I am dealing with an intermittent solder bridging on a BGA package- about 5 percent of the time. One avenue to make the process more robust I was looking at was redesigning the stencil aperture. I am currently using a 33 mil square solder aperture giving a paste volume of 2722 cubic mils (with a 5 mil stencil). This reduced the incidence of bridging - the previous stencil was 6 mils thick and had a print volume of 3267 cubic mils. The ratio of the stencil aperture to the stencil aperture area is 92% The sphere diameter on the package is 24 mils and the pitch is and in the past I have made stencil apertures 2 mil larger than the maximum diameter- in this case the volume would be 1540 cubic mils. The ratio of the stencil aperture wall to the stencil print area for a round aperture is 52%. I spoke with the supplier of the component but they had no recommendations and a cursory Google search provided no additional information so I thought I ask the Technet folks. Thanks Tom --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 15.0 To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 -----------------------------------------------------