Inteligent monitoring system for laser cladding

Lasersko navarjanje je postopek, namenjen predvsem popravilu poškodovanih strojnih elementov, obnovi površin in nanašanju raznovrstnih materialov na substrat, z namenom povečanja površinske trdote ali drugih površinskih lastnosti. Zaradi velikih temperaturnih gradientov in metalurških razlik med materiali se na površini ter na stiku navara z osnovnim materialom pojavljajo razpoke. Prav tako lahko zaradi premajhnih vnosov energije ali nepravilnega gorišča laserskega žarka pride do nezvarjenih mest med navarom in substratom ter posledično tudi do odstopanja materiala. V podjetju EMO – Orodjarna, d. o. o., poskušajo omenjene težave odpraviti z uporabo inteligentnega sistema za spremljanje laserskega navarjanja. Sistem z uporabo termo kamere spremlja temperaturo talilnega bazna in na podlagi le-te spreminja moč laserja. Z regulacijo moči laserja dosežemo bolj enakomerne temperaturne razmere v navaru, kar ugodno vpliva na proces navaranja in pojavljanje razpok. S poskusom smo poiskali parametre, pri katerih smo dosegli največji izkoristek postopka in ugotavljali vpliv regulacije na pojav razpok. Rezultati so pokazali, da sistem izboljša gostoto navara in deloma zmanjša količino in velikost razpok, jih pa pri opazovalnih kombinacijah materialov ne odpravi povsem. Pri obravnavanih materialih bi morali za popolno odpravo razpok substrat predgreti.Laser cladding is a process used mainly for repairing damaged elements of machines, renewing surfaces and adding different materials on a substrate to achieve greater hardness of the surface or other surface features. Due to high temperature gradients and metallurgic differences between materials, cracks appear on the surface of weld metal and the contact point with the base material. Lack of input energy or displacement of the focal point of the laser beam can lead to unwelded areas between a clad and a substrate and consequently to the deviation of clad from the base material. In the EMO Orodjarna d.o.o. company they are trying to resolve the noted issues with the use of an intelligent system for the control of laser welding. The system uses a thermal imaging camera to monitor the temperature of the melting pool and based on the gathered information adjusts the power and speed of the laser. By adjusting the power and speed of the laser more even temperature conditions in the weld are achieved, which is beneficial for the process of welding and reducing the occurrence of cracks. In the experiment we searched for working parameters in which the highest efficiency of the process was achieved and studied the influence of laser beam regulation on the occurrence of cracks. The results showed that the system improves the density of the clad and partially reduces the quantity and size of the cracks, although it did not eliminate them entirely in the studied combinations of materials. For a complete elimination of cracks in the selected experimental materials, the substrate should be preheated