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Laser scanning confocal microscopy for 3D surface mapping
Lapšanská, Hana ; Schovánek, Petr
This contribution introduces a modern microscopic method and shows possible measurements and analysis of wire saw machined glass pieces. The main objective of realized measurements is to identify possible defects and its depth to propose eventual additional treatment. We are looking for the optimal technological procedure of grooved glass stick-on supports preparation. Such supports are used for the very thin accurate optical components production which is executed in our workshops and laboratories. Surface quality of the support significantly influences the quality of produced optical components.
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FEM simulation of pulsed laser seam welding
Lapšanská, Hana ; Havelková, Martina ; Chmelíčková, Hana
Welding simulations became very popular in last years because they can provide us with much interesting information about the internal material processes or heat source – material interactions. Usually continual seam welding was simulated. Since the pulsed laser welding systems were developed and disseminated, the need of pulsed welding simulations came out. Finite element SYSWELD welding simulation tool was adapted to model and simulate pulsed laser seam welding, also called spot overlapping welding. This paper describes basic principles of such simulation and shows some of its possible outputs.
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Laser welding of stainless steel tubes
Chmelíčková, Hana ; Lapšanská, Hana ; Hiklová, Helena ; Havelková, Martina
Laser axial welding is a modern method of production of tubes with seam which are mainly used in automotive and food-processing industry. Welding experiments with AISI 304L stainless steel sheet were conducted using continual high power CO2 laser with maximal power 5 kW. The aim of these experiments was to evaluate the effect of processing parameters on weld dimensions and surface properties. Subjected parameters were laser power, shielding gas flow and its composition. Modern contact profilometry was applied to display weld surfaces. Metallographic specimens of weld cross sections were prepared to measure the weldarea. Temperature field distribution was modeled using finite element software SYSWELD.
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Optimalizace parametrů laserového přetavování povrchu
Chmelíčková, Hana ; Kaňa, J. ; Hiklová, Helena ; Lapšanská, Hana ; Havelková, Martina
Laserový svazek s hustotou výkonu řádově 102 W.mm-2 způsobuje natavení povrchu kovů bez odpaření materiálu. Vzniká teplotní gradient mezi středem natavené stopy a rozhraní s pevnou fází, mění se struktura povrchu. Rychlost ochlazování ovlivňuje mikrostrukturu natavené oblasti. Výsledkem je zlepšení kvality povrchu, např. nízká porosita, homogenizace, zvýšení mechanické a chemické odolnosti. Na laserovém systému jsme provedli optimalizaci parametrů natavení povrchu vzorků z oceli ČSN 11 373 pomocí pulsního Nd:YAG laseru s průměrným výkonem 100 W. Proměnnými byly postupně energie a délka pulsu, rychlost posuvu a průměr stopy svazku. Natavené stopy byly podrobeny analýze pro zjištění mikrostruktury a rozměrů ovlivněných oblastí. Byla zjišťována závislost těchto výsledků na použitých parametrech procesu a vybrány jejich optimální hodnoty pro daný materiál.
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