Part coating flowing into solder joints| 22 October, 2010
I am having a horrible time with the square radial lead capacitors (thru hole components) and the part coating flowing into the solder joint. These are Class 3 products. When we run them through the wave solder machine, the solder travels up the lead and draws the part coating into the solder joint, which violates IPC class 3. I can't kink the leads because I am only allowewd 0.020" off the board surface. I am using some saw tooth styles which put the cap and lead joint further away, but still draws the coating. The virgin components do have some coating on the leads, prior to soldering, but nothing I can reject against the manufacturer. We've tried 2 manufactures, Kemet and AVX. Any suggestions on how to prevent this?