Hi Matthew No problems (I was surprised too) here . Perhaps few quartz IR bars would help you to boost the top ; seems the plcc's drains too much , the heat flow around square is bit sluggish . I found convection with touch of IR (only if you need it) ideal combination . Paul >---------- >From: Matthew Park[SMTP:[log in to unmask]] >Sent: Wednesday, 7 January 1998 9:29 >To: [log in to unmask] >Subject: Re: [TN] Lead Solderability - second reflow -Reply > >Paul, > >Are you saying "maintaining two different temperatures" for >top and bottom sides during the second reflow? > >I remember testing reflow temp profiles with the bottom >side reflow zone set at 20'c to 30'c lower than the top side >reflow zone. Since the board temp on the bottom side is >about 5 to 10'c cooler, it works quite well for preventing >components falling off, but once in a blue moon, causes >unsoldered joints for top side large smt components like >PLCC's. > >Matthew > >>>> Paul Klasek <[log in to unmask]> January 6, >1998 1:47 pm >>> >Hi Krishna >Apart from what Matthew recommends, if you do not want to >go through >glue process and do not want to reflow base again and have >to keep chips >on base as well at the same time ; >with convection you have an option of "chilled" base air feed >with up to >a 25C temp. difference , >that would hold you anything. >Tested & proven , original equipment or pending your oven >perhaps a mod. >Without sparking commercials , write me back on my >address, I'd have to >refer you to a specific solution . > >See you Paul > >>---------- >>From: Krishna >Kalyan[SMTP:[log in to unmask]] >>Sent: Wednesday, 7 January 1998 2:15 >>To: [log in to unmask] >>Subject: [TN] Lead Soderability - second reflow >> >>Hello : >> >> Happy New Year to all of you. >> >> I am a process engineer trying to resolve the falling of a >bottom side >>surface mount component during second pass of forced >convection reflow. >>I am beginning to feel that the solderability of the >component leads is >>getting reduced after the first pass of reflow and that is >causing the >>part to fall. If any of you have had similar experiences, could >you >>please share ? Your suggestions are welcome. >> >>Krishna Kalyan >> >> >>______________________________________________________ >>Get Your Private, Free Email at http://www.hotmail.com >> >>############################################################## >>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. >>For the technical support contact Dmitriy Sklyar at >[log in to unmask] or >>847-509-9700 ext.311 >>############################################################## >> > >############################################################## >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. >For the technical support contact Dmitriy Sklyar at >[log in to unmask] or 847-509-9700 ext.311 >############################################################## > >############################################################## >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. >For the technical support contact Dmitriy Sklyar at [log in to unmask] or >847-509-9700 ext.311 >############################################################## > ############################################################## 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. 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