Overview and numerical analysis of 3D printing of steel

Abstract

3D laser metal printing is used to build up work pieces layer by layer from powderized or solid metal with the help of high-power laser welding. The latter process replaces conventional machining more and more due to the advantages of neglectible material loss and absence of tool wear,although disadvantages are a relatively low processing speed and sometimes necessary postprocessing. Two options are mainly used,namely the selective melting of preplaced metal powder with travelling laser (SLM) and also the melting down of a flow of powderized metal or solid metal wires with travelling nozzle and laser (LMD) where in the latter case the work piece volume is more or less unlimited but a health risks exists due to inhaled powder,both associated to the absence of housing . In the actual paper these two options are treated in detail where first of all the mechanical set up and its function are explained followed by a numerical analysis of the LMD process that can easily be used also for the SLM process and covers the phenomena ultimately necessary to run the processes .It demonstrates the influence of the main parameters as laser power,focus shape and size,travelling speed and others on the temperature of the molten material,layer width and thickness and in consequence on building rate and helps thus to optimize equipment and process. It is expected that these processes have a bright future especially if the development of enhanced processing speed will be successful.