Black, white and color marking by using a nanosecond fiber laser

Laserji so na področju industrije vedno bolj uporabljeni in izpodrivajo konvencionalne načine obdelave površin. En izmed pomembnih namenov njihove uporabe je tudi označevanje oz. dekorativno barvanje materialov, saj je postopek relativno hiter in poceni. V nalogi se ukvarjamo z iskanjem optimalnih parametrov za nastanek določenih barv na nerjavnem jeklu in pojasnimo, zakaj do nastanka barve sploh pride. Vzorce smo označevali z laserskim sistemom, ki je sestavljen iz nanosekundnega vlakenskega laserja, skenirne glave z F-theta lečo z goriščno razdaljo 163mm, pozicionirnega sistema in programskega grafičnega vmesnika SCAPS SAMLight. Rezultate smo ovrednotili pod optičnim mikroskopom, eksperimente pa smo v celoti izvedli na vzorcih nerjavnega jekla AISI 304. Na koncu naloge smo lasersko izdelali tudi barvno fotografijo. Z eksperimentiranjem smo uspeli določiti parametre za izdelavo bele in črne oznake ter sledečih barvnih odtenkov: rožnatega, vijoličnega, oranžnega, rumenega, modrega in zelenega. Pokazali smo tudi, kako povprečna moč bliskov, hitrost vodenja snopa, frekvenca in oblika bliskov ter razmiki med linijami, s katerimi označujemo, vplivajo na nastanek barvnih odtenkov. Poleg tega smo pokazali, da ima pri laserskem barvanju pomembno vlogo kot, pod katerim vodimo laserski snop.Lasers are increasingly used in the field of industry and displace conventional ways of surface treatment. One of the important purposes is decorative color marking of materials, because it is relatively quick and cheap. In this thesis we are dealing with finding optimal parameters for the formation of certain colors on the stainless steel and explain, why color occurs. Samples were marked with a laser system consisting of a nanosecond fiber laser, a scanning head with an F-theta lens having a focal length of 163mm, positioning system and a graphical user interface SCAPS SAMLight. Results were evaluated by using an optical microscope. Color marking was made on samples of stainless steel AISI 304. At the end of this thesis, we also used a laser to mark the color photography. By experimentation we were able to determine parameters for producing white and black marks as well as the following colors: pink, purple, orange, yellow, blue and green. We also examined, how laser parameters, such as average power, marking speed, pulse frequency, pulse duration and line separation distance influence on appearance of different colors. Additionally, we have shown that the angle of marking lines plays an important role in laser color marking