Cutting Tool Coolant Hole Geometry for Flow and Strength
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Solution Overview
Problem
Cutting tools with coolant holes face a challenge in increasing coolant flow rate to efficiently supply coolant to the central and outermost peripheral portions of the cutting edge while maintaining tool strength, as larger coolant holes reduce the tool's thickness and strength.
Innovation Solution
A cutting tool design featuring a coolant supply hole with a kidney-shaped cross-section, where the first portion facing the cutting edge has a concave portion extending toward the second portion, and the angle between the tangents of the side portions is not more than 160°, allowing effective coolant distribution while maintaining tool strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the coolant hole cross-sectional area is increased to increase coolant supply amount, then the coolant supply efficiency is improved, but the tool thickness and strength are 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 ratios. The first portion (facing the cutting edge) has a cross-sectional area that is 0.6 to 0.8 times that of the second portion, creating an optimized flow distribution that increases coolant supply to the cutting edge while maintaining overall hole area within acceptable limits for tool strength
Solution Approach 2:
The coolant hole employs an asymmetric kidney-shaped cross-section where the first portion (near the cutting edge) and second portion (away from the cutting edge) have different cross-sectional areas. This asymmetric design creates a pressure gradient that directs more coolant flow toward the cutting edge, resolving the contradiction between increasing coolant supply and maintaining tool strength by concentrating flow where needed rather than uniformly increasing the entire hole area
2Ease of operation
If the coolant hole cross-sectional area is increased to supply coolant to outermost peripheral portions, then the coolant distribution is improved, but the tool thickness is reduced
Solution Approach 1:
The patent applies local quality by creating different cross-sectional areas at different locations along the coolant hole. The first portion near the cutting edge has a smaller cross-sectional area (0.6-0.8 times the second portion), while the second portion has a larger area. This local variation in geometry optimizes coolant distribution to reach the outermost peripheral portions effectively without requiring a uniform increase in the entire hole dimensions that would compromise tool thickness
Data Source
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°.