Rapid Microtooling with laser based methods

Transcription

1 Hochschule Mittweida University of Applied Sciences Rapid Microtooling with laser based methods R. Ebert, U. Löschner, A. Streek, J. Schille, T. Süß, L. Hartwig, U. Klötzer, H. Exner ISL 2008 Chemnitz November 12 13, 2008

2 Contents 1. Project overview 2. Experimental setup 3. Laser machining results 4. Summary and perspective Robby Ebert 2

3 Project time: Aim: development of 5 new processes: Laser micro sintering 3D cutting of transparent materials Micro cladding 3D material removal with high repetition fs - laser Micro processing with 3 kw Singlemode-Fiberlaser Robby Ebert 3

4 The project cooperating firms: 3D-Micromac AG Chemnitz Acsys GmbH Mittweida IVS AG Chemnitz Laservorm GmbH Altmittweida MicroCeram GmbH Meißen Laserinstitut Mittelsachsen e.v. Mittweida Roth & Rau AG Hohenstein-Ernstthal DEMOS GmbH Dresden Jenoptik L.O.S. GmbH Jena LaserSign Mittweida Robby Ebert 4

5 Experimental Setup (built up by project group) Micro machining setup with fs - (250 fs) und ns - (6ns) laser sinter station structuring station Micro cladding setup with fiberlaser, scanner and robot High power micro machining setup with 3 kw Singlemode- Fiberlaser sinter station 2 structuring stations Robby Ebert 5

6 Micro machining setup Monitoring Power meter Mirror Mirror Attenuator Laser Technical data ns - laser fs - laser Stationary objective or Laserscanner wavelength max. power λ = 1064/532 nm P av = 34 W λ = 1030 nm P av = 15 W max. rep-rate f P = 30 khz f P = 25 MHz pulse length Focussing optics Positioning stage τ H = 6 ns τ H = 250 fs - scanner with f theta; f = 56 mm - stationary asphere; f = 15 mm I max = 450 GW/cm² I max = 8 TW/cm² Robby Ebert 6

7 Micro cladding setup Robby Ebert 7

8 High power micro machining setup Robby Ebert 8

9 Laser microsintering process Example: Reaction sintering of SiO Sintering of separate subunits Sinter reaction: SiO SiO 2 Robby Ebert 9

10 Laser microsintering of tungsten in vacuum p = 0.01 mbar p = 1 mbar p = 10 mbar p = 100 mbar p = 500 mbar REM images of the sintered body s surface, section width 50 µm to be published in Applied Physics Robby Ebert 10

11 Laser microsintering of molybdenum turbocharger turbocharger: (1) compressure section (2) air bearing (3) actuator section height: diameter: th = 250µm 18 mm 12 mm Ø 6mm design drawing: combined part consisting of housing and internal rotatable axle Function tested successfully Cross section shows porosities Robby Ebert 11

12 Laser microsintering with new regime 5mm 3mm Height: Diameter: 5mm 3mm 10mm Comparison between the old and the new regime Magnification of the specimen Robby Ebert 12

13 Laser microsintering with new regime 2mm 2mm Functional parts (drive line for a medical application) Single chain link and cross section d=2.5mm l=7mm published in proceedings of 19. SFF Symposium (2008, Austin) 2mm assembly of 4 chain links before and after polishing Robby Ebert 13

14 Generation of 3d glass parts as a new rapid tooling technology 3d laser cutting of glasses via laser induced micro defects using high intensity short nanosecond (ns-) and ultrashort femtosecond (fs-) laser pulses benefit: component has properties of bulk material compared to sintered parts How does it work? requirements on laser system intensities: > 10 9 W/cm² laser spot: TEM 00, diameter <50 µm pulse length: < several nanoseconds pulse energy:? Robby Ebert 14

15 Results of 3D cutting with ns pulses R a = 3.2 µm R max = 17.7 µm R a = 2.5 µm R max = 11.6 µm y [µm] 1000 y [µm] 1000 x [µm] x [µm] 0 0 λ = 532 nm f = 56 mm E = 260 µj 200 µm λ = 1064 nm f = 15 mm E = 200 µj 200 µm Robby Ebert 15

16 Result 3D cutting with ps pulses 1 mm R a = 8.3 µm R max = 41.7 µm 1000 y [µm] x [µm] published in proceedings of ICALEO 2008 (Temecula) f = 56 mm E = 3 µj τ H = 1.5 ps pd = 0.7 µm 200 µm Robby Ebert 16

17 3D parts made of BK7 glass Cylinder Sphere Pyramid 1 mm 1 mm 1 mm 1 mm 1 mm λ = 1064 nm f = 15 mm E = 250 µj Robby Ebert 17

18 Micro cladding min. line width 30µm min. elevation 5µm Robby Ebert 18

19 Ablation with high-repeating fs - laser ablation rate depending on repetition rate 2,0 10 ablation rate [mm 3 /min] 1,6 1,2 0,8 0,4 single pulse ablation threshold ablation rate pulse energy pulse energy [µj] 0, repetition rate [MHz] Robby Ebert 19

20 Ablation with high-repeating fs - laser 13µm 25µm 50µm published in proceedings of LPM 2008 (Quebec) Robby Ebert 20

21 Ablation with high-repeating fs - laser Groove structures, width 73.3µm, depth 21.6µm Robby Ebert 21

22 First result with high power singlemode fiber laser Ablation cutting of sheet metal (thickness 2mm) - Laser power 3 kw - Focus diameter 30µm - Scan speed 5 m/s passages - Gap as far as 10µm! - Ablation rate up to 50mm 3 /s Robby Ebert 22

23 First result with high power singlemode fiber laser High speed ablation of ceramics - Laser power 1,5 kw - Focus diameter 50µm - Intensity 7,6 *10 7 W/cm 2 - Scan speed 8 m/s - deep of groove is 32µm Robby Ebert 23

24 Summary and perspective sinter densities of 97% have been achieved with a new regime 3D micromachining of glasses with short ns-laser pulses and highly repetitive fs-laser pulses is possible micro cladding with scanner and fiberlaser allowing high resolution with high-repeating fs - laser high precision an high ablation rates achieved micro structuring with high power single mode fiber laser is possible Robby Ebert 24

25 Summary and perspective Setup: 3 kw Singlemode Fiberlaser Polygonscanner (10000 RPM) E/O Modulator Prospectus: Structuring power 100 cm 2 / s (Scan velocity 400m/s, line distance 25µm) Robby Ebert 25

26 Research supported in the course of Rapid Microtooling mit laserbasierten Verfahren (Innoprofile) funded by Bundesministerium für Bildung und Forschung (03IP506) THANK YOU FOR YOUR ATTENTION!! Robby Ebert 26