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The Influence of High Pressure Coolant on Process Optimization in Heat Resistant Super Alloys (HRSA)
Sean HoltAerospace Application ManagerSandvik Coromant
Agenda
Introduction and history of High Pressure Challenges in Machining
– Operational differences
HPC System requirements, benefits & considerations HRSA machining results & difference with other materials Future trends & directions
2
3
The History of High Pressure Coolant (HPC)
1984 1990 1996 2007 2012
Multi-taskMachining centerTurning center
Pre
ssur
e ba
r (p
si)
500(7250)
100(1450)
Ccoupling for UHPC
VTL
Standard coupling
4
High Pressure CoolantDefinitions
High Pressure Coolant (HPC)up to 80 bar (1160 psi)– Standard option on most machines
• Turning centers• Machining centers• Multi-task machines
– Standard Coromant Capto® coupling– Standard Sandvik Coromant tools available
Ultra High Pressure Coolant (UHPC)over 80 bar (1160 psi )– Standard option for a few machine manufacturers
• Limited to VTLs
– Coromant Capto® coupling for UHPC– Tool holders only as special
5
Pressure (p)Force per unit area– Pascal = N/m2
– Bar = 0.1 MPa (14.5 psi)
Flow rate ()Volume displaced per time unit– liter/min (gallons/min)
Velocity (w)Speed fluid moves through a tube– m/sec (ft/sec)
High Pressure CoolantDefinitions
Kk
()
(w)
6
High Pressure CoolantChallenges in machining
Operation differences:
Turning – continuous single point– Cutting temperature– Chip control
Milling – interrupted multiple teeth– Chip formation– Cutter positioning– Re-cutting of chips – unsecure or short tool life
Drilling – continuous multiple teeth– Varying cutting temperature
• hot periphery• tough center
– Chip control and evacuation through flute
HPC – Machining Requirements
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HPC – System requirements
Pump/machine
– Pressure
– Volume/flow rate
– Filter
Tool
– Nozzle diameter
– Number of nozzles
– Jet flow
– Jet direction
9
HPC – System requirementsPrinciples
Reducing the area increases the velocity
Smaller outlet reduces the pressure and flow rate requirements to achieve a high velocity jet
Flow velocity w1
Flow velocity w1
w2
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Flow expressed in m3/s CD Nozzle efficiency
- 80% 20 to 300 bars (290-4350 psi)
- 70% 300 to 1000 bars (4350-14500 psi)
n Number of nozzles d Nozzle diameter (m) p Pressure (Pa) - 1 bar (100 000
Pa) - 1 psi (6895 Pa) Fluid density - for water and
cutting fluids the density is~ 1000 kg/m3
HPC – System requirementsFlow requirement
The larger the outlet area the greater the flow required to deliver a given pressureThe larger the outlet area the greater the flow required to deliver a given pressure
HPC – Machining HRSAs
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Coromant Capto® Normal coolant inlet
• Hydraulic wedge lifts the chip• Reduces temperature• Improves chip control
High precision jet nozzles
Pre-defined target areas on the insert face
HPC – Turning applications Precision is the power
13
With CoroTurn® HP 70 bars (1160 psi)– Metal removal +50 at same speed– Cutting speed +20% with same total metal removal
HPC – Turning applications Inconel 718 (46HRC) -Total material removed (TMR)
Insert ap fn
CNMX 1204A2-SM S05F 2.5 mm 0.3 mm/rev
CNMX 43A2-SM S05F 0.1 inch 0.012 inch/rev
To
tal
mat
eri
al –
Q (
cm
3)
Surface cutting speed –
Vc (m/min), ft/min
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Normal Pressure 80 bar (1160 psi)
HPC – Turning applications Inconel 718 (46HRC) - Chip control
Insert vc
CNGG 120408 -SGF1105 65 m/min
CNGG 432-SGF 1105 213 sfm
Feed fn (mm/rev)
Cutting depth ap (mm)
0.15 0.2 0.25
2.0
1.0
0.5
0.25Feed fn (mm/rev)
Cutting depth ap (mm)
0.15 0.2 0.25
2.0
1.0
0.5
0.25
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CoroTurn® HP normal pressure
CoroTurn® HP 80 bars, 1160 psi
HPC – Turning applications Inconel 718 (46HRC) - Demonstration
Insert ap fn
CNGG 120408-SGF 1105 0.25 mm 0.15 mm/rev
CNGG 432-SGF 1105 0.01 inch 0.006 inch/rev
HPC – Machining in the Future
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UHPC – Turning applications The basic concept of the technique
UHPC tool - coolant supplied externally into the Coromant Capto® coupling
UHPC blanks - prepared with foursealing seats
80-1000 bar (1160-14500 psi)
HPC tool – internal coolant supply through Coromant Capto ® polygon
80 bar (1160 psi)
Coolant inletUHPC HPC
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UHPC - 230 bar (3300 psi) – 3 minsNormal coolant – 3 mins
UHPC - 300 bar (4350 psi)
UHPC – Turning applicationsEffect on Inconel 718
UHPC - 150 bar (2200 psi)
Summary
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HPC has seen significant improvements in the last few years
New technologies & methods have made machining in HRSAs more efficient
Benefits of using HPC in HRSA machining: Improves chip control Improves tool life Improves cutting speeds
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