I think LCOA did a study of hole wall roughness way back. I might still have a copy somewhere. Or maybe there's some info on LCOA's website www.lcoa.com. geoff layhe > ---------- > From: Dennis Fritz[SMTP:[log in to unmask]] > Reply To: TechNet E-Mail Forum.;[log in to unmask] > Sent: 04 August 2000 04:06 > To: [log in to unmask] > Subject: Re: [TN] Hole wall roughness > > Couple of comments on hole wall roughness: > > 1. Seems I remember a systematic measurement of roughness, using cross > section photos to measure the actual lenghth of the dielectric/copper > plate > interface with something like a map maker uses to estimate length of road > on > a map. This length is divided by the laminate thickness to get a number > bigger than 1.0. A 1.03 hole would be smoother than a 1.08 hole. Think > this came from a big study of drill parameters - entry material, feeds and > speeds, number of hits, etc. Anyone got the details of quantifying > "roughness" from that study? > > 2. Holes are rougher when measured at a 45 degree angle to the weave > directions, than the normal cross sections measured with the weave. Try > it - > cross section holes at the !:30/7:30 and 4:30/10:30 locations rather than > 6:00/12:00 and 3:00/9:00. Reason - the drill is cutting the glass bundles > on > an angle there, and tears the glass bundle worse than perpendicular bundle > cuts > > Denny Fritz > MacDermid. > > ############################################################## > 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. > If you need assistance - contact Keach Sasamori at [log in to unmask] or > 847-509-9700 ext.5315 > ############################################################## > ############################################################## 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. If you need assistance - contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 ##############################################################