PICALO 2006 Paper #1002 (Study of the Interplay of Vaporisation, Melt Displacement and Melt Ejection Mechanisms Under Single and Multiple Pulse Irradiation)

Study of the Interplay of Vaporisation, Melt Displacement and Melt Ejection Mechanisms Under Single and Multiple Pulse Irradiation
Authors:
J.M. Fishburn, Centre for Lasers and Applications, Macquarie University; Sydney Australia
Michael Withford, Centre for Lasers and Applications; Sydney Australia
D.W. Coutts, Centre for Lasers and Applications, Macquarie University; Sydney Australia
J.A. Piper, Centre for Lasers and Applications, Macquarie University; Sydney Australia
Presented at PICALO 2006

We have used a combination of profilometry, high speed imaging and recoil measurements using a ballistic pendulum to calculate the amount of material removed due t...

PICALO 2006 Paper #1003 (High Precision Laser Drilling with Ultra Short Pulses - Fundamental Aspects and Technical Applications)

High Precision Laser Drilling with Ultra Short Pulses – Fundamental Aspects and Technical Applications
Authors:
Christian Foehl, Forschungsgesellschaft Fuer Strahlwerkzeuge MbH; Stuttgart Germany
Friedrich Dausinger, Institut fuer Strahlwerkzeuge IFSW; Stuttgart Germany
Presented at PICALO 2006

In various industrial applications, for example in the automotive industry, the fabrication of micro-holes in metals is required. One application with the highest requirements is the production of fuel injection nozzles for diesel engines in the automotive industry. More and more smaller holes with well defined geometries are required to reach a more efficient combustion and to reduce the...

PICALO 2006 Paper #1004 (Laser Cutting and Joining of Wooden Materials: How Both Processes are Determined by the Heat Affected Zone)

Laser Cutting and Joining of Wooden Materials: How Both Processes are Determined by the Heat Affected Zone
Authors:
Stephan Barcikowski, Laser Zentrum Hannover E.V.; Hannover Germany
Presented at PICALO 2006

Wood and wood-derived materials are the most important materials with a world production of roughly 109 tons per year. However, because of the continuous development of the thermal and mechanical properties of wood materials towards high-tech applications, increasingly precise manufacturing processes have become attractive. In this contribution, the potential of laser cutting as well as laser welding of wooden materials is examined by quality-relevant material and process parameters as well...

PICALO 2006 Paper #1005 (Laser Cutting Ceramics using the Unstable Fracture Technique)

Laser Cutting Ceramics using the Unstable Fracture Technique
Authors:
Chwan-Huei Tsai, Huafan University; Taipei Hsien Taiwan
Jian-Shiun Shiu, Huafan University; Taipei Hsien Taiwan
Presented at PICALO 2006

This study proposes a new laser cutting method that uses the unstable fracture technique. In this method, a diamond blade is used to scribe a groove along the desired cutting path in an alumina substrate. A defocused CO2 laser is applied to the substrate surface. As the laser moves a short distance, a short crack is generated through the edge of the substrate. When the laser direction is reversed to close the crack tip, a great thermal stress is induced at the crack tip and caus...

PICALO 2006 Paper #1006 (Comparison of Front and Back Laser Irradiation in Laser Cleaning of Silica Particles from Silica Glass)

Comparison of Front and Back Laser Irradiation in Laser Cleaning of Silica Particles from Silica Glass
Authors:
Adam Joyce, Department of Physics; Sydney Australia
Deb Kane, Macquarie University; Sydney Australia
Presented at PICALO 2006

Laser cleaning of micron and sub-micron particles from various substrates such as silicon wafers and glass has been an active area of research in laser processing. Both understanding the fundamental physics of the light/particle/surface interaction and the development of successful cleaning protocols for industrial application have been drivers. Several groups have observed that directing the laser beam through a semi-transparent or transparent sam...

PICALO 2006 Paper #1007 (Cleaning Oxides from Copper Artifacts using a Frequency-doubled Nd:YAG Laser)

Cleaning Oxides from Copper Artifacts using a Frequency-doubled Nd:YAG Laser
Authors:
Alexander Kaplan, Luleå University of Technology; Lulea Sweden
Yang Sook Koh, Kiruna Center for Conservation of Property; Kiruna Sweden
John Powell, Laser Expertise Ltd.; Nottingham Great Britain
Göran berg, Luleå University of Technology; Luleå Sweden
Johnny Grahn, Luleå University of Technology; Luleå Sweden
Presented at PICALO 2006

This paper presents the results of an experimental program investigating the ablation of oxides from copper alloy surfaces using a frequency doubled Nd:YAG Laser. One eventual use for this technique would be in the feild...

PICALO 2006 Paper #101 (Application Potential of Laser with Strong Focusability)

Application Potential of Laser with Strong Focusability
Authors:
Christoph Deininger, Institut für Strahlwerkzeuge; Stuttgart Germany
Friedrich Dausinger, Institut fuer Strahlwerkzeuge; Stuttgart Germany
Jan Weberpals, Institut für Strahlwerkzeuge; Stuttgart Germany
Presented at PICALO 2006

Thin disk lasers as well as fibre lasers are distinguished by their good focusability and high efficiency. With the availability of the 4 kW thin disk laser, keyhole welding with focus diameters down to 75 µm became possible. This allows comparing the influence on the welding depth of the different focus diameter regimes that can be typically realized by lamp-pumped solid state a...

PICALO 2006 Paper #102 (New Considerations and Experimental Results on Laser Lap Welding of Zinc Coated Steel Sheets)

New Considerations and Experimental Results on Laser Lap Welding of Zinc Coated Steel Sheets
Authors:
Muhammad Muddassir Gualini, Pakistan Institute of Lasers and Optics; Islamabad Pakistan
Presented at PICALO 2006

Laser lap welding of zinc coated sheets needs still investigations in order to be properly inserted in production line. We have investigated several methods and already proposed a combined solution of cutting a slot and welding it over by a combined tandem of laser beams. We have further investigated the solution with theoretical and experimental work. We present our latest findings.

PICALO 2006 Paper #103 (Laser Welding with or without Shielding Gas?)

Laser Welding with or without Shielding Gas?
Authors:
Mark Faerber, LINDE AG; Hamburg Germany
Presented at PICALO 2006

Customers like to avoid expensive helium based shielding gases and thus laser welding without any gas is increasingly becoming popular. In practice, this means air is used as shielding gas and a mixture of oxygen and nitrogen, respectively. Both gases are effected by laser beam and plasma plume, these are dissociated and ionized and thus activated. Oxygen forms oxides which affect fatigue strength, nitrogen and nitrides affect formability of laser welded material. Degree of activation is influenced by type of laser and related temperature/ density of plasma plume. YAG lasers wo...

PICALO 2006 Paper #104 (Laser Joining of Aluminium to Titanium with Focus on Aeronautical Applications)

Laser Joining of Aluminium to Titanium with Focus on Aeronautical Applications
Authors:
Florian Wagner, BIAS Bremer Institut Fuer Angewandte Strahltechnik; Bremen Germany
Frank Vollertsen, BIAS Bremer Institut fuer angewandte Strahltechnik; Bremen Germany
Michael Kreimeyer, BIAS Bremer Institut fuer angewandte Strahltechnik; Bremen Germany
Rainer Kocik, Airbus Deutschland GmbH; Bremen Germany
Harald Kohn, BIAS; Germany
Presented at PICALO 2006

For aeronautical applications, hybrid structures made of titanium and aluminium alloys offer advantages in comparison to conventional designs. Due to the demands of the aircraft industry for new materi...