Electronics Forum | Fri Apr 23 13:31:20 EDT 2004 | russ
The toes of leaded devices are problematic in fillet formation. A lot of the time they have the copper from the lead exposed so it becomes oxidized and won't readily take solder. Normally this is of no concern if the heel and side fillets are forme
Electronics Forum | Mon Nov 12 01:18:29 EST 2007 | sin4d
Hi, ALL I experience some QFP with wetting issue on the heel of the lead. There is no fillet wetting on the heel which causes reject bt the customer, but not all the QFP. Could anyone pls help what is the causes of this problem, it is due to oxidati
Electronics Forum | Mon Nov 12 10:57:23 EST 2007 | chineechooze
i will supply dah 3d chart to sol the problem foryou
Electronics Forum | Tue Nov 13 22:20:50 EST 2007 | davef
We'd add poor thermal recipe development, focusing on some QPF but not others that may a have a peculiar plating that requires extended time above liquidus.
Electronics Forum | Mon Nov 12 19:47:33 EST 2007 | sin4d
Hi, Thanks. Waitng for your reponse. BTW, if I were to perform a test as below will this give me some result to indicate if the component is defective. 1) Print solder paste on plain PCB without copper track. 2) Mount the QFP & reflow 3) If the sol
Electronics Forum | Mon Nov 12 09:22:41 EST 2007 | russ
Could be any one of the 3 you mentioned, need some details here, do you really think we can answer this question as it is? Now for your issue, what is the make up of the lead itself on the part? what is the reflow profile at this part? what is
Electronics Forum | Tue Apr 11 10:30:46 EDT 2000 | Jeremy Smith
I am having a problem with some joints on a 100 pin pqfp and few different soics on one particular board. When viewed a 8x with a "Mantis" inspection scope the joints look as though they wetted to the ic leg but when probed the leg will pop loose.
Electronics Forum | Tue Apr 06 09:50:58 EDT 1999 | Justin Medernach
| Does anybody put QFP's on the backsides of boards? Can they be reflowed without falling off? Do you use adhesive? | I use a double sided reflow process all day, everyday. I've hung QFP240s with embedded heat sinks and they don't fall off. Yei
Electronics Forum | Tue Apr 11 16:42:56 EDT 2000 | Chad Notebaert
I�m thinking �Poor intermatallic� It could be a few things. Lets start at the beginning. -Is your paste a 63/37 mixture? -Have you monitored you screen printing, Verify Solder deposition, Are you getting enough paste? -You say the solder looks like i
Electronics Forum | Thu Dec 01 14:42:57 EST 2005 | Amol Kane
my first thought was that too, but all the other components on tha board have reflowed properly. I have tow test boards, one with Imm Sn and other with Imm AG. on both these boards only the QFP has this solder phenemenon
