ret htec2010 rufus gary
TRANSCRIPT
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HTEC Mich_13jul10.pptx
Wayne Hung1, Rufus Lamere2, and Gary SanMiguel3
1Texas A&M University, College Station, TX
2Texas State Technical College, Waco, TX3Biomedical Manufacturing Center, Athens, TX
Present at
The Fourth Annual HTEC Conference
Detroit, Michigan
July 13-15, 2010
Contact: [email protected]
BMC
http://engineering.tamu.edu/ -
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AGENDA
1) Introduction
2) Objectives
3) NSF-RET program4) Investigation
Cutting fluids
Micromist Machinability
5) Summary
6) Future works
Acknowledgement
References
Impact ofMicromist in CNC
Machining
Source: furtech.typepad.com
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3Source: (Marksberry and Jawahir, 2008)
INTRODUCTION
The cost of cutting fluids is around 17% of the
machining costs of automotive components.
1.2 million workers are affected by the chroniceffects produced by cutting fluids.
OSHA demands tighter control on cutting fluids(cost, maintenance, disposal, emission standards)
Propose solution: use micromist as minimumquantity lubrication in machining
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OBJECTIVES
1) Characterize micromist
2) Apply micromist in macro/micro machining3) Identify technical issues
4) Study economics of micromist
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NSF-RET program
1) Is funded by National Science Foundation
2) Provides research experience to teachers/instructors from nearby high schools /community
colleges.
3) Covers 9 weeks in summer
4) Must implement to home institutions
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NSF-RET program (summer2010)
Rufus Lamere, Texas State Technical College, Waco, TX
Gary Miguel, Biomedical Manufacturing Center, Athens, TX
Wayne Hung, Texas A&M University, College Station, TX
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INVESTIGATION: setup
1) Machines: Haas OM2 CNC micromill, VF1 CNC mill, and SL20 CNC lathe.2) Workpieces:
Micromachining: 12 mm (1/2 in) square bars of 316L stainless steel, CP
titanium PEEK plastics, H11 tool steel, 1010 steel, 6061-T6 aluminum.
Macromachining: 4140 steel bars / plates
3) Tools
Micromill: TiN un/coated WC, 100-1016m (0.004-0.040 in)
Microdrill: Uncoated WC 50-203m (0.002-0.008 in)
Macromill: TiN un/coated WC Ingersoll APKT102308R-HS insert, 15.8(5/8 in)
Marcroface: TiN un/coated WC Hertel TNG431 insert
4) Tool failure criteria: 50 m (0.002 in) flank wear for microtool, 300 m(0.012 in) for macrotool.
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INVESTIGATION: setup
5) Machining parameters: Micromilling: 15-157 m/min (50-520 ft/min),10 m/tooth (0.0004
in/tooth), 0.35mm (0.014 in) axial depth, 0.56 mm (0.022 in) radial
depth, climb (down) side milling. Macromilling: 55-102 m/min (183-343 ft/min), 0.043-0.178 mm/tooth
(0.0017-.0070 in/tooth), 1-2 mm (0.04-0.08 in) axial depth, 4.25-8.5 mm
(0.017-0.333 in) radial depth, down milling on D2 tool steel.
Macrofacing: max 44-80 m/min (147-265 ft/min), 0.5 mm (0.020 in)
depth of cut, 0.1-0.3 mm/rev (0.004-0.006 in/rev) feedrate, constant
RPM, on 4140 steel.
6) Cutting fluids: Dry
Flood cooling: synthetic Blasocut 2000 Universal, 5:1 mixture
Micromist: UNIST Uni-MAX system, 2210EP oil, 0.022 cc/min.Use withMistbuster500.
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INVESTIGATION: setup
7) Measurement:
Keyence LK-G82 laser system, 70m beam, 50 kHz sampling
rate, 0.2 m resolution
Olympus STM6 measurement microscope, 0.1 m resolution JEOL JSM 6400 scanning electron microscope
Video tensiometer FTA 188, 001 mN/m accuracy
8) Computer aided tools
SolidWorks, FeatureCam, and MasterCam software
Cosmos finite element software
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INVESTIGATION: machines
3mm (1/8) plug gage @ 10k rpm
Haas OM2 CNC micromill: 5-axis capability
50,000 rpm air spindle
1 m spindle runout 3 m repeatability
Micromist 2210EP oil, 0.022 cc/min
30 mm @60 from z axis
-45 in x-y plane
x
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INVESTIGATION: machines
Haas VF1 CNC mill: 5-axis capability
7,500 rpm spindle
25 m spindle runout 3 m repeatability
Micromist 2210EP oil, 0.022 cc/min
25 mm @70 from z axis
-120 in x-y plane
x
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INVESTIGATION: machines
Haas SL20 CNC lathe: Live tooling capability
3,400 rpm spindle
3 m repeatability
Micromist 2210EP oil, 0.022 cc/min
6 mm @150 from y axis
-60 in x-y plane
z
x
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MICROMACHINING: tool setting
Microtool offset using laser sensor
(b)
Set up for tool height z-offset
xz
y
(a)
Set up for edge detection on x-y plane
x
yz
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MICROMACHINING: tool setting
Edge detection for tool offsets in x, y directions.
-3
-2
-1
0
1
2
3
0 5 10 15 20 25
Trial Number
Deviation
fromM
ean
(m)
Laser on 5/16 inch drill Mechanical edge finder Laser on 1/8 inch plug gage
(mil)
0
-0.1
0.1
X, Y settingsdepend on tool
quality
A precision pluggage should be
used
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-15
-10
-5
0
5
10
15
0 10 20 30
Trial Number
DeviationFromM
ean(m) paper & center drill
paper & 4-insert cutter
laser & drill on membrane
MICROMACHINING: tool setting
Tool height offset in z direction.
Z offset
depends on toolgeometry
Expect a larger
z offset error
than x, y offsets
0.2
0.4
-0.2
-0.4
0
(mil)
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MACHINING: cutting fluid
1) Penetrate the boundary layer of arapidly rotating tool,
2) Adhere to a tool surface despite
centrifugal force, and
3) Wet the tool/chip interface to provide
lubricating/cooling
For effective cooling/lubricating,cutting fluid must:
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xpn = Vf t +M
( V0 cos0 - Vf) [1 - e -( /M) t ]
ypn =M
V0 sin0 [1 - e -( /M) t ]
Particle Trajectory
MACHINING: micromist
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3/1
3
2/32
3/1]
coscos32)cos1(.24[)(
+= K
V
P
V: volume of droplet
P: diameter of dropletK: 1 for900
: contact angle
MACHINING: coolant wetting
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MACHINING: micromist
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1
2
Apparatus for Surface tension measurement1. Needle for delivering liquid droplets
2. Camera
MACHINING: micromist
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0
10
20
30
40
50
60
70
Water CL 1:30 2210 2210EP 2300 HD 2200
ContactAngle
()
Coolant
1mm 1mm 1mm 1mm
316L Stainless Steel
MACHINING: micromist
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0
10
20
30
40
50
60
70
Water KM CL2200 CL2210EP CL2300HD CL2210 RL1:15
ContactAn
gle()
Tungsten Carbide
MACHINING: micromist
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22
6 2
h rV h
h
= +
34
3V R=
V: volume of droplet
h: height of droplet
R: radius of airborne dropletr: (D1+D2)/4
MACHINING: micromist
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0
2
4
6
8
10
12
AverageDiame
ter(m)
Coolants
Coolant drop size comparison
2210 EP
2210
2300 HD
2200
MACHINING: micromist
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(a) Micro-droplet on a rotating tool;
(b) Free body diagram of forces acting on the micro-droplet
a) b)
m: mass of droplet
v: surface speed of tool
R: radius of toolD: diameter of droplet
2: surface tension of liquid
2
22 sin Dmv
R + =
MACHINING: micromist
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26Balance of adhesion and centrifugal
force on a 2210EP microdroplet
MACHINING: micromist
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Parameters of tool wetting experiments:
Tools are run from 0-500 m/min
Tool diameter: 3.175mm, 12.7mm
Air pressure: 3.197 to 3.39 bar
Stroke length: 2.7 mm
Stroke frequency: 12 strokes/min
Volume flow rate of coolant: 3.33 x 10-9 mm3/sec
MACHINING: micromist
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Setup for validation of tool wetting
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(a)Mist spray setup (b) 3.175 mm 2 flute end-mill
12.7mm 2 flute end-mill (not shown)
APPROACH OBJECTIVE # 2
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RESULT: flow of micromist
Direction of flow
@40 m/min
Separation of flow
Dia. 1.016mm cylinder
@4000 RPM
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RESULT: flow of micromist
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MICROMACHINING: tool deflection
End deflection=17% tool diameter
Bending stress= 50% tool strength
End deflection=34% tool diameter
Bending stress= 100% tool strength
Spindle runout, built-up edge, uncontrolled chip, and/or cutting force deflect amicrotool cyclically and cause premature tool failure.
Finite element analysis of bending stress on a micromilling tool.
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MICROMACHINING: limit of parameters
Catastrophic failure threshold of micromilling tools.0.35mm (0.014 in) axial depth, dry , climb (down) side milling of 316L stainless steel.
0
20
40
60
80
100
0 5 10 15 20 25 30
Radialdepth/Cutte
r
(%)
Chipload / Cutter (%)
Axial depth of cut (17% cutter dia)Axial depth of cut (34% cutter dia)Crash test
Tool fracture
Tool safe
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0.00
0.02
0.04
0.06
0.08
0.10
0.12
0 5 10 15 20
#4: dry
#12: flood
#20: mist
Time (min)
wear(m)
0.00
0.02
0.04
0.06
0.08
0.10
0.12
0 5 10 15 20
#5: dry
#13: flood#21: mist
Time (min)
wear(m)
TiN-WC, V3.6m/s, F6.4mm/s, D2mm
TiN-WC, V2.0m/s, F6.4mm/s, D1mm
0.00
0.02
0.04
0.06
0.08
0.10
0.12
0 5 10 15 20
#2: dry
#10: flood
#18: mist
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MICROMIST: macromilling
Time (min)
wear(m)
0.00
0.02
0.04
0.06
0.08
0.10
0.12
0 5 10 15 20
#7: dry
#15: flood#23: mist
Time (min)
we
ar(m)
TiN-WC, V2.0m/s, F12.7mm/s, D2mm
TiN-WC, V3.6m/s, F12.7mm/s, D1mm
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MICROMIST: macrofacing
time(min)
0.00
0.04
0.08
0.12
0.16
0.20
0 20 40 60 80
#2: dry
#6: flood#10: mist
WC on 4140, V0.9m/s max, F0.1mm/rev, D0.5mm
wear(m)
# passes
Dry, 75 passes
Flood, 75 passes
Mist, 75 passes
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MICROMIST: micromilling
Micromilling of 316L stainless steel and effect of cutting fluids.10 m/tooth (0.0004 in/tooth), 0.35mm (0.014 in) axial depth, 0.56 mm (0.022 in) radial depth, climb (down) side milling
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1) NSF-RET program Promote collaboration among schools and industry
Encourage college grads to continue for higher degrees
2) Effective micromist must:
Penetrate and adhere to moving tool/workpiece.
Wet both tool and workpiece.
Avoid stagnant mist location.
3) Optimal micromist increases tool performance Macromachining.
Micromachining.
4) Submicron mist particles Contaminate other equipment.
Pose potential health issues.
Should be used with air cleaner unit.
MICROMIST: summary
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MICROMIST: future works
1) Complete DOE experiment and compare with theoretical data
2) Compare economic advantages of dry, flood, and mist
3) Apply to machines at TSTC Waco and BMC Athens
4) Extend micromilling and include microdrilling studies using tool steel,
aluminum, and titanium.
5) Optimize tool coating
http://engineering.tamu.edu/ -
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ACKNOWLEDGEMENT
National Science Foundation (NSF
award #0552885).
Mr. Dave Hayes, Haas Automation Inc.
Mr. Joe Kueter, M.A. Ford Inc.
Mr. Wally Boelkins, UNIST Inc.
Mr. Patrick Anderson, PMT Inc.
http://engineering.tamu.edu/