific width variations (W1 vs W2) and positioning (distance L), the coolant flow path is optimized to reach both central and peripheral cutting edges effectively, improving distribution efficiency across the cutting circumference.
3Quantity of substance
If the coolant hole cross-sectional area is increased to improve cooling effect, then the coolant supply amount increases, but the tool strength is reduced
Solution Approach 1:
The patent optimizes the geometric parameters of the coolant hole to achieve the maximum cross-sectional area within safe structural limits. The first portion width W1 is set to 0.05D-0.2D and the second portion width W2 is set to 0.1D-0.4D, creating a total area that exceeds conventional circular holes while maintaining adequate wall thickness. The distance L between portions is optimized to 0.05D-0.2D to balance area maximization with structural integrity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The design enhances coolant flow rates to both critical cutting edge areas, maintaining tool strength and facilitating efficient cooling and lubrication, thereby enabling stable and efficient cutting operations, especially on materials with low thermal conductivity like stainless steel.
Implementation Method 1
a coolant supply hole, and a ridgeline between the rake face and the flank face forms a cutting edge
Implementation Method 2
The first portion has a concave portion extending toward the second portion. The concave portion is defined by a first side portion and a second side portion facing each other, and a bottom continuous with both the first side portion and the second side portion.
Data Source
Figure 1
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AI summary
A cutting tool has a rake face and a flank face. The flank face is provided with a coolant supply hole. A ridgeline between the rake face and the flank face forms a cutting edge. An outer shape of the coolant supply hole in a cross section orthogonal to an axis includes a first portion facing the cutting edge, and a second portion opposite to the cutting edge when viewed from the first portion. The first portion has a concave portion extending toward the second portion. The concave portion is defined by a first side portion and a second side portion facing each other, and a bottom continuous with both the first side portion and the second side portion. In the cross section, an angle formed by a tangent of the first side portion and a tangent of the second side portion is not more than 160°.