just a quick note on lasing...i found it, once dialed in, to be a very good process. the biggest deal besides ablating the holes is plating them...sounds like an old song now. it took me less than a week to work up a very wide process window for 1080 fr-4 with an nd/yag UV laser. everything looked great on the microsections but we found we had about .5% fall out due to plating voids in the finished boards...a difficult number to really work with, too slim for easy failure analysis yet one or two opens per board didn't work...used really low amps and a couple of 'cheats' at electroless (metalization) to get the job out...and ended up going to complex waveform reverse pulse plating...which made things more or less a cake-walk...bottom line is that if i was to bring laser drilling in house again i'd sub-contract the drilling (that is hold off on the rather substantial capitol investment in a laser via machine) until i had the rest of my processes dialed in...registration on n-1 layers...coordinating the registration between the mechanical hole grid and the micro-via placement...and of course reliable process....one of the more 'holistic' processes i've worked with...everything needs to work together, you can't just ship out panels for drilling and process them the same old way... might as well throw in my $.02 worth on your grinding idea....i'm a little concerned about the integrity of the 'knees' of the plated barrels...it's always nice to see an even coating of rich, thick, well leveled copper going from the surface all the way into the barrel of the hole...interrupting this, then re-plating over top -might- not give you as solid a 'knee' and with board expansion from z-axis CTE mismatches so common in fr-4 construction, you might see a higher than normal drop out well after the fabrication fact...i'd do some fairly aggressive solder floats, at least 5x 10 seconds in a pot of 550 degrees and look for any signs of failure...to ensure that there are no long-term reliability issuesthat being said, i've plated, filled and ground lots of blind vias without too many reliability issues in avionics applications...so it's do-able...just so you're aware of potential pit-falls really... good luck...sounds like an exciting project ian --------------------------------------------------------------------------------- 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 the following message: SET Technet NOMAIL 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 ---------------------------------------------------------------------------------