At the risk of starting an uproar, I'd like to mention a couple of things we've heard. I've had board vendors remove the dead pads without telling me about it, in which case the boards don't match my artwork any more. Deffinately a no-no. Some board vendors say they don't want the pads to spin out when they perform their drilling oberation while other board vendors suggest the first vendor use sharp drills. I've also heard that the internal pad may help the adhesion, and possibly strengthen the plating in the hole. I'd really like to have the IPC test this out and document the resusts so this question can be put to rest. Maybe they have already done so, but I haven't been able to find any documentation about it yet. It basically boils down to a matter of preference and personal choice at this point, I believe. I'll expect to see a lot of response to this but I'd really like to see some documented results. Larry Campbell Supervisor, PWB BFGoodrich Avionics Systems [log in to unmask] >>> Per Viklund <[log in to unmask]> 01/19/98 02:48am >>> Hi David, I don't have any figures but this is common practice with all the companies I work with. But then, I MAY have a different definition of a dead pad. I mean that the pad is dead on all inner layers that it does not have a connecting wire on. On outer layers, I've never seen it but if a pad is unconnected in an inner layer, it's safe to remove it. For plane layers, it's slightly different since it's either a matter of connection or no connection where the 'no connection' is a form of clearance rule. However, you would not like to remove the pad completely -just decrease the size. That will ease routing on that layer if your cad tool supports this dynamically. You will need a small pad to prevent plating chemicals to go into the lamination between the layers. -How big of a risk it is to get problems with plating chemicals if you do remove the pad completely, I don't now. Regards Per Viklund Dansk Data Elektronik AS mailto:[log in to unmask] http://www.dde.dk/eda/ David Backen wrote: > > We are looking for data, papers or personal experience with regards to > dead pad removal (both signal and plane layers) and the impact on hole > wall reliability. > > Board type: 4 - 14 layers, 20 - 100 mils thick, FR-4 material and other > material types if available. > > I appreciate any information you may have. > > Regards, > Dave Backen > [log in to unmask] ############################################################## TechNet Mail List 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 web site (http://www.ipc.org/html/forum.htm) for additional information. For the technical support contact Dmitriy Sklyar at [log in to unmask] or 847-509-9700 ext.311 ############################################################## ############################################################## TechNet Mail List 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 web site (http://www.ipc.org/html/forum.htm) for additional information. For the technical support contact Dmitriy Sklyar at [log in to unmask] or 847-509-9700 ext.311 ##############################################################