To add my input to the argument: Keeping the non-functional lands in the board does decrease the Z-axis expansion at soldering temperatures by about 10-30%, mainly, because above the Tg the Z-Axis expansion is great for the resin systems, but copper remains the same. As mentioned, the difference in expansion will make a difference on whether you have lifted lands or not after HASL or soldering, I have seen this demonstrated several times . Of course, the boards with the thinner dielectric benefit the most. The hole-wall pullaway, if this is a concern, is also decreased and many people subjected to the 40% rule will now pass this requirement if non funtional lands are retained . The fabricators, of course, want them removed as they increase the probability of shorts or other etching defects and removing them will increase yield. Phil Hinton [log in to unmask] *************************************************************************** * TechNet mail list is provided as a service by IPC using SmartList v3.05 * *************************************************************************** * To unsubscribe from this list at any time, send a message to: * * [log in to unmask] with <subject: unsubscribe> and no text. * ***************************************************************************