Rotating Cutting Tool Cooling Channels for Higher Edge Heat Transfer

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Solution Overview

Problem

Current cooling channel designs in cutting tools are ineffective due to low heat transfer coefficients and inefficient coolant delivery to the hottest regions of the cutting edge, requiring high energy consumption for fluid delivery in multi-axis milling centers.

Innovation Solution

The cooling channel features an elongated cross-sectional shape with an elliptical portion proximate the cutting edge, utilizing centrifugal force to propel coolant into the nucleate boiling region, enhancing heat transfer and thermal energy removal.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If circular cross-section cooling channels are used, then the tool structure is simple and easy to manufacture, but the heat transfer coefficient is low and cooling effectiveness is poor

Engineering Contradiction:
Improveheat transfer coefficientVSAvoidcooling channel design complexity
Core Design Contradiction:
TemperatureVSEase of manufacture

Solution Approach 1:

The patent applies asymmetry by changing the cooling channel cross-section from a conventional circular shape to an elongated shape with aspect ratios between 2:1 and 10:1. This asymmetric geometry creates non-uniform flow distribution that enhances heat transfer coefficients by maintaining the coolant in the nucleate boiling region longer and improving contact with the cutting edge surfaces.

Inventive Principle:
Principle #4Asymmetry

2Reliability

If high pressure coolant delivery is used, then coolant can be delivered to the cutting area, but energy consumption increases significantly

Engineering Contradiction:
Improvecoolant delivery effectivenessVSAvoidenergy consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent applies dynamics by utilizing the rotational motion of the cutting tool itself to generate centrifugal forces that propel coolant through the channels and out to the cutting edges. This dynamic approach converts the tool's rotational kinetic energy into coolant flow pressure, eliminating or reducing the need for high-power coolant pumps while maintaining reliable coolant delivery.

Inventive Principle:
Principle #15Dynamics

3Temperature

If conventional cooling channels are used, then coolant is delivered to the cutting area, but the coolant does not reach the hottest regions effectively

Engineering Contradiction:
Improvecoolant delivery to hottest regionVSAvoidcooling channel configuration
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The patent applies local quality by positioning the elongated cooling channels specifically along the cutting edges where heat generation is most intense. The channels are configured to deliver coolant directly to the tooth root and cutting edge regions, ensuring that the hottest areas receive the most cooling. The elongated geometry allows coolant to be distributed along the length of the cutting edge rather than just at discrete points.

Inventive Principle:
Principle #3Local quality

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

This design improves heat transfer rates, reduces energy consumption, and increases material removal rates, leading to lower costs, higher productivity, and reduced coolant usage, while minimizing thermal shock and extending tool life.

Implementation Method 1

The at least one cooling channel may be configured such that a centrifugal force propels the liquid coolant into the elliptical portion

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Implementation Method 2

The elongated cross sectional shape of the at least one cooling channel may be configured to maintain a liquid coolant within a nucleate boiling region

Methodology Applied
Scientific EffectNucleate boiling: Boiling

Data Source

PatentEP3736067B1Design for internal cooling passages for rotating cutting tools
Publication Date: 2024.05.15 RTX CORP
  • EP3736067B1 patent drawingFigure 1~4
  • EP3736067B1 patent drawingFigure 5~8
  • EP3736067B1 patent drawingFigure 9~11

AI summary

A cutting tool comprising a tool body (10) comprising a shank (12) and a cutter (14) opposite the shank (12), the body (10) defining a length (L) from a shank end (16) to an end face (18) opposite the shank end (16), a central axis extends along the length (L) of the body (10); at least one tooth (22) having a cutting edge (24), the cutting edge (24) extending along the tooth (22) from the shank (12) to the end face (18); a flute (26)formed adjacent the at least one tooth (22); at least one cooling channel (30) formed in the tooth (22) proximate the at least one cutting edge (24), the at least one cooling channel (30) having an elongated cross sectional shape with an elliptical portion (32) and a circular portion (34) opposite the elliptical portion (32), wherein the elliptical portion (32) is located proximate the cutting edge (24).