4M Knowledge base - papers
Application of Different Process Chains for Polymer Microfluidics Fabrication including Hybrid Tooling Technology
G. Tosello(a), B. Fillon(b), S. Azcarate(c), A. Schoth(d), L. Mattsson(e), C. Griffiths(f), L. Staemmler(g), P.J. Bolt(h)
a: Technical University of Denmark (DTU), Department of Manufacturing Engineering and Management (IPL), 2800 Kgs. Lyngby, Denmark
b: French Atomic Energy Commission (CEA), Laboratory of Innovation for New Energy Technologies and Nanomaterials (LITEN), 38054 Grenoble, France
c: Tekniker Technological Center, 20600 Eibar, Spain
d: University of Freiburg, Institute of Microsystem Technology (IMTEK), 79110 Freiburg, Germany
e: School of Industrial Technology and Management (KTH), Department of Production Engineering, 100 44 Stockholm, Sweden
f: Cardiff University, Manufacturing Engineering Center (MEC), Cardiff CF 24 3AA, UK
g: Hahn-Schickard-Gesellschaft, Institute for Micro Assembly Technology (HSG-IMAT), 70174 Stuttgart, Germany
h: TNO Science & Industry, 5600 HE Eindhoven, The Nederlands
This paper is based on the Division 4 “Processing of Polymers” activities within the 4M NoE “Multi-Material Micro Manufacturing”. To overpass limitations of the current existing micro tooling capabilities, a new generation of micro hybrid tooling technologies for micro replication was developed. A metrological approach was applied to standardize the employed tooling processes (μ-milling, μ-EDM, laser μ-machining, electrochemical μ-milling). The micro tools were then tested with different polymers. The paper provides a comparison of these technologies concerning obtainable feature sizes, surface finishing, and aspect ratios of both micro tools and micro moulded parts.
D. Karnakis, G. Rutterford, M. R. H. Knowles
Oxford Lasers Ltd., Unit 8, Moorbrook Park, Didcot, Oxfordshire OX11 7HP, UK
We describe high power diode-pumped solid-state (DPSS) laser micro-machining results of commonly used industrial materials such as stainless steel and silicon. Frequency up-converted lasers were used at 532nm and 355nm. We discuss the benefits of high laser intensity (~ GW/cm2) micro-machining for efficient laser microfabrication.
At such high irradiance conditions material properties are approaching their critical limits and ablation mechanisms are complex. These can be exploited to our advantage in particular for micro-drilling and micro-cutting small feature sizes in the order 10-20 μm and high aspect ratios of up to 20:1. Etch rate data are presented and a comparative study of the ablation efficiency in these materials is discussed. Results of single shot and multiple shot ablation are also presented. The potential applications of this technology to device singulation for electronic and power generation devices will be described.
S. Wilson (a),(b), W.Pfleging (c), A. Welle (d), P.Kirby (b), M.Przylbyski (e)
(a) Institute for Microstructure Technology, Forschungszentrum Karlsruhe, 76344 Eggenstein-L, DE
(b) School of Applied Sciences., Cranfield University, Cranfield, Beds. MK43 0AL, UK
(c) Institute for Materials Research 1, Forschungszentrum Karlsruhe, 76344 Eggenstein-L, DE
(d) Institute for Biological Interfaces, Forschungszentrum Karlsruhe, 76344 Eggenstein-L, DE
(e) ATL Lasertechnik GmbH, Burger Str. 48, 42929 Wermelskirchen, Germany
Laser patterning is of interest for MST applications; direct ablation of polymer material for generating 2D and 3D shapes such as microfluidic channels, curved shapes or micro-holes and alternatively photo-induced change of chemical or physical surface properties. Correct laser choice and process parameters enables new approaches for the fabrication of lab-on-chip devices with integrated functionalities. Laser-assisted ablation and modification of polystyrene (PS) is introduced with respect to the fabrication of polymer devices for high throughput planar patch clamping - a method of measuring the electrical activity of a cell currently a focus for high throughput systems (HTS). There are currently no marketed systems using novel materials that have surface modifications for either individual cell placement, or for dealing with cell networks, a physiologically important consideration for tissue engineering and understanding cell to cell interactions.
Within 4M, a design jointly proposed by FZK and Cranfield University for the fabrication of a polymer patch clamping system, laser micro-drilling of PS and subsequent surface functionalisation for cell adhesion has been investigated as a function of laser and process parameters. High power ArF laser with a pulse of 20 ns as well as high repetition ArF excimer laser sources with pulse lengths of 4-6 ns were used in order to study the influence of laser pulse length on laser drilling and laser induced surface modification. Micro-drilling of PS with diameters down to 1.5 μm have been demonstrated. Furthermore, localized formation of chemical structures suitable for improved single cell and cell network adhesion has been achieved on PS surfaces.
M.R.H Knowles, G. Rutterford, D. Karnakis, A. Ferguson
Oxford Lasers Ltd, Unit 8, Moorbrook Park, Didcot, OX11 7HP, UK
Laser micro-processing is an enabling technology that facilitates component minaturization and improved performance characteristics. It is being applied across many industries – semiconductor, electronics, medical, automotive, aerospace, instrumentation, and communications. Laser ablation of metals, ceramics and polymers is a complex process and the exact nature of the interaction is specific to the material and laser processing parameters used. Ablation is usually a combination of evaporation and melt expulsion. In order to achieve the highest quality results it is often desirable to minimize the degree of melting involved and short pulse lasers show certain advantages in this respect. We discuss the benefits of high laser intensity (GW/cm)^2 on target for efficient laser micro-fabrication in metals and ceramics. At such high irradiance conditions, material properties are approaching their critical limits and ablation mechanisms are becoming even more complicated but can be exploited to our advantage in particular for high aspect ratio micro-drilling and micro-cutting.
Micromachining of amorphous and crystalline Ni78B14Si8 alloys using micro-second and pico-second lasers
I. Quintana (1), T. Dobrev (3), A. Aranzabe (2), G. Lalev (3), S. Dimov (3)
(1) CIC marGUNE. Pol. Ibaitarte 5, 20870; Elgoibar; Guipúzcoa, Spain
(2) Manufacturing Processes Department, Fundación Tekniker, Av. Otaola 20, 2060, Eibar, Guipúzcoa, Spain
(3) Manufacturing Engineering Centre, Cardiff University, Cardiff, CF24 3AA
The machining response of amorphous and polycrystalline Ni-based alloys (Ni78B14Si8) to micro-second and pico-second laser processing was investigated. The shape and topography of craters created with single pulses as a function of laser energy together with holes drilled in both materials were studied. The carried out FIB analysis of craters in amorphous and polycrystalline samples revealed that processing both with micro-second and pico-second lasers does not lead to materials crystallization and the short-range atomic ordering of metallic glasses can be retained. When processing the amorphous sample the material laser interactions resulted in a significant ejection of molten material from the bulk that was then followed by its partial re-deposition around the craters. Additionally, there were no signs of crack formation that indicate a higher surface integrity after laser machining. A conclusion is made that laser processing both with short and long pulses is a promising technique for micromachining metallic glasses because does not lead to material crystallisation.
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