© 2014

Diamond blades - exceptionally wear resistant and extremely sharp

P. Gluche1, S. Strobel1, H.-J. Fecht2

1GFD Gesellschaft für Diamantprodukte mbH, Lise-Meitner-Str. 13, 89081 Ulm, Germany 2University of Ulm, Institute of Micro and Nanomaterials, Albert-Einstein-Allee 47, 89081 Ulm, Germany

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Content

• Introducing GFD • Why diamond? • Diamond fabrication • Plasma sharpening • Applications • Summary

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Short introduction of GFD

• Founded by Dr. André Flöter and Dr. Peter Gluche March 1999 in Ulm, as a spin-off of the University of Ulm and the Daimler research center

• Headquarter und production at Science Park II, Ulm, Germany

• 9 employees (May 2014)

• 2001 Introduction of Diamaze Scalpels

• 2003 Introduction of Diamaze PSD-blades

• 2004 Introduction of Diamaze Microparts

• 2010 Introduction of Diamaze PSD-tools

• 2008 Establishment of Diamaze Microtechnology SA, Switzerland

• 2010 Start of large scale production of microparts

• 2013 Establishment of Diamaze Coating Technology GmbH, Ulm, Germany

GFD headquarter in Ulm, Germany

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GFD‘s activities

Microparts PSD-Blades PSD-Tools R&D

Diamond spheres

• Watch industry • Converting industry • Packaging industry

• Metrology

Microtechnology SA

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Why diamond?

Diamond offers outstanding properties

• Highest mechanical strength of all materials • Lightweight material • Low coefficient of friction • Highly wear resistant • Chemically inert • Optical transparent from infrared to deep ultra violet • Valuable material for customers • ...

Diamond is extreme...

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• non-magnetic • chemically inert • very low coefficient of friction (diamond vs. diamond 0.2>cf>0.015)

+

Property Diamond Si Steel Ti

Youngs modulus Em (GPa) 700-1143 110-190 190-250 115

Fracture strength σB (GPa) 2-10,3 0,3-1,4 0,4-1,1 -

Indentation Hardness HiT (GPa) 68-105 11-13 - 2-3

Density (g/cm3) 3,515 2,321 6-8 4,5

weight

mechanical stability

wear, lifetime

Diamond is an ideal material for mechanical applications

Why diamond?

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Diamond

100 % carbon strong bonds (sp3) crystalline

Graphite

100 % carbon weak bonds (sp2)

DLC Diamond like carbon

Challenge: Transformation of weak-bound – into strong-bound carbon

100 % carbon sp2/sp3 – bound carbon amorphous

Terminology

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Diamond fabrication

Diamond

nature

Belt apparatus

Wedlake, In The Properties of Diamond (ed. J. Field) Academic Press, London, 1979

HPHT CVD

Single crystals

Single crystals Diamond powder

Single crystals Microcrystalline diamond films Nanocrystalline diamond films

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• Large scale CVD reactor for diamond coating • Coating surface approx. 0.5 m2/run • Energy consumption: approx.130 kW • Weight: approx. 4 t • Operating temperature: approx. 2200 °C • Operating pressure : approx. 1 mbar

Diamond fabrication

• Methane (CH4) acts as carbon source • The carbon is dissociated and condenses as

sp3- (diamond) and sp2 (graphite) hybridized-carbon at a substrate surface

• sp2 hybridized carbon is removed by reaction with atomic hydrogen to CHx radicals and returns into the gas phase.

• In contrast to DLC no ion bombardment is necessary.

• Steel cannot be coated (temp. too high) • Suitable substrates:

- Cemented carbides (low cobalt content) - Ceramics (Si-based) - Silicon

CVD allows to produce synthetic diamond without graphitic phases

Chemical Vapor Deposition (CVD) of diamond

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E. Butler Naval Research Laboratory

statistically oriented

excellent mechanical properties very low surface roughness

statistically oriented <100> textured

20µm

20µm

Heteroepitaxy <100> textured

Nanocrystalline diamond CVD Diamond

1 µm

CVD Diamond films

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Plasma sharpened diamond blade Cemented carbide substrate blade Diamond coated cemented carbide bade

cemented carbide blade diamond coating

Principle of plasma sharpening

Plasma sharpening

High residual wear volume at the cutting edge, high sharpness (small rc)

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Example: Blade with 20° blade angle

Blade cross sections

as coated technical sharpness

razor blade sharpnss

Plasma sharpening

rc < 0.2 µm rc < 0.05 µm

Sharpness can be adjusted to the application

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Special case: Razor blade for shaving (rc < 20nm)

16°

45°

radius of curvature < 20 nm

Scanning electron microscope (cross section)

Diamond

Cemented carbide

Adjustment of radius of curvature and micro geometry is possible

Plasma sharpening

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Execution: Computer controlled measurement system The blade cuts a polymer string which is fixed at one side and biased at

constant force on the other side. The force vs. displacement curve is captured. The maximum force reading is a value that indicates the sharpness of a blade

String Cutting Test

Quantifying the sharpness

Goal: Determination of the cutting force required to cut a defined string of polymer

blade

biased polymer string

computer controlled displacement

force gauge

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Principle and measurement results

String cutting test

Top view

Side view blade

string

string

maximum force reading Fmax

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Cutting force vs. polishing time • 15° blade angle

Plasma sharpening

Adjustment of cutting force (sharpness) possible Requirement: minimum sharpness that still yields a good cutting quality

800

900

1000

1100

1200

1300

1400

1500

1600

6 7 8 9 10 11

process time in abr. units

cutti

ng fo

rce

in m

N

.

15°

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Blade Max. cutting force in mN

Kitchen knife approx.2000

Industrial steel blade 469

Industrial WC blade 446

Diamaze PSD blade (normal sharpness) 472

Industrial steel blade with TiN 178

Diamaze PSD blade (extra sharp) 150

Ceramic blade (best blade ever seen 20°) 126

3 whole razor blade (standard) 51

3 whole razor blade (best) 46

Razor blade from cartrige 38

Diamaze PSD razor blade 16

Indu

stria

l bla

des

Raz

or b

lade

s

shar

per

Cutting force measurements (string cutting test) of state of the art blades

Quantifying the “sharpness”

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Schneidkräfte in Abhängigkeit von der Anzahl der Testzyklen

0

0,5

1

1,5

2

2,5

0 200 400 600 800 1000 1200 1400 1600 1800

Anzahl der Testzyklen

Schn

eidk

raft

(N)

Stahl-RasierklingeDiamaze-PSD G08

Cutting performance • Test of sharpness and durability (Diamaze G08 vs. Steel) • Test performed externally by Catra, Sheffield UK • Modern steel razor blades have a lifetime of approx. 400 test cycles

Cutting force limits

maximum force readings

Wear propagation

Number of cutting cycles

cutti

ng fo

rce

(N)

Critical user

Economical User

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Wear analysis • SEM analysis before and after cutting test at CATRA

new blade after 1600 cycles

Wear propagation

very low wear propagation

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• Product examples: technical cutting blades • Blade thickness 0.2 mm – 0.6 mm • Lifetime increase approx.:

• 20-60 x in contrast to cemented carbide or ceramic blades • 800-1000 x in contrast to uncoated steel blades

Plotter blades for • latex, paraffin • textiles, • plastic foils, • fiberglass cloth • carbon fiber cloth • rubber • paper, cardboard

Slotting blades for • plastic foils • metal foils • ultra-thin foils

Applications

Highest cutting quality and lifetime

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Extension of lifetime • Comparison of Diamaze PSD blades and ceramic blades • Material: plastic foil containing pigments (Titaniumoxides) • Number of test blades: 150 total

Life

tim

e

0

5

10

15

20

25

30

35

40

tungsten carbide ceramic Diamaze-PSD

1,5

36

2

Applications

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Application: Circular blade for glass cutting Cutting forces could be reduced by more than 50%

Diamaze PSD circular knife

uncoated TC circular knife

dislocation

norm

aliz

ed fo

rce

Applications

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0

10

20

30

40

50

60

70

tungsten carbide Diamaze-PSD

Extension of lifetime

• Comparison of Diamaze PSD blades and TC blades • Material: glass

1

63

Life

tim

e

Applications

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Comparison of total cutting costs of different blade types

Costs

13’720 €

2’767 €

778 € 640 € 205 €

Assumptions: Lifetime steel/steel coated/solid carbide/ solid ceramic/ Diamaze PSD=1/5/30/40/800 Time for blade exchange: 1min Machine down time for blade exchange: 3min Labor costs per hour: 30 EUR Machine costs per hour: 230 EUR Uptime Machine: 330 d.p.y Yield loss: not taken into account

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Conclusion

Thick hard-coating (diamond) Post treatment (plasma sharpening)

Adjustable sharpness (20 µm <rc< 20 nm) and micro geometry Cutting ability adjustable High wear volume (6-10 µm)

Extraordinary lifetime increase (up to 800-1000 x in contrast to steel) Extraordinary edge holding property (very low wear propagation)

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Time is over – Thank you

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Contact: Dr. Peter Gluche

GFD Gesellschaft für Diamantprodukte mbH Lise-Meitner-Str. 13

89081 Ulm, Germany Tel. +49 731 880 334 0 Fax +49 731 880 334 10

Email info@gfd-diamond.com www.diamaze.com