According to Coombs' Printed Circuits Handbook, 4ed., "...there is almost a linear relationship between board cost and layer count." (sec 1.6.4., p.1.19). You might also check out chapter 7 of the same reference. And, for what it's worth TMRC '96, says the avg. multilayer PWB was $18.20. J.Felts -----Original Message----- From: Olson, Jack C [SMTP:[log in to unmask]] Sent: Thursday, May 14, 1998 4:53 PM To: [log in to unmask] Subject: Re: [DC] No. of layers Vs. cost Well, I was really hoping to see a few answers on this one, even though it would be difficult to make a predictable rule or guideline about it. (did you get any answers privately?) Anyway, I can tell you this much, maybe it will help: All of my experience with quoting/purchasing boards has been for fast turn prototypes, never production. After about 40-50 orders I noticed a general trend that the layer count was related to the cost in a very simple way. That is, that the layer count was proprtional to the cost almost directly, so that a 4 layer board would cost 4/2 as much as a 2 layer board, but adding two MORE layers, 6 layer board would only cost 6/4 as much as a 4 layer board, or 1.5 times as much. If you can shave two layers off a 12 layer board, you will pay only 10/12 as much for it. OK, take that with a grain of salt, and its only a ROUGH estimate, but I got to where I could make a reasonable prediction using that rule. Good Luck, Jack -----Original Message----- From: Gagrani, Kishore [SMTP:[log in to unmask]] I understand that more no. of layers would increase the cost of PCB, but how is this function related ? Is there any formula (certainly will have many no. of variables) which can be applied to figure this out ? ################################################################ DesignerCouncil 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 DesignerCouncil <your full name> To unsubscribe: SIGNOFF DesignerCouncil ################################################################ Please visit IPC web site (http://jefry.ipc.org/forum.htm) for additional information. For technical support contact Hugo Scaramuzza at [log in to unmask] or 847-509-9700 ext.312 ################################################################