Ejection of molten material produced by pulsed electron and laser beams

Crater formation in electron and laser beam drilling is mainly due to molten material removal. In this process, there are two different modes of removal: ejection outside the target and transport of material which remains around the crater on the target surface. Measurement of these removal modes was carried out. The diameters of molten particles ejected from the targets were obtained. Characteristic particle diameters were determined for each material and each drilling condition. The volume of solidified material remaining around the crater was also obtained. From these results, the proportion of molten material ejected from the target was determined. Most of the molten material remained around the crater for iron and tungsten, but was ejected outside the target for aluminium and alumina ceramics.