Dan, The rule of thumb that I had heard from a solder paste application engineer was that you should be able to fit 8 solder balls across your smallest aperture width. I am not sure your 0201 solder paste aperture will work very well (unless you made a typo). .13mm x .26mm is really, really small. If your foil size is .076mm (.003") or greater, your aspect ratio is below .6 You really need to be around .3mm x .35mm or .34mm square if your foil size is .13mm. This puts your AAR over .66 Steve A > -----Original Message----- > From: Dan R. Johnson [SMTP:[log in to unmask]] > Sent: Thursday,December 20,2001 8:19 AM > To: [log in to unmask] > Subject: Re: [TN] mesh size > > Thanks John, this confirms what I thought. I don't know if you could say > the aspect ratio is "right" but I am using a .13X.26mm paste pad. This is > an Rf application and the design engineer is adamant that all component > pads be as small as possible. > You mentioned the ball size to aperture size ratio, is there a "rule of > thumb" for this? > Dan --------------------------------------------------------------------------------- Technet Mail List provided as a free service by IPC using LISTSERV 1.8d 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 delivery of Technet send the following message: SET Technet NOMAIL Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail Archives Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 ---------------------------------------------------------------------------------