Electronics Forum | Tue Mar 15 10:44:42 EST 2005 | jdengler
-If the aperture volume is the same, there will be more solder on the HASL finish joint due to the solder already present on the pad. This difference is not usually enough to cause insufficiant solder volume but will "look different". Sometimes an
Electronics Forum | Wed Mar 16 08:06:52 EST 2005 | zsolt
Grant is right, also for us was the easiest solution to us custom pallets. But you should also try to tweak preheat zones settings. The flux manufacturer should give you some basic temperatures where the flux gets activated. Also it is worth to make
Electronics Forum | Wed Mar 16 09:34:12 EST 2005 | patrickbruneel
Here's a previous thread that can give you guidance http://www.smtnet.com//forums/index.cfm?fuseaction=view_thread&CFApp=1&Thread_ID=6947&#Message27732 For machine settings this link may help http://www.interfluxusa.com/Technical/technical-info.htm
Electronics Forum | Wed Mar 16 09:48:44 EST 2005 | jdengler
I'm with Russ on this one. Had a similar problem with a flex circuit that used gold contacts into a ZIF connector on a ridged PCB. After may test I finally convinced the customer to do some test on the ZIF connector. The end result was flux contam
Electronics Forum | Thu Mar 17 22:47:29 EST 2005 | davef
That would be our first guess, also. Get the stuff analyzed to be sure. Another clue is if the white stuff disappears when you hit it with hot air from a rework station. The hot air is activate the flux. Good troubleshooting tool, but you're subj
Electronics Forum | Thu Mar 17 09:30:59 EST 2005 | John S
We are moving into using fine pitch components in a double sided reflow process. In one of our test runs, we noted that some of the QFP's would move while reflowed on the bottom on the second pass and become defective. Is this being done widely wit
Electronics Forum | Thu Mar 17 11:07:08 EST 2005 | Dougs
I'd agree with Justin, we do double sided reflow on most of our boards with fine pitch QFP's both sides, you do have a problem somewhere else, what size is you board? Is it warping slightly? What kind of oven are you using? Is it convection? fans
Electronics Forum | Tue Mar 22 12:04:31 EST 2005 | John S
Thanks for the advice. In this scenario we are designing our own product. Currently we are building at a prototype level with no appreciable wait between reflow passes. The part in question is a 64 pin QFP. We use a BTU VIP 98 with edge conveyor.
Electronics Forum | Mon Mar 21 22:02:32 EST 2005 | dlkearns1
I'd say you already have some documentation, from the customer requirements, eh? I'd also say that regarless of any "standard", if your customer wants xxmils, give it to them, unless of course you'll have to go "above and beyond" what you think is re
Electronics Forum | Wed Mar 30 16:52:41 EST 2005 | chunks
Someone sells the T-couples that are in a rigid tube and the base attaches to the edge of the bord. They have an adjustment nut on em you can adjust to spring load the T-couple on the are you need. They do produce a wavey profile from the part expa
