alternative and new ways of production for gear manufacturing · • electrical discharge machining...

Alternative and new ways of production for gear manufacturing

Prof. Dr. Ir. Bert LAUWERSDean | Faculty of Engineering TechnologyDepartement Mechanical Engineering | Research Group “Advanced Manufacturing Processes” [email protected]

EUROTRANS Gear Training on ‘Production’25 February – 1 March | 2019

mailto:[email protected]

2

• Full Professor KU Leuven• Dean | Faculty of Engineering Technology• Research & Education

• Advanced Manufacturing Processes(Department Mechanical Engineering)

• Cooperations• Member FlandersMake• Sirris

Who I am ?

Research Group “Advanced Manufacturing Processes”Department of Mechanical Engineering

2Research Group “Advanced Manufacturing”

Department of Mechanical Engineering Faculty of Engineering Technology

3

• Research• Process• Digital Manufacturing

(Control & CAD/CAM)

Manufacturing Processes @ KU Leuven


Manufacturing Processes

Additive Manufacturing

(AM)

Subtractive & Hybrid

Processes

Micro & Precision

Flexible Sheet Manufacturing

Lifecycle Engineering

Metrology & Quality Control

4

• Subtractive & Hybrid Processes

• Processes: Multi-axis machining, EDM, ECM, Hybrid Processes,..

• Materials:Advanced alloys, carbides, ceramics

• Digital ManufacturingAdvanced Tool path generation, Process Planning,..

My research


Machining of (complex shaped) components in either soft or hard

materials

5

• Common technologies for gear manufacturing• Other technologies

• Electrical Discharge Machining (EDM)• Multi-axis machining• Additive Manufacturing technologies• Combinations

• Commercial systems | Solutions• Process chains for fast (low series) gear manufacturing

• One day production of single gears

• Gear manufacturing in advanced materials (e.g.Ceramics)

• Technologies for micro gear manufacturing

Course content


Principles & TechnologyTest case

Common technologies for gear manufacturing

6Research Group “Advanced Manufacturing Processes”

Department of Mechanical Engineering

7

Common technologies


8

Generative methods


• Hobbing• Shaping

9

Non-generative methods


• Broaching• Milling

10

Stamping,..


• Forging• Stamping• Casting• Powder

MetallurgyTechniques

• InjectionMoulding

11

Finishing


• Shaving• Grinding• Honing

12

• New production methods for functional gear prototypes and small series production

• Machine tool manufacturers and CAD/CAM software providers moving towards new and flexible solutions forgear manufacturing

Trends…


Other technologies



14

• Objectives/requirements• Resulting shape accuracy should be comparable to

conventional series production processes• Surface roughness within required specifications• Same or better surface/material integrity (stresses,

hardness,…)• Increasing productivity & flexibility

• Omit the need for dedicated tools• Flexible setup (easy to adopt to different gear designs)• …

Application of other technologies…


15

• Electrical Discharge Machining• (Multi-axis) Milling• Additive Manufacturing

• Research carried out in the frame of various projects, supported by VLAIO

• “Precision Manufacturing for new and better products”

• ‘INTLAS’ Integrated Laser Hardening

Technologies discussed…


16

Electrical Discharge Machining (EDM)


servo feedcontrol

generator

fluiddielectric

tool

workpiece

+

-

gape-

ions

dielectric

moltenmaterial

moltenmaterial 1. Ingnition phase

2. Melting phase3. Implosion

17

EDM – configurations


Sinking EDM Milling EDM Wire EDM

18

• (+)• Machining of hard materials

• High alloyed steels, ceramics,…• High dimensional tolerances • Surface roughness values (< 0,5µm Ra)

• (-)• Process speed• HAZ

EDM – process characteristics


19

• Wire EDM• Wire ∅: 50…300µm

EDM & gear manufacturing


20

• Die sinking EDM• Machines are fully NC-controlled• 4-axis• Special strategies for gear manufacturing



21

• EDM milling• Use of standard tubular electrodes

• Similarity with milling operations



22

• Material removal by moving milling cutters

• Tool geometries• Ball nose cutters• End mill cutters• ….

NC-milling


23

• Strategies• Contouring

• 3-axis / multi-axis• Using flank of cutter

• Cavity milling• 2D/2,5D• Tools

• End mills (OK)• Ball nose ( step-over !!!!)

NC-milling


24

• Strategies• Machining of complex shapes | cavities

• Pre-machining by cavity machining• Finishing

• Using ball nose cutters• 3-axis• Multi-axis

• Using end-mill cutters• Multi-axis !!!!

NC-milling


v

u

25

• Various methods (SLM, FDM, cladding,…)• Various materials (plastics, metals,..)

• Selective Laser Melting most potential

Additive Manufacturing


Slicing Layer by layer

26

• (+)• ‘High’ accuracy (among the AM

methods !!!!)• Various materials available &

technologies developed• Dense products• Simple & easy programming

• (-) • Slow building process• Residual (thermal) stresses

Selective Laser Melting


27

• Mold inserts with cooling channels

• Built-in heat exchanger

• Medical

• Gears ?

SLM - Applications


28

CAD/CAM & machine programming


Process planning

NC-postprocessor

NC-program(ISO-code)

CL-Data

CAD

CAM

IGES, STEP, STL

CAM (AM)Slicing & scanning

Other technologiesTest case - Comparison



30

Test Case


Test case gear dataMaterial 16MnCr5Number of teeth (Z) 36Heigth 31.5 [mm]Normal module (mn) 2.120 [mm]Reference circle diameter (d0) 76.320 [mm]Base circle diameter (db) 72.985 [mm]Crowning width of tooth (cβ) 0.008 +/- 0.003 [mm]Gear quality Acc. To DIN 3960DIN Class 6Surface finish (Ra) 0.8 [µm]Profile angle variation fHα 6 [µm]Profile form variation ff 8 [µm]Total profile variation Ff 10 [µm]Tooth trace angle variation fHβ 12 [µm]Total tooth thrace variation Fβ 15 [µm]Tooth trace form variation Fβf 9 [µm]Run out Fr 24 [µm]Cumulative pitch error Fp 32 [µm]Single pitch error fp 7 [µm]Pitch to pitch error fu 9 [µm]

31

Gear Quality parameters


Source: Wenzel

32

Wire EDM – set-up


Wire EDM

33

Wire EDM – Machining procedure


(A)

(D)

(C)

(B)

(A) Machined holder

(B) Gear Blank gluedon holder

(C)Gear machinedexcept few toothtips

(D)Gear removed fromholder, rotated 10°, glued back forremovingremaining tips

34

• Setup• Sodick AQ 537L wire-EDM• Water based dielectric• 1 Main cut and 4 trim cuts• Ø 0.25 mm brass wire

• Surface roughness• Main cut: 3 µm Ra• Final trim cut: 0.42 µm Ra

Wire EDM - results


Klink, A., Guo, Y.B., Klocke, F., 2012, “Surface integrity evolution of powder metallurgicaltool steel by main cut and finishing trim cuts in wire- EDM”, 1st CIRP Conf. On Surface Integrity (CSI)

35

Wire EDM - results


Task Time [min]CAM programming 90Manufacturing of the tool holder 200Positioning and gluing 15Main cut 400Trim cut 530Repositioning and gluing 15Removing of the remaining tips 70Total machining time 1320

Gear quality parameter Measured value [µm]

Limit [µm]

Surface finish (Ra) 0.4 0.8Profile angle variation fHα 0.6 6Profile form variation ff 1.9 8Total profile variation Ff 2.3 10Tooth trace angle variation fHβ -31.9 12Total tooth trace variation Fβ 31.6 15Tooth trace form variation Fβf 0.5 9Run out Fr 9.4 24Cumulative pitch error Fp 6.8 32Single pitch error fp 3.5 7Pitch to pitch error fu 5.9 9

• Trace angle variation out of tolerance wobble• Excellent gear quality, however limited flexibility (ruled surfaces)

36

Wire EDM - possibilities


Tip Relief

Root Relief

Angular Profile Variance

Profile Crowning

• Possible: • Tip relief, root relief, angular profile variance, profile crowning

37

Wire EDM - possibilities


• Might be possible (further research required):

• angular lead variance, end relief

• Not possible: lead crowning, helical gears

Helical Gear Angular Lead Variance

Lead CrowningEnd Relief

38

Multi-axis milling (4-axis)


39

Multi-axis milling (4-axis)


1) Contour 12 mm end mill 2) Profile 3 mm end mill8000 rpm, 280 mm/min

3) Profile 2 mm end mill12000 rpm, 320 mm/min

4) Profile 2 mm ball mill16000 rpm, 640 mm/min

40

• Surface roughness

• Tooth trace angle variation fHβ = 59.5 µm Ensured good parallelism of XY plane machine and gear blank fHβ = 4.1µm

Multi-axis milling - results


No. of passes 150 250 400 450 500 550Surface roughness Ra [µm] 0.76 0.38 0.27 0.21 0.24 0.22Required roughness Ra [µm] 0.8

41

• Flank quality – influence of milling strategy



Right flank quality <<left flank quality

( )

Pull

Left Right RightLeft

( )

PushPull Pull

42

• Quality - Repetitive pitch error• Individual pitch error in the order of a few microns, which add up

!!!!

• Possible reasons ?• Stiffness of the machine tool set-up ?

• Influence tool holder• Stiffness of the clamping set-up

• CAD NC errors ?• Temperature stability ?• Sequence of operations ?• …..



40 µm

43

• Quality - Repetitive pitch error• Influence of the tool holder

• Before

• New tool holder system • Tool length with less overhang, shrink holder



40 µm

20 µm

44

• Quality - Repetitive pitch error • Stifness clamping ?



Radialdisplacement

in µm at R=100mm

Rotational force/moment in Nm

10 20 30 40 50 60 70

Cla

mpi

ngfo

rce

in N

m 20 2 8 55 140 180 180 18030 3 5 13 40 135 170 14540 2 3 6 8 28 65 15050 3 4 4 5 7 55 10560 2 2 3 3 10 33 75

45

• Quality - Repetitive pitch error • CAD NC link ?

• Tolerances introduced (file generation, Intol/outtol for tool pathgeneration,…)

• Loss of accuracy ?



NATIVE Pro-E STEP Siemens NX Heidenhain

CAD CAD CAM Control

46

• Quality - Repetitive pitch error• Temperature stability?



Time (min.)

Dis

plac

emen

t (µm

)

47

• Quality - Repetitive pitch error• Sequence of operations



1 3 5 79

1113

15171921

2325

2729

313335363432302826

2422

2018161412

108 6 4 21 36 3534

3332

3130292827

2625

2423

222120191817161514

1312

1110987

65 4 3 2

48



Task Time [min]CAM programming & toolpath generation 90Clamping and alignment workpiece 15Roughing 3 mm endmill 60Roughing 2 mm endmill 90Finishing 2 mm ball mill 600Total manufacturing time 855

Gear quality parameter Measured value [µm] Limit [µm]Surface finish (Ra) 0.2 0.8Profile angle variation fHα -4.7 6Profile form variation ff 3.3 8Total profile variation Ff 8.0 10Tooth trace angle variation fHβ 4.1 12Total tooth trace variation Fβ 14.1 15Tooth trace form variation Fβf 2.1 9Run out Fr 16.8 24Cumulative pitch error Fp 18.5 32Single pitch error fp 8.5 7Pitch to pitch error fu 4.0 9

49

• Quality - Single pitch error• Control of tool wear ?• Non-optimal conditions for 3-axis milling with ball nose cutters

• Chaniging process paramters (eg. cutting speed)• Effect on tool wear !!


Research Group “Advanced Manufacturing Processes”Department of Mechanical Engineering 49

50

• Quality• Alternative milling strategies

use of end-mills constant contact point (& cutting speed) tool axis perpendicular on surface normal in contact point



51

• Program structure

Overall milling strategy


• Tool call• Measuring tool diameter in tool contact point (Blum laser)• Logging tool diameter/tool length• Milling flank right (actual tool diameter)• Milling flank left (actual tool diameter)• Rotation of C-as (delta 10°)• Measuring tool diameter in tool contact point (Blum laser)• Logging tool diameter/tool length• Milling flank right (actual tool diameter)• Milling flank left (actual tool diameter)• Rotation of C-as (delta 10°)• …

52

• 16MnCr5 • No standard SLM material• But possible [cfr. reserach Kempen et. al]

• However pay special attention to prohibit cracks for carbon richsteels

• Procedure • CAD file preparation (slicing)• SLM process• Postmachining steps

• Wire EDM operation to remove part from base plate• Shot peening to create compressive residual stress

Selective Laser Melting


53

Selective Laser Melting - Results


Gear quality parameter Measured value [µm]

Limit [µm]

Surface finish (Ra) 2.5 0.8Profile angle variation fHα -58.7 6Profile form variation ff 32.8 8Total profile variation Ff 75.2 10Tooth trace angle variation fHβ -49.9 12Total tooth trace variation Fβ 43.2 15Tooth trace form variation Fβf 19.3 9Run out Fr 111 24Cumulative pitch error Fp 133 32Single pitch error fp 29.0 7Pitch to pitch error fu 34.7 9

TaskTime [min]

CAD file preparation (slicing) 30SLM process 840Postmachining 150Total machining time 1020

54

• Wire-EDM• Superior accuracy and good surface quality, “low” flexibility

• SLM• Low surface finish and shape accuracy• Possible as Near Net Shape strategy !

• Multi-axis milling• Accuracy OK: some issues are dealt with, still some

improvement needed• High flexibility (flank corrections, helical gears, double

helical gears,…)

Comparison between various methods


Machining Technology Machining time [min.] Surface finish Ra [µm] Shape accuracy FlexilbilityMilling ++ ++ + ++Wire-EDM - + ++ -Selective Laser Melting + -- -- ++

Commercial Systems



56

Defawes / Bierens developed a gear milling strategy/software

• Non-CAD model based, but mathematical description based • Only available as service, software/strategy not for sale• Any gear shape possible, for example: own developed S-

shaped gear• 30-35% claimed increase of power transfer• Less heat and noise• No need for axial fixation

Defawes / Bierens


57

Euklid provides software for toolpathplanning for gear milling

• CAD model based• Special module for gear toolpath

planning

EUKLID Gear CAM


58

DMG GearMILL is software for toolpath planning for gearmilling by ball end mills

• Only available for DMG machines• Not a lot of non-commercial documentation to be found

DMG GearMILL


59

• Software & hardware

• InvoMilling tooling strategy• (+)

• Faster than using end milling strategies• Fast programming using the

accompanying software• (-)

• Less flexible compared to end milling strategies

• Limited quality (up to DIN6)

Sandvik / DMG InvoMilling


Process chains for fast (low series) gear

manufacturing



61

• Dedicated tools are required for gear production (gearhobbing & grinding)

• 8 weeks lead time, order of dedicated tools

Conventional production


62

• Process chain based on turning/milling still quite some logistics

• Conventional hardening strategies:• Carburising• Carbonitriding• Nitriding• ... All require taking out the workpiece, logistics to hardening facility, re-clamping and re-alignment, hard finishing.

Process chain


Turning / MillingUnclamping + to hardening

setupHardening

re-clamping and re-

alignmentHard finishing

of part

63

• Performing the hardening operation on the machining center

• Possible hardening strategies:• Flame Hardening:

• Less control of hardening, flat surface hardening possible, not veryflexible

• Induction Hardening• Good control of process, not very flexible (electrode is workpiece

shape dependant)• Laser Hardening

• Good control of process, very flexible, very localized heat input

Use of hybrid machine platforms..


Turning / MillingHardening on

machining center

Hard finishing of part

64

• Principle• Laser heats up the material up to above the Ac3 temperature.

Material is cooled quickly below Ms temperature.• Higher hardness values possible (faster cooling)

(Selective) Laser hardening


65

• Tailored hardening possible• Bearing locations on shaft• Active flank of gear teeth• Cutting edge of knife blade• …

• Limited distortions• Localized heat input• Hard finishing operations in a lot of

applications not longer required



66

• Technology is certainly not new !• Already implemented for example within robot manipulators




manufacturing

Multi-axis platform for gear manufacturing (with laser integrated hardening)



68

• Integrate hardening operation within in machiningcenter

• Reduce logistics• No unclamping/re-clamping• No re-alignment waste of time and alignment errors• Reduce total lead time

• Integration of Laser• 500W Nd:Yag laser• Laser head developed

@ KU Leuven basedon HSK-63 holder

Objective


69

In operation….


70

Laser head (detail)


71

• Adapt conventional milling machine to laser operation• Replaced all transparent panels, added safety glass and IP

camera• Added seperate sealable storage unit with automatic tool

changer for storing laser head during milling operation

Implementation on multi-axis platform


72

• Control system• Allow control of laser by NC-code on 5-axis milling machine• Control storage unit, laser-head tool change• Control power output, feedback from pyrometer

Implementation on multi-axis platform


73

• Material:• C45 steel (1.0503, EN 10277-2)• Hardness 200 HV

Technology development | results


74

• Variable parameters: • Spotsize diameter (D) [µm] • Traverse speed (v) [mm/min]



75

• Measured values• Depth of hardening

Vickers micro hardness tests

• Maximum hardnessVickers micro hardness test, average of 2 measurements closest to the surface

• Average measured temperature2 color pyrometer, 50 Hz, averaged in time

• Melted or not Surface roughness comparison before/after laser treatment, every track measured 3 times before and 3 times after hardening. 2-sample t-test, 95% confidence limit



76

• Depth of hardening



• Depth of hardening – influenced by spotsize and traverse speed, combined factor not significant

• Lower traverse speed and smaller spotsize have a positive effect on the depth of hardened layer

77

• Maximum hardness



• Maximum hardness – significantly influenced by spotsize, traverse speed and combined factor

• Smaller spotsize and slower traverse speed have positive influence on maximum hardness

• Combination of large spotsize and fast traverse speed results in dramatically reduction of hardness

78

• Melted or not



• Melted or not – both spotsize, traverse speed and combined factor are significant

• Only melted when spotsize diameter was small and the traverse speed is low

79

• Thermal model• Transient heat transfer model (ABAQUS), 3D thermal solid

elements with 8 nodes• Temperature dependent thermal properties of C45 were used



80

• Thermal model• 100 mm/min 877°C isotherm

(dashed line) has approximate same size of hardened zone

• A: 1910 µm simulated vs 1885 µm measured

• B: 229 µm simulated vs 210 µm measured

• 400 mm/min max. temperature < 877°C

• Simulated: temperature below ‘critical’ temperature

• Measured: no hardened zone



81

• Multi-axis milling machine converted to machining center capable of laser hardening

• Full factorial design involving two variable parameters was conducted as a proof of concept

• It can be concluded it is well possible to harden C45 steel from 200HV up to 750HV, on a fully functional 5-axis machining center.

• A transient heat transfer model was successfully applied to simulate the temperature distribution during the hardening process

Integrated laser hardening Conclusion


82

• Injection molding nozzle made out of Uddeholm Unimax• Conventionally hardened up to 52 HRC (540 HV)

Case study: Injection moulding nozzle


83

• Hardening strategy tested on thermal model• Hardness values exceeding 840 HV100 (64 HRC) (>52

HRC conventional hardening)• It takes about 7 seconds to harden 1 nozzle!

Case study: Injection moulding nozzle


84

• Multiple tracks…. (is required for flank hardening of gears)

• Uniform area hardening? • Softening effect !



85

• New setup: Scanning hardening on Mori Seiki NTX2000• High speed scanning motion + slow feed

scanning between 50 and 150 Hz

Scanned Laser Hardening


86

• Mechanical & Optical design



FIBER

87

Set-up


88

• Development of optimal scanning strategies• High speed scanning motion + slow feed

scanning between 50 and 150 Hz



Sinus scanning overheatingat edges

20 mm

89

• Sinusoidal scanning motion• Test on ‘laser’-paper

• Low power (20 W), 50 Hz, 1 second (no feed) overheating at the edgesas expected

• Same effect visible on C45 steel (500W, 50 Hz, 100 mm/min feed)

• Optimized scanning function



90

• Optimized scanning function • Mirror dynamics issue: optimized function

requires to high accelerations

• Frequency limited to 50 Hz and standard triangular shaped motion

• Still melt at edges !



91

• 18 mm heat affected zone• Depth of hardened zone:

• 0.2 mm, heat affected zone: 0.3 mm

• Melt at edges

Experimental results


C45 steel (0,46% C, <0.4% Si, 0.65 Mn, <0.4% Cr)

92

Experimental results


93

• Optimized scanning function • Triangular• + Power compensation for reduction of overheating



94

• Programming strategy: CAM + scanning software• Maintain conventional toolpath planning by CAD/CAM for

industrial applicability

Programming ?


95

• Developed CAM functionality• Machine movement: straight line• Mirror scanning width: depends on machine position

Programming ?


Toolpath 1: Machine toolpath Toolpath 2: Scanning contour

96

• Developed CAM functionality• Machine movement: straight line• Mirror scanning width: depends on machine position

Programming ?


lowered frequency (for illustration)

97

Programming for gears


Pyrometer

98

The hardening process


99

• Temp. setpoint 1300°C, feedrate of 150 mm/min

• Hardness between 600 to 800 HV along gear flank

• Except in “undercut region” hardness 220 HV

• Further improvement• Change inclination angle

Hardening results


100 Research Group “Advanced Manufacturing Processes”Department of Mechanical Engineering


manufacturing

Gear manufacturing in advanced materials



102

• Technical ceramics: • Hardness!• Toughness?• Harsh environments!

Ceramics !


Density [g/cm3]

Hardness HV10 [kg/mm2]

Toughness[Mpa/m1/2] E-modulus [Gpa] EDM-able?

1020 steel 7.87 115 200 yesAL2O3 3.94 1905 4 390 noZrO2-Y 6.00 1200 9 210 noB4C 2.51 2800 3.1 440 yesSiC 3.10 2600 4.6 410 yesSi3N4 3.20 1600 7.5 370 noAlN 3.30 1100 3 331 no

Composites

Zr02-TiN 5.8 1350 9.7 280 yesSi3N4-TiN 3.97 1508 8.7 333 yesAl302-TiCN 4.41 2073 2.66 386 yes

103

• Injection molding (followed by sintering)• Series production• Low dimensional accuracy!

Gear manufacturing - ceramics


104

• Green machining• Easy to machine• Has to be sintered afterwards low dimensional accuracy

(shrinkage)



105

• Machining in sintered state• High dimensional accuracy possible (no more shrinkage)• Very high hardness difficult to machine using conventional

techniques



UAG

ELID-Grinding

Die sinking EDM

Micro-EDM

Milling

106

• Current• Injection molded Yttria stabilized

zirconia

• Other technologies for low series ?• Wire EDM ?• Zr02-TiN (material developed @ KU

Leuven) machined by

Case study – gears for planetary box


107

• Zr02-TiN machined by Wire-EDM fail at 115 Nm static load ↔Y-Zr02 (injection molded) fails at 90 Nm

• After applying maximum load (8000 rpm input, 30 Nm output load, 40 rpm output) for 160h, no wear on ceramic gears

• In the experiment, gear box failed after 1450h under maximum load by a broken tooth

• High wear on planetary gear made of hardened steel (16MnCr5)

Results (loading)


Manufacturing of micro gears



109

• Injection moulding• EDM

• Example – micro gear made of ZrO2-TiN 60/40 • Ø1 mm gear machined by Micro-EDM

Similar technologies


Material E [GPa] Hv [kg/mm2] KIC, 10kg [MPam0.5] K [W/m°K] ρ [10-5Ωm]

Zr02-TiN 280 1350 9.7 6.41 2.94

110

• (Micro) milling EDM• “Milling”- like process• 0.5 mm standard tube as tool

which can be wedged to smaller diameters

Micro EDM of micro gears


tool

111

• Micro Gear mold• Depth: 0.9 mm• Tool:

• Ø 0,5 wedged to 0,26 mm for pocketing• Ø 0,5 wedged to 0,113 mm for contouring

• Machining time• 38 min. of erosion | 44 min. of wedging

Applications


200 µm

112

• Bouquet J., Hensgen L., Klink A., Jacobs T., Klocke F., Lauwers B., Fast production of gear prototypes – a comparison of technologies, 6th

CIRP international conference on high performance cutting, HPC 2014

• Bouquet J., Van Camp D., Vanhove H., Clijsters S., Amirahmad M., Lauwers B., Combining machining and hardening in one setup, applied on C45-steel, 8th International conference on photonic technologies, LANE 2014

• Malek O., Vleugels J., Perez Y., De Baets P., Liu J., Van Den Berghe S., Lauwers B., Electrical discharge machining of ZrO2 toughened WC composites, Proceedings of the 17th Plansee Seminar on High Performance Materials, Reutte, 2009

References


113

• VLAIO for various research projects, in cooperation with Sirris and FlandersMake

• Machine Tools Technologies Research Foundation (MTTRF) for providing the machining centre “Mori Seiki NTX2000” to KU Leuven to be used in various research and educational programs

• GF Agie Charmilles for providing various EDM equipment

• Siemens for providing CAD/CAM & NC-programming softwre

Acknowledgement


alternative and new ways of production for gear manufacturing · • electrical discharge machining...

Documents