Am Montag, den 16.02.2009, 18:53 +0000 schrieb Kai-Martin Knaak: > > Some remarks: > > * 4 Layers will take 12 working days minimum, plus what ever it takes for > fedex to ship from china. If you don't register for "open account" > payment needs to be confirmed before production time begins. >
Yes, boards from china will take some time. > * Shipping and customs and EUSt have to be added on top of the quoted > price. > Yes, but total costs are still not bad. If I remember correctly: Four boards, 4 layer, each 26cm * 32cm will give total something about 1000 Dollar. The only company which I aware of here in Germany which is not much more expensive is http://www.microcirtec.de Large quantities are really cheap at pcbcart, so I think it is a good idea to try them. > * There is a maximum number of holes. (300 for my 100x100mm test case) > I think this is no problem, most people use at least some SMD. > * Design rules are modestly aggressive: > minimum drill = 0.4 mm > minimum track width, minimum spacing = 0.2 mm > minimum annular ring = 0.25 mm > My preferred fab offers about 0.75 times these values as standard. > > * Poor english on the webpage. E.g: "For small quantity, if by air the > extra cost will make it not save" (no full stop). > My english is poor also -- perfect fit :-) I think their parameters are not too bad, and I think they can do better, for more money. (And I think drill is 0.3mm without additional costs, think I have seen it...) > > > I think they have no information for impedance control on their page > > There is an item "impedance control" in their quote. I'd guess, this > could be set this to some other value on request. > I have seen this, but do not understand it. I have asked by email some months ago, and got only a very short reply: >Hi Mr. Salewski, >Thanks for your suggestion, we are considering improving our homepage. >Regarding to your question, please see follows: >Trace width: 8.5mil, 1oz copper, 0.12/1.13/0.12 for 50ohm impedance. >Best regards Not much. I guess that I will get 50 Ohm impedance for traces on outer layers of 4 layer board if trace width is 8.5 mil. Hope that I really will get this. Best regards Stefan Salewski _______________________________________________ geda-user mailing list [email protected] http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
