Anybodfy hear about "DUT " board? (Device Under Test or called LoadBoard) board with spec. 3mm thickness, 0.25mm drill and this kind of drill must filled with epoxy or filled with gold plating Please let me know what DUT board is for? Thanks johnnie ================== send from ====================== Johnnie Kim SEP CO.,LTD. A.S.K BUILDING 6F, 975-11,YOUNGTONG-DONG PALDAL-KU, SUWON-SI, KYUNGGI-DO,KOREA Phone:+82-(0)31-206-6438 Telefax:+82-(0)31-206-6438 E-mail : [log in to unmask] http://www.sep.co.kr ================================================== -----Original Message----- From: Guenter Grossmann [mailto:[log in to unmask]] Sent: Friday, January 19, 2001 6:15 PM To: [log in to unmask] Subject: [TN] Antw: [TN] Phase transistions in solder joints Sophia - Structure The solder will change its structure during operation: The lead phases are getting coarser, the tin domains don't change much ( I know Werner, we don't fully agree in this ). However, this will also occur at ambient temperature so I wouldn't care about that. - Properties The creep properties of solder are temperature dependent. This means at high temperature the material deforms easier. In this respect one could speak of weakening. This might be a problem if your board is in vertical position and you have heavy components soldered in SMT. But I would consider this rather hypothetical. - Intermetallics Yes they grow. However, the problem of rupture occurs with temperature cycles that are fast enough to bring enough shear stress in the intermetallics to break them. Best regards Guenter Guenter Grossmann Swiss Federal Institute for Materials Testing and Research EMPA Centre for Reliability 8600 Duebendorf Switzerland Phone: xx41 1 823 4279 Fax : xx41 1823 4054 mail: [log in to unmask] ---------------------------------------------------------------------------- ----- 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 ---------------------------------------------------------------------------- ----- --------------------------------------------------------------------------------- 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 ---------------------------------------------------------------------------------