Green Cutting using Supersonic Air Jets as Coolant and Lubricant during Turning

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Green Cutting using Supersonic Air Jets as
Coolant andLubricant during Turning
Trinity College Dublin

• Authors Andrea Bareggi (presenter)
• Andrew Torrance
• Garret ODonnell

Department of Mechanical and Manufacturing
Engineering The University of Dublin Trinity
College
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Difficult-to-cut materials
Trinity College Dublin
Introduction

• Heat resistant alloys
• Hard materials
• Super stainless alloys (or super-alloys)

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Difficult-to-cut materials
Trinity College Dublin
Introduction

• Heat resistant alloys
• Hard materials
• Super stainless alloys (or super-alloys)

• Nickel base alloys
• Cobalt base alloys
• Titanium alloys
• Iron base (high chromium stainless steel)

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after Seco Technical Guide, Turning
Difficult-To-Machine Alloy, S. Miller, Advanced
materials means advanced engines,
Interdisciplinary Science Review, vol.21 (2)
(1996) pp.117-129
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Coolants

• Thermal damage

After P. Dahlman, M. Escursell / International
Journal of Machine Tools Manufacture vol.44
(2004) pp.109115
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Coolants

• Thermal damage

• Wearing by friction

After P. Dahlman, M. Escursell / International
Journal of Machine Tools Manufacture vol.44
(2004) pp.109115
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Trinity College Dublin
Coolants

• Thermal damage

• Wearing by friction

• Built up edges

After P. Dahlman, M. Escursell / International
Journal of Machine Tools Manufacture vol.44
(2004) pp.109115
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Trinity College Dublin
Coolants

• Thermal damage

• Wearing by friction

• Built up edges

• Sweeping and cleaning the chip-tool interface

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Trinity College Dublin
Improving cooling techniques

• Reducing cutting forces
• Reducing tool wearing
• Reducing workpiece temperature
• Reducing costs
• Reducing environmental impact

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Using air jets why?

• Good for environment
• Not toxic for the operator
• Cheap
• Good for chip sweeping
• More likely to penetrate into the chip-tool
  interface
• Capable of accelerating fluid particles to give
  better heat transfer

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Experimental apparatus

• Ursus 225 Centre Lathe
• Kistler piezoelectric tool-force dynamometer
• WC inserts with different nose radius
• Supersonic nozzle Silvent 1011
• Hommel roughness tester
• Infrared camera

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Test setup

• Cutting speed 270 m/min
• Depth of cut 0.5 mm
• Feed 0.095 mm/rev
• Insert nose radius 0.4 mm
• Rake angle 5
• Air jet pressure (nozzle inlet) 6 bar
• Insert material WC
• Workpiece material AISI1020 steel

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Experimental Results

• Force
• Small reduction of forces, when using air jets

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Experimental Results

• Force

• Finishing
• Without jet Ra 0.83µm
• With jet Ra 0.75 µm

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Experimental Results

• Force

• Finishing

• Chip shape and colour

Air jet off
Air jet on
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Experimental Results

• Force

• Finishing

• Chip shape and colour
• Thermo-Camera

Air jet on
Air jet off
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Finite Element Model

• Deform-3D
• Arbitrary Lagragian Eulerian formulation
• adaptive non-linear remeshing algorithm
• fully coupled thermo-mechanical analysis

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Trinity College Dublin
Finite Element Model
Finite Element Model

• Deform-3D
• Arbitrary Lagragian Eulerian formulation
• adaptive non-linear remeshing algorithm
• fully coupled thermo-mechanical analysis
• Force prediction

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Finite Element Model

• Femlab3.1
• Frictional power
• Estimated specific cutting energy
• Heat transfer by formed chip
• Thermal power generation in the chip-tool
  interface area

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Conclusions Further Research

• Heat transfer by impinging jet

• Fluid-dynamic data
• Estimated Nusselt number
• Temperature measurement with hot-spot radiometer

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Conclusions Further Research

• Heat transfer by impinging jet
• Chip shape and shear plane investigation

• Beneficial effect of the force applied on the
  chip by the air jet
• Quick-stop tests

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Conclusions Further Research

• Heat transfer by impinging jet
• Chip shape and shear plane investigation
• Improve the FE modeling

• Modeling the air jet effect (Deform)
• Improving the friction model (Deform)
• Improve heat transfer model in chip-tool
  interface (Femlab)
• Develop a fluid-structure interaction model
  (Femlab)

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Conclusions Further Research

• Heat transfer by impinging jet
• Chip shape and shear plane investigation
• Improve the FE modeling
• Testing

1. Cutting parameters
2. Workpiece and insert standard materials
3. Air jet positioning
4. Investigating the use of atomized fluids
5. Investigating the use of two nozzles overhead
   and flank configuration

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Conclusions Further Research

• Heat transfer by impinging jet
• Chip shape and shear plane investigation
• Improve the FE modeling
• Testing
• Advanced testing

1. Nickel base alloys cutting
2. Other machining applications

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Conclusions Further Research

• Thank you for the attention

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