Pb-Free Loctite 3508 -----Original Message----- From: Guy Ramsey [mailto:[log in to unmask]] Sent: Tuesday, December 09, 2014 4:08 PM To: 'TechNet E-Mail Forum'; 'David Hillman' Subject: RE: [TN] BGA Reflow Issue Loctite makes a BGA corner bonder that allow the balls to melt then cures. And it is reworkable. For SnPb it is Loctite 3515. I don't remember the Pb-Free part number. Guy -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of David Hillman Sent: Tuesday, December 09, 2014 3:47 PM To: [log in to unmask] Subject: Re: [TN] BGA Reflow Issue Hi Ioan! Yep, its falling off as we have had a couple of them stay in the reflow oven for some additional "hot" time! A good friend and TechNet lurker, Fritz Byle of Astronautics, made me a Excel program many years ago that calculates & compares BGA weight to surface tension so I can usually predict if I am going to have a problem. This BGA in question is one of those that is "right on the edge of the cliff" in terms of holding on. We have looked at reflow profile changes but I just can't convince the Laws of Physics to temporarily go away for the BGA so I am working "Plan B" with the temporary mask material until we can revise the assembly and move the BGA to process side two. Dave On Tue, Dec 9, 2014 at 2:11 PM, Ioan TEMPEA <[log in to unmask]> wrote: > Hi Dave, > > Just out of curiosity, have you seen the BGA falling or you are just > afraid it might? > > Because I have ran thousands of BGAs in second reflow (ceramic, metal > top, name it), on bottom side, with absolutely no BGA loss. The balls > would keep their collapsed aspect, even though they might be slightly > stretched, but this is bound to improve compliance, hence long term reliability. > > Best regards, > > Ioan Tempea > MDA Corporation > > > > -----Original Message----- > > From: TechNet [mailto:[log in to unmask]] On Behalf Of David Hillman > > Sent: Tuesday, December 09, 2014 8:42 AM > > To: [log in to unmask] > > Subject: [TN] BGA Reflow Issue > > > > Hi gang - looking for an adhesive suggestion. I have an assembly in > > which a heavy BGA was accidently located on process side one > > (bottom) so that when we reflow process side two (top) the BGA is > > doing its best to fall off. > > Unfortunately I can't reverse my process order for a couple of > > reasons so I am looking for a temporary fix until I can get the > > assembly revised. I was thinking of using some type of adhesive to > > temporarily hold the BGA in place during reflow - tack down the > > corners sort of action. Does anyone have any adhesive (ideally > > temporary, water > > washable/removable) suggestions I can investigate? > > > > TIA > > > > Dave Hillman > > Rockwell Collins > > [log in to unmask] > > ______________________________________________________________________ > This email has been scanned by the Symantec Email Security.cloud service. > For more information please contact helpdesk at x2960 or > [log in to unmask] > ______________________________________________________________________ > ______________________________________________________________________ This email has been scanned by the Symantec Email Security.cloud service. For more information please contact helpdesk at x2960 or [log in to unmask] ______________________________________________________________________ ______________________________________________________________________ This email has been scanned by the Symantec Email Security.cloud service. For more information please contact helpdesk at x2960 or [log in to unmask] ______________________________________________________________________