US 11,673,230 B2
Method and apparatus for removing a conformal coating from a circuit board
Ebrahim Ghanbari, London (GB)
Appl. No. 16/772,371
Filed by HZO, Inc., Morrisville, NC (US)
PCT Filed Dec. 3, 2018, PCT No. PCT/GB2018/053495
§ 371(c)(1), (2) Date Jun. 12, 2020,
PCT Pub. No. WO2019/122810, PCT Pub. Date Jun. 27, 2019.
Claims priority of application No. 1721176 (GB), filed on Dec. 18, 2017.
Prior Publication US 2021/0078136 A1, Mar. 18, 2021
Int. Cl. B24C 1/00 (2006.01); B24C 1/08 (2006.01); B24C 3/32 (2006.01); H05K 3/22 (2006.01)
CPC B24C 1/003 (2013.01) [B24C 1/086 (2013.01); B24C 3/322 (2013.01); H05K 3/22 (2013.01)] 13 Claims
OG exemplary drawing
 
1. A method of removing a conformal coating from a circuit board coated with said conformal coating, the method comprising:
subjecting the circuit board to a jet comprising dry-ice particles ejected from a nozzle, to remove said conformal coating from said circuit board, wherein the nozzle is positioned relative to the circuit board such that an axis parallel to an elongated shaft of the nozzle forms an angle with an axis normal to the circuit board of between 45 degrees and 60 degrees; and
systematically rotating the jet and systematically rotating the circuit board relative to each other, wherein the jet additionally comprises air ejected from the nozzle, wherein the air from the nozzle is ejected at a flow rate of from 1 to 2 m3/minute, and wherein the air ejected from the nozzle is fed into the nozzle at a pressure of from 3 to 4 bar, and wherein the method further comprises utilizing a rotating screw to reduce a size of the dry ice particles as they pass through a dry ice input channel on the nozzle.