Hi Kelly, 'Wet greetings' from your old home town of San Diego... :) The rain finally stopped today... wow... what a storm! Your comments are right on, and in addition, I just wanted to point out there is another problem with specifying the material as just 'FR4'... You could end up receiving any of a number of different variations of the material and still classify it as 'FR4'... The less clarity you put in the notes, the less criteria your QC inspector has to reject material that is undesirable... What if the environment that this board must survive in is 160 DEG C? Let's say the manufacturer reads the fab drawing note that says ".062 FR4"... He goes and pulls standard FR4 material off the self and makes the 100 board order and ships it... You get the boards and put the 110DegC Tg FR4 material in your product and it fails in test because the material was heated beyond the glass transition temperature it was designed to withstand and expanded in the z-axis rapidly cracking all the barrels of the vias in your board... You can't reject the lot of boards now, they were built to your drawing... you just bought them. Now the vendor COULD HAVE shipped you 180DegC Tg FR4 material... and you would never have had the issue. The value of properly defined notes on the fab drawing is great. It protects your company... and it protects the manufacturer as well from supplying you with material that will not perform to your needs. Then he doesn't have to guess what you *really* mean by 'FR4'. This is a good thing... Best regards, Bill Brooks - KG6VVP PCB Design Engineer , C.I.D.+, C.I.I. Tel: (760)597-1500 Ext 3772 Fax: (760)597-1510 e-mail:[log in to unmask] http://www.dtwc.com http://pcbwizards.com -----Original Message----- From: Dack.Kelly [mailto:[log in to unmask]] Sent: Wednesday, January 12, 2005 8:42 AM To: [log in to unmask] Subject: Re: [DC] Greetings Gary, With regards to quality problems, if everyone in the design and mfg and Q.C. chain has done their job right, you shouldn't have to expect any. Hopefully, this is the case. If the fabrication drawing is calling for .062 FR4 copper clad and nothing more, here are some issues to consider depending PERFORMANCE CONSTRAINTS of the design: (1) .062 CC commonly infers an off-the-shelf "stock" material which will be processed into a two-sided design. If this is the case, go to (2) If not, go to (A) (2) "Copper Clad" might be a little vague if this design has any current carrying constraints. If this design has no current carrying capacity req's over 1amp, check to make sure that min trace width is >/= to ~.010 [.25] Check to make sure that the copper clad is at least 1/2oz. It will be plated up another ~1oz during processing. Go to (3) (3) Coordinate a manufacturability review with your contract assembly vendor. They will be an invaluable source of information. They will require the raw data from the design - the design database. They will get back to you with a detailed set of issues, if any. If there are issues, cycle them back thru the EE. Make sure that the issues are addressed in the source design database. Often, CM's offer to just fix the problem. If this happens, it is sure to crop up again in another iteration of the design as it is re-output from the source. (A) If this is a multi-layer design, ".062thk FR4 Copper Clad" is way too vague. If this design is impedance controlled, it will need to spec the impedance along w/ a layer stackup. You need to get with EE and contract mfr and get requirements spec'd on the fabrication drawing. Just some thoughts I had time for this morning.. Hope this helps. -- Kelly Kelly Dack PCB Dsnr Reno, NV -----Original Message----- From: DesignerCouncil [mailto:[log in to unmask]] On Behalf Of Gary Bremer Sent: Wednesday, January 12, 2005 7:18 AM To: [log in to unmask] Subject: [DC] Hello Designer Council members At the company I am working for is calling out matterial .062 thick FR4 green copperclad laminate for their bare board. My question for the form: When this design was done in the Northeast by the electrical engineer and outsourced to a board assembly house as a turnkey component. What type of quality problems can I expect to deal with durning final assembly and final test? What long term (customer returns) problems may result from this? Do the board fabracation houses on the east coast march to a different drummer than the rest of the country? The electrical engineer does not want to change the drawing to specify what laminate matterial he truly intends to use. The last company I worked for also had this same type of problem. The electrical engineer designs/releases and I have to fix his mistakes. Gary Bremer Senior Manufacturing Engineer Company located in California ---------------------------------------------------------------------------- ----- DesignerCouncil Mail List provided as a free service by IPC using LISTSERV 1.8d To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF DesignerCouncil. To temporarily stop/(restart) delivery of DesignerCouncil send: SET DesignerCouncil NOMAIL/(MAIL) Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail Archives Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 ---------------------------------------------------------------------------- ----- ---------------------------------------------------------------------------- ----- DesignerCouncil Mail List provided as a free service by IPC using LISTSERV 1.8d To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF DesignerCouncil. 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