In the paper a new original approach on active Q-switching of a fiber laser by using a single crystal LiTaO3 photo-elastic modulator is presented first time. This induces due to the photo-elastic effect a modulated artificial birefringence which modulates the polarization of passing light. When used together with a polarizer inside a laser cavity the laser photon life time is strongly modulated and the laser may start to emit laser pulses. We realized this with a fiber laser based on a 5m long double clad Nd-doped fiber. The pulse repetition frequency was 400 kHz and the pulse duration 300ns.
COBISS.SI-ID: 9991451
Acoustic waves generated during GMAW process were measured in surrounding air and in weld-pieces using a microphone and PZT sensor. To evaluate influences on sound generation extensive experiments were performed with two different unalloyed carbon steels using two types of shielding gas and varying distance between welding nozzle and weld-piece. Results indicate that the main source of acoustic waves in short circuit metal transfer mode is arc reignition. From acoustic signals one can easily assess process stability and detect welding conditions resulting in weld defects.
COBISS.SI-ID: 7060251
In this research, the role of the lead time scheduling of operations of orders within the whole production planning and control process is elaborated. Computer-aided procedures, needed to determine the real mean lead time of operations, and the real lead time scheduling of operations of orders are proposed. The results of determining mean lead times of operations, and the lead time scheduling of operations of orders, that was carried out in a company which produces equipment for civil engineering, are reported.
COBISS.SI-ID: 7237147
Measurements of the laser induced cavitation bubble and shock wave are presented using a combination of a beam-deflection probe and an arm-compensated interferometer. The interferometer was used to determine the relative position of the laser-induced breakdown. The time-of-flight data from the breakdown site to the probe beam yielded the velocity, and from the velocity the shock-wave pressure amplitudes were calculated. Two regions were found where the pressure decays with different exponents, pointing to a strong attenuation mechanism in the initial phase of the shock-wave propagation.
COBISS.SI-ID: 8259611
A novel approach to on-line measurements of the steel plate surface deformations during various types of laser processing, e.g., engraving, marking, cutting, bending, and welding is presented. The measuring system is based on a laser triangulation principle, where the laser projector generates multiple lines simultaneously. This enables one to measure the shape of the surface with very high sampling rate and accuracy.
COBISS.SI-ID: 7582491