Steve, It's exactly VME Backplanes that we use press-fits for. They're about the same number of layers, but much thicker for rigidity (0.250" !) We have a bunch of small discretes on the underside and some SOIC16's etc. Really don't envy you the BGA RAM chips with that thickness of board and press-fit conns. Oh! The Flexure! I hope your board's physical support is really good so you don't pop the BGA's off during pressing (I presume you're fitting components first, as I don't know what thermal profile temperatures will do to the connector pin: hole barrel interfacing.Certainly the pins will expand and the hole diameters will contract with temperature and the pin corners will cut even more into the plating. Then when they cool again ....) Good luck, Buddy! Peter [log in to unmask] 28/10/2002 09:01 AM To: DUNCAN Peter/Asst Prin Engr/ST Aero/ST Group@ST Domain, [log in to unmask] cc: Subject: Re: [TN] Press fit connectors... Thanks Peter! I'm about to build a VME card that's density is beyond belief, that utilizes press-fit connectors. When Jack suggested that they be soldered as a standard practice, I almost had a coronary!!! Just to let you know, we're talking about a 16-layer, .062" thick board, with a of bunch .020"-pitch components on the bottom, along with BGA RAM on the bottom... No wave at all...so Jack, do we hand solder this stuff? Remember, we're talking 16-layers... -Steve Gregory- Hi, Steve, Press fit connectors are just that - press fit - and they are designed not to be soldered. The quality, diameter and tolerance of the plated hole into which they are pressed is critical, though, for successful press fitting, but you must know all this. If you then solder the pins you'll have the devil's own job getting them out again, quite apart from not having enough clearance in most cases At least for class 3 boards, wherever I've been, we mechanically support them as well - nuts and bolts, though I've also seen them just pressed with no mechanical support, and they've worked fine, especially high pin-count conns with plenty of insertion/extraction force. Check out the Harwin .com site for info. If incompetence is being sought, I suggest that your customer review their requirements, assumptions, source information, etc., before slinging mud at you. Peter [This e-mail is confidential and may also be privileged. If you are not the intended recipient, please delete it and notify us immediately; you should not copy or use it for any purpose, nor disclose its contents to any other person. Thank you.] --------------------------------------------------- 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 -----------------------------------------------------