Forming a perforate membrane by laser drilling and a subsequent electro-polishing step

• Main Author: BLAKEY DAVID MARK
• Format: Patent
• Language: English
• Published: 08.01.2008
• Subjects: APPARATUS THEREFOR; APPLYING LIQUIDS OR OTHER FLUENT MATERIALS TO SURFACES, IN GENERAL; ATOMISING APPARATUS; BLASTING; CHEMISTRY; CLADDING OR PLATING BY SOLDERING OR WELDING; COMBINED OPERATIONS; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; HEATING; LIGHTING; MACHINE TOOLS; MECHANICAL ENGINEERING; METAL-WORKING NOT OTHERWISE PROVIDED FOR; METALLURGY; NOZZLES; OTHER WORKING OF METAL; PERFORMING OPERATIONS; PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL; POSITIVE DISPLACEMENT MACHINES FOR LIQUIDS; PROCESSES FOR THE ELECTROLYTIC REMOVAL OF MATERIALS FROMOBJECTS; PUMPS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS; SEPARATION; SOLDERING OR UNSOLDERING; SPRAYING APPARATUS; SPRAYING OR ATOMISING IN GENERAL; SUCH WORKING COMBINED WITH OTHER FORMS OF WORKING OF METAL; TRANSPORTING; UNIVERSAL MACHINE TOOLS; WEAPONS; WELDING; WORKING BY LASER BEAM; WORKING OF METAL BY THE ACTION OF A HIGH CONCENTRATION OFELECTRIC CURRENT ON A WORKPIECE USING AN ELECTRODE WHICH TAKESTHE PLACE OF A TOOL

A method of forming a perforate membrane ( 1 ) is disclosed for use in a liquid transport device. The membrane has at least plural nozzles ( 10 ) formed therethrough. Each of those nozzles has a throat portion ( 12 ) opening at opposite end through opposite surface ( 2 ') of the perforate membrane and a smoothly curved outwardly diverging portion ( 11 ) extending from the first end of the throat portion to the first surface ( 2 ) of the perforate membrane. Laser energy is applied selectively to the first surface ( 2 ) of the membrane in the form of a pulsed, focused beam to form the nozzles ( 10 ) and thereafter the first surface ( 2 ) of the membrane and the surface of the diverging portion ( 11 ) of the nozzles ( 10 ) are electro-polished to remove surface imperfections. The electro-polishing is controlled so as to remove material from the surface of the diverging portion ( 11 ) of the nozzles to a depth less than the length of the throat portion ( 12 ).