Ret Htec2010 Rufus Gary

7/29/2019 Ret Htec2010 Rufus Gary

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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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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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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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Haas VF1 CNC mill: 5-axis capability

7,500 rpm spindle

25 m spindle runout 3 m repeatability


25 mm @70 from z axis

-120 in x-y plane

x


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Haas SL20 CNC lathe: Live tooling capability

3,400 rpm spindle

3 m repeatability


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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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


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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1

2

Apparatus for Surface tension measurement1. Needle for delivering liquid droplets

2. Camera



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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



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0

10

20

30

40

50

60

70

Water KM CL2200 CL2210EP CL2300HD CL2210 RL1:15

ContactAn

gle()

Tungsten Carbide



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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



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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



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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 + =



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26Balance of adhesion and centrifugal

force on a 2210EP microdroplet



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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



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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


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)




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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


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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.

Ret Htec2010 Rufus Gary

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