Process and Machine Technology for …...Outline • Micromachining Examples • Functional Surface Texturing • 3D Texturing Technology • Machine Technology and Control Software

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Process and Machine Technology for Micromachining

and Surface Texturing of Complex Products

Max Groenendijk

Company Introduction •  Spin-off company from University of Twente and

M2i Institute, founded in 2008, active in

•  Ultrashort Pulsed Laser Materials Processing

•  Offering:

–  Machines for Production and R&D

–  Process and Application Development

–  Job Shop Production

•  Specialist in Surface Texturing on 3D curved Surfaces

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Outline

•  Micromachining Examples

•  Functional Surface Texturing

•  3D Texturing Technology

•  Machine Technology and Control Software

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There are many applications for < 100 W lasers combined with galvo-scanner beam deflection Still a lot of development is needed towards exploiting the full potential of such applications High-precision, complex processes need better control (software)

Microdrilling

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•  Hole diameters down to 1 !m •  Control on shape: funnel, conical,

(nearly) cylindrical

Micromilling

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•  Direct write, software controlled geometries

•  Machining of all materials:

•  Hard: SiC, hardmetal etc.

•  Delicate: polymers, membranes, very thin...

•  2,5D profiling / 3D products

hard

met

al

Processing Efficiency

•  Micromilling of hardened steel •  Best efficiency around 1 J/cm2 peak fluence •  Only high reprates (here 6 – 8 MHz) can use full laser power •  High scanning speeds are needed

–  > good control on sky-writing is essential 6

Micromachining Alumina

•  Round pockets ø 12,5 mm

•  Depth 20 !m +/- 0.5 !m (+/- 2.5%)

•  Very sensitive material

•  1% variation of laser power results in ~ 10% variation in pocket depth

•  Inherent depth variations across a machined pocket are too large

•  Depth variations reproduce 7

On-the-fly correction •  Measure the depth variations •  Generate background map •  Adjust laser power on-the-fly during machining •  Significant reduction of inherent depth variations

What you need: •  Fast modulation of laser power •  Ability to implement this strategy in your control software

8 2 !m peak to valley 0,7 !m peak to valley error map

Functional Surfaces Textures

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Manipulation of light

From engine parts to skin comfort

Manipulation of cell adhesion

Wetting Properties

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m !

Partial wetting

High speed recording

Milk-ophobic Super hydrophobic and hydrophillic surface

Tribological Properties

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Three functions of dimples: 1.  Pressure build up 2.  Oil reservoir 3.  Wear Particle Trap

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What textures can we make with USP lasers?

LIPSS Regimes

1.  Nanospheres

2.  High spatial frequency LIPSS (parallel to laser polarization)

3.  LIPSS (perpendicular to laser polarization)

13 Source: M2i TULP project, Jozef Obona

Laser induced periodic surface structures

Nanostructures by LIPSS

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Cone like protrusions (CLP)

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Stochastic textures in steel: typical sizes and spatial frequency can be controlled by laser process

Microstructures

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Molded Textures

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(INJECTION) MOLDING

Micro- nano textured steel mold surface

Replication of micro- nano texture in injection

molded polymer

3D Texturing Machine

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3D Laser Micromachining and Texturing Machine Picosecond pulsed laser, 5 axes + galvo Scanner

Tiling of Surface

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Step and Scan Approach

Texture Generation

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Dimple patterns with a specific density are generated

3D texturing test

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Result

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Functional surface texture

Marked outlines of the tiles

Tiles visible due to the regular dimple packing

Texturing Mirror Cup Mould

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•  Demonstrator: Injection mold for car mirror cap

•  Goal: obtain a super-hydrophobic effect

FP7 project Nanoclean

Tiling - Meshing

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CAD generated STL surface description

Remeshed surface

Mold texturing

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Injection molded mirror cups

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FP7 Project APPOLO

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•  Development of technology for soft-touch surfaces in car interiors

•  Our pillar textured surfaces exhibit a ‘silky smooth touch’

•  Reduced friction due to largely reduced skin contact area

•  Optimization of machine and further development towards industrial use of technology

Machine Technology •  Goal: realize the full potential of ultrashort pulse

laser micromachining

•  Processes can get complex •  Processing strategies need to be well defined •  High degree of control on processing parameters

•  Users should concentrate on process, not on machine specific details (like scanner delays, manual calibrations and power measurements)

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•  Demands for high level of integration / automation •  Demands for advanced control software

Control Software •  Specifically designed for step-and-scan laser micromachining •  High level and machine independent programming •  Structured job definitions, written in general-purpose object-oriented

programming language (Python) •  Graphical preview and inspection tool (verify geometry AND

parameters) •  Flexible:

–  Very large and complex jobs are possible –  But it is also easy and fast to compose a simple experiment

29 25.000 tiles, 30 million dimples

Details Handled Automatically •  No worries about machine specific details, but focus on the

process

•  Automatic and exact timing for accurate sky-writing (correct delays set automatically)

•  Calibration system for scanner auto-alignment •  Automatic power calibrations: program the machine in watts

(instead of percent)

•  High resolving off-axis camera for accurate workpiece alignment and calibration

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Modular Micromachining System

•  Flexible and highly accurate workstation for micromachining and surface texturing

•  Ideal for R&D, flexible high-tech job-shops, process development

•  Can be customized into single purpose production machine

•  Standard system launched in summer 2014

•  Reproducible results by: –  Use of proven high quality components –  Handle machine specific details

–  Automated calibrations and power measurements

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Max Groenendijk Lightmotif B.V.

Pantheon 12 7521 PR Enschede

Tel: +31 (0)53 4500840 [email protected]

www.lightmotif.nl

Thank you for your attention