Good reply but I think he means space not place. > -----Original Message----- > From: TechNet [mailto:[log in to unmask]] On Behalf Of Matthias Mansfeld > Sent: Monday, January 06, 2003 3:34 PM > To: [log in to unmask] > Subject: Re: [TN] SM-782A > > > On 6 Jan 2003 at 12:25, Black, Paul wrote: > > > My company is in the process of relayout of a board, and we > are trying > > to use SM-782A for component layout. However, we are seeing > a number > > of discrepancies between the recommended layout from the component > > manufacturer and the SM-782A standard. The differences include pad > > length and width, and distances between pads and pad rows. > Does anyone > > have experience with this problem, and what is your recommendation? > > > > Thanks in advance, > > Paul Black > > Manufacturing Engineer > > Kronos Incorporated > > The IPC standard tries to define optimum footprints for best > process safety for the worst case sum of tolerances (means it > should fit with nearly every board shop and every assembly house). > > Footprint recommendations from component manufacturers may > base on own tests under standard or specific conditions and > can save place and trouble (good example are the great > Philips footprint guidelines which need often much less place > than IPC but need a bit more precise placement equipment and > sometimes a few prototype runs to optimize the soldering process) > > Or they result on nothing more than untested own thumb rules > with no scientific or experience-based justification. That's > worst case. > > The best idea is to check critical dimensions against IPC, > against good-known other recommendations (like Philips) and, > most important against the experiences of your favourite > assembly house. > > HTH, Regards > -- > Matthias Mansfeld Elektronik > * Printed Circuit Board Design and Assembly > Am Langhoelzl 11, D-85540 Haar, GERMANY > Phone: +49-89-4620 0937, Fax: +49-89-4620 0938 > E-Mail: [log in to unmask] > Internet: http://www.mansfeld-elektronik.de > > --------------------------------------------------- > Technet Mail List provided as a free service by IPC using > LISTSERV 1.8e 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 or > (re-start) delivery of Technet send e-mail to > [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE > mailing per day of all the posts: send e-mail to > [log in to unmask]: SET Technet Digest Search the archives of > previous posts at: http://listserv.ipc.org/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 > ----------------------------------------------------- > --------------------------------------------------- Technet Mail List provided as a free service by IPC using LISTSERV 1.8e 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 or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/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 -----------------------------------------------------