John, I recommend you get your hands on a catalog from IDI. Page 102 has a thorough description of pointing accuracy calculation, including examples. IdI's address is 5101 Richland Ave., Kansas City, KS 66106. 913-342-5544 Richard [log in to unmask] [log in to unmask] wrote: > All, > > I luckely found some calculations for determining pin deflection, hole > diameter, pin length, hold (yes HOLD) diameter, etc. for Testing Fine > pitch devices (.010", .012") and BGAs. > > Is anyone familiar with these formulas? > > HSmin = SD + PT (tanO) > > 0 = sin-1 (Pd/Pl) > > HSmin = (SD + PT)(PD/PL) > > LEGEND > > HSmin - min hold diameter > SD - shaft diameter > PT - plating thickness > 0 - angle of deflection > PD - pin deflection > PL - pin length > > Can I use these formulas to determine if testability is feasible, for > a very high dense assembly {4 - 600 I/O BGAs with 30 - .020" pitch > devices (160-pin nominal) in a 9 x 7 form factor}. I feel I am > missing several pieces to the overall formula picture. Can someone > advise where I can obtain the rest of the equation. > > John Gulley > > ################################################################ > TechNet E-Mail Forum provided as a free service by IPC using LISTSERV 1.8c > ################################################################ > To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body: > To subscribe: SUBSCRIBE TechNet <your full name> > To unsubscribe: SIGNOFF TechNet > ################################################################ > Please visit IPC web site (http://jefry.ipc.org/forum.htm) for additional information. > For technical support contact Hugo Scaramuzza at [log in to unmask] or 847-509-9700 ext.312 > ################################################################