Hello Elizabeth: There are lots of things to investigate to get to the bottom of this issue. 1. Board design. Orientation of component relative to the direction of travel over the solder pot. 2. Solder contamination. Contaminated solder will have a lower viscosity than new solder and it could be the sluggishness which prevents it from peeling off the bottom of the board. 3. Incline of the conveyor. The conveyor should be incline 5 to 6 degrees to help the solder peel off the bottom of the board. 4. Uncured solder mask could also be a problem. Check the hardness of the mask at soldering temperatures. 5. The no clean flux is not providing enough flux to help the solder peel off the bottom of the board. For experimental purpose try a different type of flux, perhaps something with a higher solid content. 6. Check the speed of the conveyor. You should be in the solder approximately 1 to 2.3 seconds to get acceptable soldering. 7. Check to see if the board warps going over the wave. This will cause the board to run deeper in the wave thereby changing the effective conveyor speed, and it will impact the way the solder peels off the bottom side of the board. If you want to talk about this, please give me a call. 1 800 64 EPTAC Good Luck Leo Lambert Technical Director EPTAC Corp. Check out our Web page at www.eptac.com At 07:36 AM 4/23/97 -0400, Elizabeth Falk wrote: >Dear Technet, >I have a customer who is reporting bridging on the solder side of the board >after wave soldering. I have seen the boards, and they look quite messy, >with solder sticking to the mask as well as between component leads and >pads. The mask itself is adhering nicely. The mask is PC501 from Haven, >with C101 hardener. This was recently discontinued by MacDermid and picked >up by Haven. The flux is no clean, ENFLUX NCF-8660, and is under pressure >with nitrogen. The wave itself is at 500 degrees F, with preheats set to >get the board to 210 to 220 degrees F when it hits the wave. The same >design board with LPI ran fine, so I do not suspect a problem in another >area of the process. > >No other customers are reporting this problem, and I am at a loss as to >where to investigate further. The customer is not happy, and wants a >resolution today! If anyone has any insights, please let me know. > >Thanks, >Elizabeth Falk >Process Engineer, Beaverbrook Circuits > >*************************************************************************** >* TechNet mail list is provided as a service by IPC using SmartList v3.05 * >*************************************************************************** >* To subscribe/unsubscribe send a message <to: [log in to unmask]> * >* with <subject: subscribe/unsubscribe> and no text in the body. * >*************************************************************************** >* If you are having a problem with the IPC TechNet forum please contact * >* Dmitriy Sklyar at 847-509-9700 ext. 311 or email at [log in to unmask] * >*************************************************************************** > > > *************************************************************************** * TechNet mail list is provided as a service by IPC using SmartList v3.05 * *************************************************************************** * To subscribe/unsubscribe send a message <to: [log in to unmask]> * * with <subject: subscribe/unsubscribe> and no text in the body. * *************************************************************************** * If you are having a problem with the IPC TechNet forum please contact * * Dmitriy Sklyar at 847-509-9700 ext. 311 or email at [log in to unmask] * ***************************************************************************