Machni ni g Technool gy of r Aerospace and Auto Parts ... Technology for Aerosp… · Professor, Manufacturing Research Center, Tokyo Denki University. Emeritus Professor, The University

Machining Technology for Aerospace and Auto Parts Manufacturing

Auto Parts Tech Day 2017August 8-10, 2017

Thailand Science Park (TSP)Pathum Thani, Thailand

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Toshiyuki ObikawaProfessor, Manufacturing Research Center, Tokyo Denki University

Emeritus Professor, The University of TokyoEmeritus Professor, Tokyo Institute of Technology

Member of Science Counsel of Japan

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> Aircraft industry and its manufacturing research and development

> Machining of airframe partsR & D at the University of Tokyo

> High speed machining; You should not reduce cutting speed.

> High pressure coolant technology: cost-effective machining

> Summary

Overview

2

Aircraft production in the world

3

Forecast of jet aircrafts from 2012 to 2031 （Source: Japan Aircraft Development Corporation）

> Commercial aircraft industry is expected to grow at 5% annually.> New 39,620 airplanes, valued at $5.9 trillion will be delivered by 2035.

Number of aircrafts Number of seats

> 400

310 - 400

230 - 309

170 - 229

120 - 169

100 - 119

60 - 99

20 - 59

ForecastActual

New airplanes

Retained airplanes

Aircraft production in Japan

4

2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016

Total

Commercial

DefenseProd

uctio

n va

lue

Year

[100 million yen]

Production value of airplanes (airframes and engines) in Japan [in 100 million yen] （Source: Aerospace Industry Database, The Society of Japanese Aerospace Companies, 2017）

13,030

18,000

16,000

14,000

12,000

10,000

8,000

6,000

4,000

2,000

0

> Production value of commercial airplanes in Japan sharply grows from 2011 to 2015.> Innovative high-efficiency manufacturing processes are needed to meet the rapid

increase in the amount of production.

787

Global research centers

5

Rolls Royce The Manufacturing Technology Centre (MTC) 2011-(1) Universities of Nottingham, Birmingham and Loughborough, and TWI(2) High integrity joining, intelligent automation, powder net shape manufacture, etc.(3) Rolls-Royce, Airbus & Aero-Engine Controls, etc.

The Commonwealth Center for Advanced Manufacturing (CCAM) 2012-(1) University of Virginia, Virginia Tech and Virginia State University(2) Surface engineering, advanced manufacturing systems and related technologies(3) Rolls-Royce, Newport News Shipbuilding, Canon, Sandvik Coromant, etc.

The Advanced Remanufacturing & Technology Centre (ARTC) 2013-(1) Singapore Institute of Manufacturing Technology (SIMTech), A*STAR(2) Repair and restoration, surface modification & product verification(3) Rolls-Royce, Boeing and Siemens

The Advanced Manufacturing Research Centre (AMRC) 2001-(1) The University of Sheffield(2) Machining, Metrology, Assembly, Composite material, Design & Prototyping, etc.(3) Rolls-Royce (“Factory of the Future” was open in 2008), Boeing, Airbus, etc.

The National Composites Centre (NCC) 2011-(1) University of Bristol(2) Advanced composites design, structural analysis, modelling and simulation, etc.(3) Rolls-Royce, Airbus, GKN, Agusta Westland, Umeco, etc.

The Advanced Forming Research Centre (AFRC) 2011-(1) University of Strathclyde(2) Forming and forging of metals, materials characterization and process modelling(3) Rolls-Royce, Boeing, Aubert & Duval, Barnes Aerospace, etc.

The Nuclear Advanced Manufacturing Research Centre (Nuclear AMRC) 2012-(1) Universities of Sheffield and Manchester(2) —(3) EDF, Areva, Rolls-Royce, Sheffield Forgemasters International Ltd, etc.

AMRC with Boeing, Rolls-Royce Factory of the Future

Boeing12 global research centers out of the US.

ARTC, SIMTech & A*STAR, Singapore2013 -

CMI, the University of Tokyo, Japan2013 -

Research funds: partner companies, governments, funding agencies

Collaborative Research Center for Manufacturing Innovation (CMI), Institute of Industrial Science, the University of Tokyo

6

CFRPEf

ficie

ncy

and

Econ

omic

sInnovative Manufacturing

Technology of Aircrafts

High value manufacturing

SustainabilityIntelligence

and Flexibility

NDI - CFRP parts

Hot forming & Welding- Titanium alloy

High speed machining - CFRP- Titanium alloy- Al-Li alloy

Robotics- Sealing- Milling

Members of CMI> Academia

Institute of Industrial Science, the University of Tokyo

> Aircraft (4)Boeing, Mitsubishi Heavy Industries, Kawasaki Heavy Industries, SUBARU

> Machine tool (1)DMG MORI

> Cutting tool (5)Sandvik Coromant, OSG, Sumitomo Electric Hardmetal,

Mitsubishi Material, NACHI-FUJIKOSHI> Material and Cutting fluid (3)

TORAY, Kobe Steel, Idemitsu Kosan> Small and medium companies (12)

Consortium for Manufacturing Innovation

7


> Machining of airframe parts: R & D at the University of Tokyo1. Drilling of CFRP2. Pocket milling of titanium alloy and aluminum alloy3. Machining of Al-Li alloy

> High speed machining; do not reduce the cutting speed


> Summary

Overview

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9

Drilling of carbon fiber reinforced plastic (CFRP)> CFRP is used for Boeing 787 up

to 50 wt%. > Tremendous number of holes

are made on CFRP plates for joining during assembly processes.

> CFRP is one of difficult-to-machine materials because a carbon fiber has a very high strength, about 10 times higher than steel.

> Troubles in drilling CFRP:delamination, uncut fiber,spalling, uncut resin, burn, rapid tool wear

http://articles.sae.org/5907/

http://www.carbonfiber.gr.jp/field/images/plane02_b.jpg

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Drilling of CFRP (2)> Optimization

Tool geometryTool material, coating material (diamond coated drill)Drilling conditionsDrilling method (axial drilling or orbital drilling) for large holes and stack plates

Drill geometry for reducing thrust force and avoiding delamination at tool exit.Drill geometry may change position to position when the thickness of CFRP and the hole diameter to be drilled are different.

Orbital drilling Orbital drilling machine

http://www.makotoloy.co.jp/kougu.html

(Helical milling) http://www.novator.eu/products/portable-orbital-drilling-systems__73http://www.novator.eu/

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Drilling of CFRP (3)> Prediction system based on the energy approach for optimizing drilling processes> Chip formation, chip flow direction, cutting forces (thrust and torque), cutting

temperature, tool wear, delamination at the exit hole are predicted in about 10 min.

Prediction system of axial drilling, (end milling and orbital drilling) of CFRP

High Speed Machining Technology Development of Difficult-to-Machine Materials for Aircraft (FY2015), published by the New Energy and Industrial Technology Development Organization (NEDO), Japan

12

Drilling of CFRP (4)

> Calculated results for axial drilling

Drilling forces

Drill wearSizes of delamination


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(a) 124 sec (b) 248 sec (c) 372 sec (d) 496 sec

> Drilling of stack plates of CFRP and titanium alloy is one of difficult jobs.> High cutting temperature during drilling titanium alloy may cause the burn

of CFRP.> Prediction of cutting temperature in drilling the stuck plates is useful for

determining drilling conditions.

Drilling of CFRP (5)

Temperature in drilling pre-holed stack plates of Ti/CFRP/Ti


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> Drastic increase in the amount of titanium alloy used for CFRP aircrafts> Certain amount of aluminum alloy is replaced by titanium alloy to avoid

High speed pocket milling of titanium alloy

Others

Composite materials

Titan

Steel

Aluminum

Changes in structural materials of Boeing’s aircraft（Source: The society of Japanese Aerospace Companies)

1. Galvanic corrosion due to the difference of electric potential between aluminum alloy and CFRP

2. Large thermal deformation due to the difference of linear expansion coefficient between aluminum alloy and CFRP

> Titanium alloy to be machined787: 90-120 ton （Mid-size aircraft）777: 60-70 ton A380: 80 ton

*About 85% of titanium are removed as chips during machining process, e.g., 100 ton 15 ton.

2. Pocket milling with minimum mismatch or free from mismatch

3. Environment friendly machining:High speed machining using mist coolant promoting lubrication and cooling as well as reducing thermal impact to an end mill.

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> New strategies for high efficiency pocket milling with reduced cost

High speed pocket milling of titanium alloy (2)

1. Pocket milling with minimum hand finishing or free from hand-finishing Rough machining finish machining hand finishing

Rough machining finish machining

Mismatch is a step on the machined surface, larger than 25 µm (1/1000 inch), caused between machining processes.

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Achievement （evaluated by operation time）

～30%

50%

～90%

> Achievement（evaluation by operation time）1. Finish machining technology without mismatch has

been established.Hand finishing: reduction by 50%.

(Hand finishing except pocket milling area is needed)Finish machining: reduction by about 90%.

2. Rough machining: reduction by about 30%.3. Total time: reduction by about 50%.

> Pocket milling for evaluating new machining method


Chip removal up to 500 cc/min

High efficiency rough milling of titanium alloy 5-axis rough machining of Ti-6Al-4V by Makino Milling Machine

http://www.makino.co.jp/jp/processing/parts/07.html

- 5-axis machining center with high torque at low rotational speed

- Roughing end mill 80 mm in diameter with five flutes

- Spindle speed in machining: 240 min-1

(cutting speed 60.3 m/min)- Fees speed 144 mm/min- Axial depth of cut 80 mm- Radial depth of cut 20 mm - Chip removal rate 230 cc/min

Tool life is around 60 min.

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18


30 mm for titanium alloy Ti-6Al-4V

50 mm for aluminum alloy 7075

> Depth of cut without chatter vibration in milling pockets with 3 mm-thick thin walls:


Titanium alloy Ti-6Al-4V

aluminum alloy 7075End mills tested

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Machining of Al-Li alloy> Large distortion of Al-Li alloy after machining

Size of distortion: Al alloy < Al-Li alloy < titanium alloy1. Thermal conductivity: Al-Li alloy < Al alloy

→ High cutting temperature in machining Al-Li alloy.2. Large residual stress generated by machining

In case of thin plate cutting, generally,residual stress by machining is larger than that by rolling.

3. Adhesion is stronger for Al-Li alloy than Al alloy.4. Reforming Al-Li work after machining and lower cutting speeds increases the cost

of machining.

Ti-6Al-4V (GE Aviation)

> Elimination of distortion is one of most difficult themes in cutting technology.> Application of FEM expects to clarify cutting phenomena and the mechanism of

residual stress generation.> Milling experiments and measurement of residual stresses with X-ray Residual Stress

Analyzer

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Machining of Al-Li alloy (3)

> Achievement1. Distortion was reduced by more than 30%.2. Finite element method has been established for evaluating the distortion of Al-Li thin plate.

Flank wear

Small

Large

OptimizedNot optimized

Geometry of cutting edgeD

efor

mat

ion

Reduction of distortion

Reduction of deformation

Reduction of residual stress by tool geometry optimization （ FEM analysis）

Optimized tool geometry

Conventional tool geometry



> Machining of airframe parts: R & D at the University of Tokyo



> Summary

Overview

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High speed turning of cast iron with CBN tool

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> Tool life curvesby K. Karino

Tool life

Cutt

ing

spee

d

Work: Gray cast iron FC250, 148HBTool: Poly-crystalline cBN (MB730), SNGN120408Tool holder: CSBNR2525M43Cutting conditions: ap = 0.50 mm, f = 0.10 mm/rev

Tool life criterion:Width of flank wear VB = 0.3 mm

Tool wear mechanism (1)

23 THC Childs et al., Metal machining, Arnold (2000)

Cutting temperatureOptimum temperature

Wea

r rat

e> Strong adhesive wear of a tool changes the strategy of selecting

cutting speed.

Machining of hood mold

http://www.marubeni-sys.com/de/gom/jirei/atos_rf02.html

> A large hood mold is usually made of ductile cast iron.Its finishing requires long time and change of ball end mills several times due to tool wear.

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High speed milling of hood mold using CBN radius end mill

(1) Tool life extensionTiAlN ball end mill CBN ball end mill

(2) Increase in cutting speedCBN ball end mill CBN radius end mill

Work: FCD540

Tool life cutting length [m]

cBN tool

Cutt

ing

spee

d [m

/min

] TiAlN: tool life curve

CBN ball end mill

CBN: tool life curve

Tool life extension

by N. Sunahara

Tool life cutting length [m]

Cutting speed

Cutting speed [m/min]

CBN radius end mill increases cutting speed

CBN ball end mill

CBN: tool life curve

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Hard turning using CBN insert

http://www2.coromant.sandvik.com/coromant/pdf/Hard_part_turning/C-1040-069.pdf

26

> Turning of hardened steelChip color indicates that the cutting temperature is very high.Coolant except high pressure coolant should not be applied to avoid thermal shock to the insert.

Hard turning of AISI52100 (HRC62) with CBN tool by Egawa

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> The optimum cutting speed with the minimum wear is 80 - 100 m/min.> Serrated chips are formed under the optimum cutting speeds.

(a) Width of flank wear (b) Chip formationCutting conditions: depth of cut 0.15 mm, feed rate 0.10 mm/rev, Dry

Cutting speed 15 m/min Cutting speed 50 m/min

Cutting speed 75 m/min Cutting speed 150 m/minCutting speed

Wid

th o

f fla

nk w

ear

: Position of maximum chip thickness

: End cutting edge

Cutting length 600 m

Tool wear mechanism (2)

28

Critical speed

Cutting speed

Serrated chip

Tool

life

cut

ting

leng

th

Flow type chip

> Change in chip formation from flow type chip to serrated chip may reduce the chip load to extend the tool life.

Cutting temperature in hard turning

29

> Change in cutting temperature with work hardness by N. NarutakiCutting temperature reduces when steel is harder than HRC50.

Cutting temperature in hard turning (2)

30

> Cutting temperature begins to reduce when the serrated chips are formed.

Chip formation obtained by N. Narutaki

Hard skiving

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> New machining technology of hardened steel using a long straight cutting edge of CBN tool developed by Sumitomo Electric Industries, Ltd.Feed marks do not remain on the machined surface.

https://www.youtube.com/watch?v=d_fVuSyMHZE

> Work: AISI4I35（HRC60）

> Tool:CBN with Straight long edge

Video:

Hard milling of pre-hardened steel by Takeoka

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> Work: SKD61（HRC35）> Tool: Ball end mill, TiAlN coated carbide,

2 mm in diameter

Cutting conditions: ap 0.5 mm, ae 0.5 mmCutting speed is 163 m/min at tool rotational speed 30,000 min-1.

Spindle rotational speed [min-1]

Tool

life

cut

ting

leng

th [

m]

Feed speed [mm/min]

Tool

life

cut

ting

leng

th [

m]

Influences of spindle speed and feed speed on tool life cutting length

Milling of Inconel 718 by Takeoka

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Ad

Ad：軸方向切込み量Rd：径方向切込み量

Ad : 0.30 mmRd : 0.50 mmFz: 0.15mm/tooth

Tool diameter 6 mm

Relationship between cutting speed and cutting length

> When finishing, long cutting distance (feed distance) was achieved.> Tool: Ball end mill, TiAlN coated carbide,

2 mm in diameter

Turning of Inconel 718 with whisker reinforced ｃｅｒａmic

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300 360 420 480 540 600 660 720 7800

500

1000

1500

Cutting speed [m/min]

Tool

life

leng

th [m

]

Cutting conditions: SiC whisker reinforced alumina, depth of cut 0.3 mm, feed rate 0.1 mm/rev, wet

Ball end milling of Ti-4Al-4V

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Cutting conditions: cemented carbide ball end mill with nose radius of 1 mm, ap = 0.5 mm, ae = 0.5 mm, feed rate 0.02 mm/tooth

30 60 90 120 150 180 210 240

0.02

0.04

0.06

0.08

0.10

0Cutting speed [m/min]

Wid

th o

f wea

r V

Bm

ax [m

m]

Cutting conditions: Coated flat end mill, ap = 1mm, ae = 1mm, fz = 0.03 mm/tooth

Maximum width of flank wear against cutting speed

Maximum width of flank wear against tool rotation (by Anzai)

> When finishing small parts such as implants, watch parts, with small depths of cut,cutting speed should be increased.





> Summary

Overview

36

Effects of high pressure coolant (HPC)

37

Cleaning of machined surface & tool face

Deburring

+

High pressure coolant at a glanceKennametal BeyondBLAST

- Extended tool life- More effective for higher cutting speed- Small nozzle for increasing coolant pressure

Inserts with coolant channel

http://www.triconmetals.com/images/repositories/PDFs/JA_A-10-02469JA_Innovations2012.pdf

Coolant pressure：7 MPa（1000 psi）

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Coolant pressure：0.7 MPa（100 psi）

Classification of chip shape (INFOS)

Classification into 11 shapes.Needle chip (type 11) is added to 10 types in the right figure.

K. Nakayama: J.JSPE, 42, (1976) pp. 74-80. 39

bad

goodpermissible

(Ribbon chip)

(Tangled chip)

(Flat spiral chip)

(Spiral chip)

(Long tubular spiral chip)

(Short tubular spiral chip)

(Coiler spiral chip)

(Coil chip)

(Short coil chip)

(Shredded chip)

Relationship between chip type number and coolant pressureTitanium alloyNickel base superalloyStainless steel

breaking) (3) High pressure coolant (chip

40T. Obikawa, et al., Seisan Kenkyu，(2015)

Video:- Hole diameter： 6 mm- L/D: 72- Large wedge angle- Feed speed: 637 mm/min

Effects of high pressure coolant- High speed drilling- Pecking is not needed- High L/D ratio

http://www.youtube.com/watch?v=0Byx0F-yXgc&feature=youtu.be

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High pressure coolant (drilling)

L/D ratio: length to diameter ratio of a hole

Cost effectiveness- largest for drilling

Cost effectiveness of high pressure coolant

42

Cost reduction depends directly on the machining operation. > I.M.: Milling with end mill with inserts> E.M.: Milling with solid end mill> Drill: Drilling

- Work： Ti-6Al-4V - Pressure of HPC: 7MPa- Pecking during drilling is

not used for HPCused for low pressure coolant

M. J. Bermingham, 2014, Int. J. Adv. Manuf. Tech., 72, pp. 77–88.

New tool holder for high pressure coolant

Jet-tech method Jet-tech holder

43

L shape nozzle

Tool flank

Tool life

44

SUS304 Inconel 718

Tool wear evolution

Cutting conditions: cutting speed 300 m/mindepth of cut 1.0 mm, feed rate 0..2 mm/rev

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Cutting conditions: cutting speed 150 m/mindepth of cut 0.3 mm, feed rate 0.1 mm/rev





> Recent hot topics of machining in JapanGear skiving for dramatic reduction in gear cutting time

> Summary

Summary

45

Thank you

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Documents

Machni ni g Technool gy of r Aerospace and Auto Parts ... Technology for Aerosp… · Professor, Manufacturing Research Center, Tokyo Denki University. Emeritus Professor, The University