Hi Don, We used to preheat our board to 100degC, be sure you measure the temperature at the board not the preheater and use a Metcal 725 tip for solid plane. It works well on our 12 layers board with 4 solid plane layers. Regards Yak Peng Don_well wrote: > Hi all > > As we know hand soldering PTH component is difficult on a > tens-layer boards because of high heat sink.The solder volume filling > level is always less than 50%. Could you please give me any ideas to > settle this problems.Below is only for referrence. > > 1 Preheat the board about 100 degrees before rework. > > 2 Design a enlarged pad before manufacture. > > 3 >=25% solder level is acceptable. > > Thanks for your advice. > > B.Regards > > Don > > Huawei Tech Ltd --------------------------------------------------- Technet Mail List provided as a free service by IPC using LISTSERV 1.8e 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 or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/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 -----------------------------------------------------