Dennis, From one of the old guys from when the 741 Op-Amp was a new marvelous invention. If your talking about through hole boards, then putting all the components on the "top" side is the most cost effective. If your talking surface mount, then it is just a matter of the added steps to place components on the top and bottom and then reflow the solder. Regards, Phil Nutting -----Original Message----- From: Dennis Ward [mailto:[log in to unmask]] Sent: Friday, March 17, 2000 6:54 AM To: [log in to unmask] Subject: [TN] One side vs Both side Good morning everyone, Question for all you manufacturing gurus. Is there a significant advantage, cost wise, to keeping all the components on the top side of the board versus placing components on both sides? Now I do know that they are some NRE cost, but is it significant? In the past I was taught you should try to keep every thing on top. But it seems that high density double side boards are very common. There doesn't seem to be as much emphasize on consolidating all the components on the top side. As an example if you quoted two boards - all things being equal except that one was populated on the top and the second board was populated on both sides what would be the cost difference (if any)? The reason I ask is that I am laying out a board that I may be able to squeeze everything on top. However I'm tempted to just throw discretes on the bottom of the board. The engineer asked what was I going to do. I told him that I'd try to keep everything on top. He then asked "why"? I answered it would be easier to manufacture, inspect, debug, eliminate some manufacturing steps and eliminate some cost. But I started thinking and wondered if my thinking was backwards and these concerns are negated with the advance of technology. Anyway, any advice would be greatly appreciated. Also I would like to take a moment and thank everyone for their particpation on this forum. It has proved extremely useful for me personally. Enough so that a few strings of humor well not affect my judgement as to the value of this forum. Actually I enjoy hearing some of the "old timers" discuss the days of tape and exact-o knives - personally never had the pleasure. Thanks Dennis Ward Net to Net Technologies, Inc. 603 427-0600 [log in to unmask] http://www.nettonettech.com ############################################################## 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 ##############################################################