Christoph Hamann

Laser Machining Of Ceramic And Silicon

Ceramics and silicon are brittle materials, a fact that may cause problems and at the same time be helpful while machining with lasers. After giving a short introduction to ceramics different ways of cutting and drilling alumina (Al203) and silicon (Si) are discussed and compared to conventional methods. Examples from electronics industry with regard to types of laser, quality and velocity of process are presented.

Acoustic Emission And Its Application To Laser Spot Welding

A simple method for noncontact measuring acoustic emission generated during laser welding of steel X5CrNi18 9 and pure aluminium is presented. Laser beam quality is kept constant to insure that AE signal is just affected by the weld process. It will be shown that measuring in noncontact manner depends on formation of plasma, otherwise AE is generated due to backscattered laser radiation, which heat the fixture of the AE sensor.

Relaisfederjustierung mittels gepulster Nd:YAG-Laser

Das KRD 2 ist ein Miniaturrelais fur Schwachstromanwendung mit 2 Wechsler-Kontakten, siehe Bild 1 /U. Kobler/. Die beiden Mittelfedern sind als Doppelkontakte ausgebildet und werden aus einem stufig gefrasten Band durch Stanzen und Biegen gefertigt. Im Laufe der Fertigung werden an die Mittelfedern je eine Stromzufuhrung — aus hochleitfahigem Material — mit je zwei Laserschweispunkten befestigt. Die durch die einzelnen Fertigungsschritte entstandenen Toleranzen ergeben eine zu grose Streubreite und wurden sowohl die Kontaktgabe als auch das Schaltverhalten des Relais negativ beeintrachtigen.

Absorption Behaviour of Solder Pastes in Laser Soldering

The aim of these investigations is to examine various solder pastes for their absorption behaviour with respect to laser beam of wavelength of 1.06 μm. It is intended to varify the importance of absorption of flux over metallic composition and reactivity of flux.

Investigations for Detection of Splashes and Throughweld when Spotwelding with Pulsed Nd: YAG-Laser

Acoustic emission (AE) has been used by several authors to determine weld quality of laser beam welded samples. Of these, /1/ and /2/ use the same signal shape to detect different results. In each case the signal envelope consists of two distinct maxima. Stark claims that the second maximum reveals formation of splashes whereas Weeter finds this signal when sample is not welded through. It will be shown that second maximum is signal for splashes as well as incomplete weld through and that no second maximum occurs when welding through, even if splashes are present.