US 7,316,067 B2
Forming a perforate membrane by laser drilling and a subsequent electro-polishing step
David Mark Blakey, Herts (United Kingdom)
Assigned to The Technology Partnership, Melbourn Royston, Hertz (United Kingdom)
Appl. No. 10/489,327
PCT Filed Sep. 06, 2002, PCT No. PCT/GB02/04093
§ 371(c)(1), (2), (4) Date Jul. 30, 2004,
PCT Pub. No. WO03/026832, PCT Pub. Date Apr. 03, 2003.
Claims priority of application No. 01308106 (EP), filed on Sep. 24, 2001.
Prior Publication US 2005/0006359 A1, Jan. 13, 2005
Int. Cl. B23P 15/16 (2006.01); B05B 1/00 (2006.01); B23K 26/00 (2006.01); B23H 3/00 (2006.01)
U.S. Cl. 29—896.6  [29/890.142; 29/890.143; 239/596; 239/601; 219/121.71; 205/640; 205/641] 18 Claims
OG exemplary drawing
 
1. A method of forming a perforate membrane for use in a liquid transport device, by applying laser energy selectively to a first surface of the membrane in the form of a pulsed, focused beam to form a plurality of nozzles each having a throat portion opening of a selected diameter at one end through the opposite surface of the perforate membrane and a smoothly curved outwardly diverging portion extending from the other end of the throat portion to the first surface of the perforate membrane, and further comprising the steps of:
thereafter electro-polishing the first surface of the membrane and the surface of the diverging portion of the nozzles to remove surface imperfections, and controlling the electro-polishing so as to remove material from the surface of the diverging portion of the nozzles to a depth within the membrane less than the length of the throat portion so that the diameter of the throat portion is unchanged by the electro-polishing step.