Brad, What is inexpensive? All relative, I suppose. When I was still with Nortel Networks, I carried out a couple of studies in this area using a four figure analytical balance. I was able to produce very good, smooth curves of the moisture absorption/adsorption and the corresponding moisture loses with different heating regimes. However, a four figure balance is a precision piece of equipment, not something you put in the hands of just anybody. It also must be in a draft-free, vibration-free, dust-free zone. As far as Jim's statement of always baking out BGA's before use, we (Nortel) did not find this necessary if they were used directly out of the moisture resistant bag right after they came in the door or if they were stored in dry storage cabinets after arriving as just described. If either of these two conditions were not in play, then, yes, I agree with Jim regarding baking. Some conditions that might cause this to be necessary would be rips in the incoming "sealed" bag, forgetting to put into dry storage, too much time on a board before second side reflow or wave soldering. Bev Christian Director of Electronics Manufacturing XLTEK -----Original Message----- From: Brad L. Matthies [mailto:[log in to unmask]] Sent: Tuesday, October 17, 2000 12:34 PM To: [log in to unmask] Subject: [TN] Measuring Moisture in BGA Packages. TN, Does anyone know of a simple (i.e., inexpensive) way to measure the moisture content in a BGA package? We have thought about measure the weight of parts, baking them out and remeasuring the weight to determine if it dropped. We have also considered using infrared imaging to look at the parts after applying some heat to them. Both of these seem problematic though. What we are trying to accomplish is to have our receiving inspectors sample parts to determine if the parts have a moisture contamination problem or not. We would then use this information to decide which parts need to be baked prior to being placed into dry storage for use in production. Any comments would be greatly appreciated. Regards, Brad L. Matthies SMT Process Engineer ---------------------------------------------------------------------------- ----- 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 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 ---------------------------------------------------------------------------- ----- --------------------------------------------------------------------------------- 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 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 ---------------------------------------------------------------------------------