Process characterisation of an additive manufacturing equipment : An analysis of the effect of electron beam powder bed fusion process parameters on the melt pool geometry and microstructure of Ti-6Al-4V

Sammanfattning: Additive manufacturing (AM) are manufacturing methods where components are produced by adding material layer by layer which allows for a high freedom of design as well as little or no material waste compared to conventional manufacturing methods. Despite the many benefits of AM there are still problems concerning the quality of the produced material. In this project an AM equipment was tested by using different process parameters and comparing their effect on the printed material. An electron beam powder bed fusion equipment was used and with varying values for beam power, scanning speed and preheat temperature. Initial tests were done using Ti-6Al-4V plates with a Ti-6Al-4V powder then being used for a few selected process settings. The EB-PBF did not act as predicted with varying beam powers compared to input values. Melting tracks using powder also proved to be difficult due to, for example, the build plate moving from being overcharged by the electron beam and the difficulty to control the powder layers. The geometry of printed tracks on plates was analysed and values for melt pool width, depth and height was measured. Both width and depth for the most part have a linear increase with increased power and line energy density. Preheating temperature has a smaller effect on the width and depth but leads to more even tracks.