Jorge, Why don't you try a water soluble masking on the via's? That is what we do and it works for us. After cleaning, the holes are ready for test. The Masking is: Wondermask by Techspray P/N 2204-8SQ. Yes, this adds one more step to the process but saves a lot of touchup later. I hope this info is of value. Patty Olinger Manufacturing Engineer Projects Unlimited (937)918-2267 [log in to unmask] -----Original Message----- From: Jorge Rodriguez [mailto:[log in to unmask]] Sent: Friday, January 11, 2002 2:10 PM To: [log in to unmask] Subject: [TN] Solder Balls on Wave Solder Technetters, My company is having a solder ball problem on the wave solder. The issue is primarily caused by overly large un-masked vias on both sides. The via diameter is 25 mils with an annular ring of 25 mils on a .062" board. On the wave solder process, the flux gets entrapped inside the vias and no matter what we do on the pre-heating section there still flux remaining inside that causes the solder to explode into tiny solder balls when it gets to the laminar section of the wave, like a volcano effect on the component side. These boards have also a good amount of the same vias under fine pitch QFP devices , this narrows our process window if we want to heat the board even more. Heating the board more on the preheaters to resolve the solder ball problem leads on re-reflowing of the leads of those devices and quality problems as a result of that, the QFP pins pop up and become un-soldered. The customer does not want to use smaller vias or get them masked off since vias are used for test and rework purposes, they want to be able to insert wires inside the vias in case they need to change the board configuration. Any ideas on what to do with the wave process to resolve this issue? Any ideas would be greatly appreciated. Jorge Rodriguez Process Engineer Varian Electronics Manufacturing 615 South River Drive Tempe, AZ 85281 Phone: (480) 968-6790 X 4258 Fax: (480) 829-4000 E-mail: [log in to unmask] ------------------------------------------------------------------------ --------- Technet Mail List provided as a free service by IPC using LISTSERV 1.8d To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL To recieve ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail Archives Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 ------------------------------------------------------------------------ --------- --------------------------------------------------------------------------------- Technet Mail List provided as a free service by IPC using LISTSERV 1.8d To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL To recieve ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail Archives Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 ---------------------------------------------------------------------------------