A thousand holes every second

Connect, no.106, May-June 2000, p.7

During welding the molten material flows from one side of the hole to the other as the keyhole is traversed through the material being welded. In drilling, the molten material is literally blown out of the hole leaving it with cleansides.

EB texturing is different to both the above processes. Little material is lost, instead the molten material is redistributed in a controlled fashion around the side of every hole that is formed. This can be used to make novelsurface textures with increased surface area or re-entrant features for bonding. The surface, once treated in the clean vacuum environment, is unlikely ever to be cleaner than it is immediately after processing thus making thistechnique potentially useful as a pre-treatment since it may well obviate a later cleaning operation.

EB texturing is fast. Even at relatively low powers such as ~2kW, a thousand tiny cavities can be formed every second in many materials - 3.6 million every hour - 28 million over an eight hour shift.

Contact Bruce Dance for more details on this process. E-mail: bruce.dance@twi.co.uk