Hi Gareth, You could look at the following reference - this is for one-time actuation during self-assembly, but it may be of interest to you nonetheless. Equilibrium of hinged and hingeless structures rotated using surface tension forces Syms, R.R.A. (Imperial Coll of Science, Technology and Medicine) Source: Journal of Microelectromechanical Systems, v 4, n 4, Dec, 1995, p 177-184 Regards, Michael _________________________________________________________________ It's fast, it's easy and it's free. Get MSN Messenger today! http://www.msn.co.uk/messenger