Mike, Requarding anular ring, Before getting into the smallest a/r what type of board are you laying out? Standard rigid board with 6/6 line and spacing is using a minimum a/r of approx. .015 over finished hole size. This is also based on the minimum acceptible anular ring on the finished board. The tighter demand placed on the a/r requirement the more costly the board will be. The standard rule I like designers to use is the maximum anular ring for the design allowable, with .020 over the finished holes size preferred. Remember the hole drilled will be approx .005" larger in diameter to allow for the plating in the hole. So, an a/r .015 over finished hole size will be .010 over the drilled hole size, allowing .005" per side of the hole for registration over a panel 18 x24. The tighter the anular ring the more difficult holding the registration will be. Also tear dropping pads with tight anular ring will help hold the registration. Last if a design with an anular ring too small their is a very good chance you will recieve a call from your board manufacturer. Therefore, if you have a questionable design due to manufacturability calling you board manufacturer for minimum requirments and any price changes due to these requirements might be a good idea. ---------- > I have a request from my CAD department on min. annular ring area (i.e. > outside circumference - inside circumference). What is the smallest > annular ring vs hole size used in the industry! Thank you in advance. > > Best Regards, > > Mike Forrester > LeCroy Corp. > [log in to unmask] > > ################################################################ > TechNet E-Mail Forum 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://jefry.ipc.org/forum.htm) for additional > information. > For the technical support contact Dmitriy Sklyar at [log in to unmask] or > 847-509-9700 ext.311 > ################################################################ > > ################################################################ TechNet E-Mail Forum 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://jefry.ipc.org/forum.htm) for additional information. For the technical support contact Dmitriy Sklyar at [log in to unmask] or 847-509-9700 ext.311 ################################################################