Patent ID: 7011382
Filing Date: 2006-03-14
Classification: B23K,H05K

Abstract:
1. A method of improving the performance of a jetting assembly in an apparatus for jetting droplets of viscous medium on the fly onto a substrate, said jetting assembly being releasably mounted in said apparatus for jetting, said jetting assembly comprising a nozzle, an ejection mechanism connected to the nozzle, and a viscous medium container connected to the eject mechanism, the method comprising the steps of: obtaining information relating to an XY-position of the nozzle in relation to a calibration surface, the XY-position being the position of the nozzle in a plane parallel to the plane of the calibration surface, obtaining information relating to a Z-position of the nozzle, the Z-position being the distance between the nozzle and the calibration surface, determining the exit velocity a droplet of viscous medium has when said droplet exits said nozzle, and adjusting, on the basis of said information relating to an XY-position of the nozzle, said information relating to a Z-position of the nozzle and said exit velocity, a trigger position of the nozzle for the subsequent jetting of droplets, wherein said step of obtaining information relating to an XY-position of the nozzle comprises jetting at least one first droplet at a nominally predetermined location on said calibration surface, said at least one first droplet thereby forming at least one first deposit on said calibration surface, determining the offset of the location(s) of said at least one first deposit in relation to said nominally predetermined location, and determining, based on said determined offset, the XY-position of the nozzle, and wherein the step of determining the exit velocity comprises moving the nozzle relative the calibration surface at a first predetermined relative velocity in a plane parallel to the plane of said calibration surface, jetting, during said movement, at least one second droplet, said jetting being performed by triggering said ejection mechanism when said nozzle is at (a) predetermined location(s), said at least one second droplet thereby forming at least one second deposit on said calibration surface, determining the location(s) of said at least one second deposit, calculating the difference between said predetermined and said determined locations, altering the distance between the nozzle and the calibration surface with a predetermined distance, moving the nozzle relative the calibration surface at a second predetermined relative velocity in a plane parallel to the plane of said calibration surface, jetting, during said movement, at least one third droplet, said jetting being performed by triggering said ejection mechanism when said nozzle is at (a) predetermined location(s), said at least one third droplet thereby forming at least one third deposit on said calibration surface, determining the location(s) of said at least one third deposit, calculating the differences between said predetermined and said determined locations, and determining, based on said calculated differences between said predetermined and said determined locations of said at least one second and at least one third deposits, the exit velocity a droplet of viscous medium has when said droplet exits said nozzle.