Grundlegende Untersuchungen ueber Einsatzmoeglichkeiten von Excimerlasern zur Oberflaechenvorbehandlung schwer klebbarer Werkstoffe Schlussbericht

Within the reported project polypropylen and carbon fiber composites were irradiated with UV-laser radiation. The aim was to enhance their adhesive properties. When polyolefines are irradiated with UV-light under certain conditions it is known that carbonyl und hydroxyl groups are formed. These functional groups enhance the adhesive forces. In experimental investigations with different excimer lasers it was shown that these groups are formed, especially if the treatment is done in oxygen. Destructive strength measurements showed that arising of these groups enhances the tensile strength. When carbon fiber compounds are treated with excimer laser light it is possible to remove the matrix resin without damaging the fiber. It is also possible to remove the resin inside without damaging the fiber. (orig./RHM)Im Rahmen des dokumentierten Forschungsvorhabens wurden Untersuchungen zur UV-Laserstrahlvorbehandlung von Polypropylen und kohlenstoffaserverstaerkten Kunststoffen durchgefuehrt. Das Ziel war es, die adhaesiven Eigenschaften dieser Werkstoffe zu verbessern. Von den Reaktionsverlaeufen beim Bestrahlen von Polyolefinen mit UV-Licht ist bekannt, dass sich unter bestimmten Bedingungen Carbonyl- und Hydroxylgruppen bilden. Diese Gruppen wirken Adhaesionskraefte verstaerkend. Es zeigte sich bei experimentellen Untersuchungen am Polypropylen mit verschiedenen Excimerlasern, dass polare Gruppen in Abhaengigkeit von der Umgebungsatmosphaere entstehen, bevorzugt bei Behandlung in Sauerstoffatmosphaere. Festigkeitsuntersuchungen haben ergeben, dass mit dem Entstehen dieser Gruppen ein Ansteigen der Zugscherfestigkeit verbunden ist. Bei der Bearbeitung von CFK-Verbundwerkstoffen mit UV-Laserlicht war es moeglich, mit Matrixharz bedeckte Fasern freizulegen, ohne die Fasern selbst anzugreifen. Auch ist ein Abtrag tieferliegenden Harzes moeglich, so dass z.B. guenstige Voraussetzungen fuer Reparaturzwecke geschaffen sind. (orig./RHM)Available from TIB Hannover: F94B0663+a / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEBundesministerium fuer Forschung und Technologie (BMFT), Bonn (Germany)DEGerman

Untersuchungen an Strahlfuehrungs- und -formungskomponenten zur grossflaechigen strukturierten photochemischen Oberflaechenbearbeitung mit Excimerlasern Endbericht

Investigations were made in a system for photolytical treatment of surfaces with excimer lasers. In principle the idea was to design and to build up a flexible system, which could be used for large area photochemical processes with good resolution. In theoretical considerations concepts were made for beam delivery and -forming, diagnostics, autofocus and sample transfer. These components were built up and tested first separately and then in a complete set-up. All important parts were connected by modular structured PC-control. This allows nearly automated drive of processing sequences. The beam forming was done by Koehler illumination principle. For diagnostic and control of the beam characteristics different CCD-cameras were used and special PC-software was written. Additionally software algorithm with appropriate hardware for autofocusing was implemented to enhance its accuracy. The laser process itself can be done in air or in different atmospheres. Several important parameters are controlled during the process. If a correction is necessary, it is done immediately. Irradiation of photoresist layers on glass substrates showed that the focus position is found exactly. It was possible to get images with high resolution. Positive photoresists can be developed with fine structures and without ablation. The reproducibility is also very good. The treated area now is 20 x 20 mm"2 with a resolution of 4 #mu#m. If for instance optical elements with best quality were taken, these values can be increased. In order to give limiting values further investigations are necessary. (orig.)Available from TIB Hannover: F94B0755+a / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEBundesministerium fuer Forschung und Technologie (BMFT), Bonn (Germany)DEGerman

Hochrate. Grundlagenuntersuchungen zur Erhoehung des energetischen Wirkungsgrades lasererzeugter Partikelstroeme. Teilvorhaben: Untersuchungen zur Bildung von Partikelstroemen mit UV-Laserstrahlung Abschlussbericht

Subject of the project was the investigation of fundamental processes of the formation of particle fluxes at pulsed laser irradiation of solid targets with high energetic pulsed UV excimer laser radiation. It has been shown, that the parameters of particle fluxes (plasma composition, density, ionisation degree, energy distribution of the particles, deposition rate) strongly depend on the laser parameters. As a result optimal deposition conditions can be choosen with regard to desired film properties. Under certain conditions the deposition rate could be increased up to two orders of magnitude. (orig.)Available from TIB Hannover: F99B121+a / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEBundesministerium fuer Bildung, Wissenschaft, Forschung und Technologie, Bonn (Germany)DEGerman

Grundlegende Untersuchung des lasergestuetzten nasschemischenAetzens fuer die direkte Mikrostrukturierung Abschlussbericht

The fundamentals of direct lasermicrostructuring of solids by laser activation of chemical etching reactions in liquids have been investigated. Detailed investigations on the physical and chemical mechanism on metals have been performed, which provided insight into the temporal evolution of laser-induced etching reactions. In addition, technological fundamentals of the method have been developed, which can be used as a foundation for the development of technical manufacturing processes. (orig.)Available from TIB Hannover: DtF QN1(57,39) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEBundesministerium fuer Bildung, Wissenschaft, Forschung und Technologie, Bonn (Germany)DEGerman

Grundlegende Untersuchungen zur praezisen Bearbeitung von dreidimensionalen Strukturkoerpern durch thermochemisches Laserabtragen Abschlussbericht

SIGLEAvailable from TIB Hannover: F01B47+a / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Bildung und Forschung, Berlin (Germany)DEGerman