Hi Edwin, see J-STD-001B (has been issued in October 1996), § D-5.1, Sample Size: "A minimum of 10 vehicles shall be tested for each material/process combination. This sample size was calculated by setting a consumer risk at 10% (confidence of 90%). A complete explanation of how this sample size was determined can be found in IPC-TR-467. It is recommended that additional unprocessed vehicles be tested as controls." okydky, so weit - so gut: * for definition of consumer risk ask your QA guy (the propability to miss a failure is 10%). * IPC-TR-467, §5.1: it seems the sample size was so determined in view of intermittend decreasing of the SIR because Electrochemical Migration: §5.1 (or does have other technos other ideas?) * Initial pretest preparation: because during test configuration you have to catch the process-influence (fluxer/solder resist/cleaning process) on the Contamination/SIR. This means you have to exclude other influences (fingerprints, initial contamination of the pcb surface..). For this purpose I would suggest you should clean the samples before the "main-test preparation" according IPC-TM-650, No. 2.6.3, §5.2.5 ... 5.2.10 or IPC-TM-650, No. 2.6.3.3, §5.2. Bernhard > Date: Tue, 30 Nov 1999 08:57:25 -0500 > From: "Louis, Edwin @ CSE" <[log in to unmask]> > Subject: Information Needed > > Does anyone have the telephone number for Contamination Studies > Laboratories > or that of Doug Pauls. And, can anyone tell me in paragraph D-4.3.5.1 of > IPC-J-STD-001a, what the control samples are and what the > sentence,"Additionally,six control boards(three for cleanliness testing > and > three for SIR testing) shall not be processed beyond the initial pretest > preparation" means. What paragraph describes pretest preparation? > What is the pretest preparation process? > ############################################################## TechNet Mail List 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://www.ipc.org/html/forum.htm) for additional information. If you need assistance - contact Gayatri Sardeshpande at [log in to unmask] or 847-509-9700 ext.5365 ##############################################################