Broaching Tool Lubrication Channels for Cutting-Zone Wear Reduction

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Solution Overview

Problem

Conventional broaching techniques in the aeronautical industry face issues such as tool damage, including chipping and breakage, due to inadequate lubrication at the cutting zone, leading to geometric and material integrity issues, and increased machining costs.

Innovation Solution

A broaching tool with internal lubrication channels that supply lubricant under high pressure directly to the cutting zone, optimizing lubrication by distributing outlet ports away from the cutting face, and a lubrication system that delivers lubricant as close as possible to the cutting zone.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional broaching techniques are used without internal lubrication channels, then the tool structure is simpler, but tool damage occurs due to inadequate lubrication at the cutting zone

Engineering Contradiction:
Improvetool lifeVSAvoidtool structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The broaching tool is segmented into multiple functional zones with separate lubrication channels for each cutting zone. Each channel independently delivers lubricant to specific cutting faces, allowing precise lubrication control without compromising overall tool structural integrity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The lubrication channels are nested within the broaching tool body, with inlet ports, channels, and outlet ports integrated into the tool structure. This nesting approach delivers lubricant directly to cutting zones without external lubrication systems, reducing space requirements while maintaining reliability.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Object-affected harmful factors

If lubricant is supplied from outside the broaching tool, then the lubrication system is simpler, but the lubricant cannot reach the cutting zone effectively

Engineering Contradiction:
Improvefriction and heat at cutting zoneVSAvoidlubrication system
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The lubrication channels act as intermediaries, transporting lubricant from the external supply system directly to the cutting zone through the tool body. This intermediary structure overcomes the limitation of external lubrication by creating a direct delivery path that eliminates lubrication gaps.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The lubrication system utilizes hydraulic principles to deliver lubricant under pressure through the internal channels. The pressurized lubricant flow ensures effective delivery to the cutting zone, reducing friction and heat generation without requiring complex mechanical lubrication mechanisms.

Inventive Principle:
Principle #29Pneumatics and hydraulics

3Productivity

If multiple cutting edges are used in broaching, then material removal efficiency is improved, but tool damage increases due to accumulated thermomechanical stresses

Engineering Contradiction:
Improvematerial removal rateVSAvoidtool resistance to damage
Core Design Contradiction:
ProductivityVSStrength

Solution Approach 1:

Lubricant is supplied to the cutting zones before and during the cutting process through the internal channels. This preliminary lubrication action reduces thermomechanical stresses on the cutting edges before they engage the workpiece, preventing chip adhesion and reducing tool damage while maintaining high material removal rates.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The lubrication system changes the physical parameters at the cutting interface by introducing lubricant that reduces friction and heat generation. This parameter change allows multiple cutting edges to operate at higher speeds and loads without accumulating damaging thermomechanical stresses, thereby increasing productivity while protecting tool strength.

Inventive Principle:
Principle #35Parameter changes

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

Reduces tool damage, extends tool life, minimizes chip size, and decreases machining time and costs by enhancing lubrication efficiency and reducing friction and heat generation.

Implementation Method 1

a plurality of lubrication channels associated with the or each cavity and intended to be supplied with lubricant

Methodology Applied
Scientific EffectLubrication: Lubrication

Implementation Method 2

decreases machining time and costs by enhancing lubrication efficiency and reducing friction and heat generation

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 3

supplying lubricant under high pressure as close as possible to the cutting zone

Methodology Applied
Scientific EffectPressure Increase: Pressure Increase

Data Source

PatentEP3946789B1Broaching tool, broaching machine comprising such a tool and method for machining a workpiece using such a machine
Publication Date: 2025.09.03 SAFRAN AIRCRAFT ENGINES SAS
  • EP3946789B1 patent drawingFigure 1~2
  • EP3946789B1 patent drawingFigure 3
  • EP3946789B1 patent drawingFigure 4~5

AI summary

The invention relates to a broaching tool (20) comprising: - at least one cutting zone (22) comprising a cutting face (24; 24a, 24b, 24c) which is intended to come into contact with a workpiece (1) in order to remove material from the workpiece, - at least one cavity (26; 26a, 26b, 26c) corresponding to the cutting zone, the cavity being arranged so as to receive the removed material, - a plurality of lubrication channels (28; 28a, 28b, 28c, 28d; 28') which are intended to be supplied with lubricant, each lubrication channel having an inlet opening (30) which is arranged to receive the lubricant and at least one outlet opening (32) which opens into the cavity, the tool being characterised in that the distance between the outlet openings of two consecutive lubrication channels varies further from or closer to the cutting face.