Stephen, Have you attached thermocouples around the QFP to verify that the QFP is: A) Reaching Liquidous? B) Is at Liquidous for a long enough period of time? I have had grainy solder joints and found that I was not at liquidous for a long enough period of time for complete reflow of all of the solder joints. It was on a very dense assembly and the problem was more in the center of the assembly. Just curious. I have used aluminum fixtures for assembly processes and have never had an issue with contamination. Good Luck, Kathy Palumbo > -----Original Message----- > From: Stephen Bonaccorsi [SMTP:[log in to unmask]] > Sent: Thursday, April 01, 1999 3:34 AM > To: [log in to unmask] > Subject: [TN] GRAINY JOINTS > > Hello Everybody > > I am currently reflowing with a convection oven (No Nitrogen). A board > that has perfect solder joints apart from grainy solder joints on one > particular component (QFP). Other components on the board resistors/caps > and components of similar size are fine. > Therefore I don't think there is a problem with the oven profile. > > This component does go through an extra process before hand. > Initially the component is supplied with no pins (Very long story, > don't ask!) > These are attached to the body of the component using an aluminum > jig/fixture to hold them in place. The legs are supplied > pre-soldered. > RMA flux is then applied (liberally) to the area to be soldered. > The jigs with the components are then placed through a vapour phase oven > for soldering . > > Is it possible that the legs are being contaminated by Aluminum or its > oxide from the jig/fixture, if the flux is reacting the Aluminum. > > Would aluminum contamination give grainy joints? > What else can cause grainy joints? > > Thanks for any help > > Stephen Bonaccorsi > > ################################################################ > TechNet E-Mail Forum 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's web site (http://www.ipc.org) "On-Line Services" > section for additional information. > For technical support contact Hugo Scaramuzza at [log in to unmask] or > 847-509-9700 ext.312 > ################################################################ ################################################################ TechNet E-Mail Forum 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's web site (http://www.ipc.org) "On-Line Services" section for additional information. For technical support contact Hugo Scaramuzza at [log in to unmask] or 847-509-9700 ext.312 ################################################################