Re: [PEDA] WANTED: PCB Expert (Off Topic)
Jason, You indicate the Profile is Optimum according to Fab. Which I conclude to be, that the layer stack up order is balanced around the center line of the board stack up.. As well , you indicated or implied the copper is equally distributed on each signal pair and internal plane pairs on either side of the center line of the layer stack up. Which means No odd numbered plane layers or signal layers..in the stack up.. etc.. No predominate copper pour areas in one section of the board vs. another.No split plane areas that are not balanced by a corresponding split plane area.. on the other side of the centerline of the layer stack up...etc. I have discovered that a balanced copper distribution is the number one requirement to control and or minimize warpage. If there is substantial difference in the percentage or density of copper on the signal layers, you will see differential expansions during reflow. That differential force will warp and twist the board and as it has been said in the past post a quick cool down will set the twist or warp. You indicated the component layout and thermal profile are probably not to blame. The question I ask, Is there a higher concentration of direct connection to the plane in one area vs.another?This will have a tremendous heat sinking differential and could cause a warpage as well. If all is well in the areas mention above.. Then that leaves Fab. shop with the lions share of the responsibility for warped boards if in fact the above conditions are met. Generally plating differentials are not enough to warp a board beyond 10% out of plane.. Fab. will need to review their process controls. Speed (time in the flow) and temperature here are the main parameters. I would look at the speed or the amount of time the board in the jig is sent through the Flow. If you can prove and or get fabrication to admit it is not in the design or layer stack up then it becomes their full responsibility and you should not have to pay for warped boards. Here, I assume you have in your fabrication drawings a specification that defines the acceptable percentage of warpage. That is my two cents.. Sam Cox. At 04:40 PM 4/4/2002 +0100, you wrote: Thanks for all the advice and suggestions. Some more info that I missed from the first post: We've been trying to solve this for some time. We've tried boards supplied from more than one house and populated at more than one house, all with the same sorts of results. We're not the fab, so we have no control on the process, its up to their QA. The profile is optimum (according to fab) and any change would result in bad joints. We've tried reflow and wave with the same or similar results. We've tried with and without components with the same or similar results. So the component layout and thermal profile probably are not to blame. It must be the board design or the results of that combined with the conventional layup for such a design. I can't say who designed the rack, but to our knowlege their own cards fit into the rack OK - even though our samples are twisted to a small degree. We're prepared to try adding hashing to the inner layers - it seems logical, but as the PCB house seem not to be sure we don't want to spend the money on a run without all the available information (it costs 2k for each run). I'll keep you all informed of the solution and the outcome, thanks once again for all the help. Jason -Original Message- From: Jon Elson [mailto:[EMAIL PROTECTED]] Sent: 03 April 2002 21:53 To: Protel EDA Forum Subject: Re: [PEDA] WANTED: PCB Expert (Off Topic) Jason Morgan wrote: Many thanks, Details are as follows: 6 Layer 1.6 FR4 8 x 10 Board PCB support is a wasted rectangle 10mm wide along all edges, supporting PCB at 2 or 3 points along each edge. (First observation is that this should have copper layers) A number of different ways to even out copper coverage on layers on opposing sides of board were mentioned, and these are probably aimed at solving residual stresses left in the board. That sounds good, but may be difficult to accomplish, dpending on board density, etc. One thing that comes to mind is that the boards come out of the laminating press flat, go through all the additional steps in PCB fabrication OK, but then warp when YOU process them to attach components. Are you sure you have to heat the boards as hot, for as long as you are doing, to get good soldering? That may have something to do with it. Finally, could you give the boards some mechanical support during the reflow soldering? Making some simple metal frames that hold the board edges during the entire time it is heated might keep them flat as they cool. Jon * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * To post a message: mailto:[EMAIL PROTECTED] * * To leave this list visit: * http://www.techservinc.com/protelusers/leave.html * * Contact the list manager: *
Re: [PEDA] New Question.. Best Practices...
Hello everyone.. We have pretty much beaten to death the definition of PWA, PWB, PCA, PCB. Now that we know what we are talking or not talking about.. The question I have is What are the top Ten or twenty(now a days) DFM Best Practices process steps, or checks or suggestions you might look for to ensure a design is right the first time you send it to manufacturing.. When I say manufacturing I mean fabrication, assembly and test. I am trying to put together a checklist that will address 80-95% of the problems that seem to come back from manufacturing causing delay or a respin.. increased cost etc... Thank you in advance. Sam Cox... * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * To post a message: mailto:[EMAIL PROTECTED] * * To leave this list visit: * http://www.techservinc.com/protelusers/leave.html * * Contact the list manager: * mailto:[EMAIL PROTECTED] * * Forum Guidelines Rules: * http://www.techservinc.com/protelusers/forumrules.html * * Browse or Search previous postings: * http://www.mail-archive.com/proteledaforum@techservinc.com * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
Re: [PEDA] Hanging Track
I believe it is more like hanging Chads... That brings back bad memories.. too.. At 11:35 AM 2/1/2002 -0500, you wrote: Is that like a dangling participle? Sean James PCB Designer Telecast Fiber Systems, Inc. 102 Grove Street Worcester, MA 01605 (TEL) 508.754.4858 x33 (FAX) 413.541.6170 - Original Message - From: Dave Babcock [EMAIL PROTECTED] To: Protel EDA Forum [EMAIL PROTECTED] Sent: Friday, February 01, 2002 11:02 AM Subject: [PEDA] Hanging Track Hi All, Does anyone know how to detect a hanging track in PCB? I. E. a track from a via or pad that goes nowhere. Thanks again, Dave Babcock Chief Engineer Cardinal Components, Inc. email : [EMAIL PROTECTED] Phone: 973-785-1333x565 Fax: 973-785-0053 * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * To post a message: mailto:[EMAIL PROTECTED] * * To leave this list visit: * http://www.techservinc.com/protelusers/leave.html * * Contact the list manager: * mailto:[EMAIL PROTECTED] * * Forum Guidelines Rules: * http://www.techservinc.com/protelusers/forumrules.html * * Browse or Search previous postings: * http://www.mail-archive.com/proteledaforum@techservinc.com * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
Re: [PEDA] .TXT File generation
Hello,,, Mid is the geometric center of the spans of all of the pins in a component.. (not the body outline.) Ref is the origin of the component when the component was created in the library.. Pad is Pad1 of the component... Most of the time the component is and I believe should be built with the origin (Ref) at the center of PIN 1 so that when placement is performed you have the best chance to align all or the most number of pins to a testable /routing grid.. Since Protel does such a great job of calculating the centroid for the mid of the component anyway. Secretly the object of the game is to get as many pins as possible on an even increment of the routing grid. Which should be an even increment of the placement and tester grid.. Most Assembly houses want the centroid.. which Protel considers to be the Mid.. for surfacemount components... However they want pin1 for axials etc. You can easily provide that by providing the PIK file.. The X,Y coordinates are based from where the origin of the workspace is defined at the time in which you generate the PIK file.. so if you move the origin (set) it to a fiducial or tooling hole prior to generating the PIK file then all coordinates (X,Y) will emanate from that point.. Also doubly cool from a manufacturing perspective... Rotation is based upon the orientation of the component outline at the time it was originally created in the library.. meaning.. if one DIP16 was created in the vertical that would be considered 0 rotation.. if another DIP20 was created in the horizontal in the library it too would be considered 0 also , so when both are place in a workspace or database.. so that they looked vertical .. one would have an rotation of 0 and the other 90.. due to their different orientation at the time of their respective creations. Hope this helps... Sam * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * To post a message: mailto:[EMAIL PROTECTED] * * To leave this list visit: * http://www.techservinc.com/protelusers/leave.html * * Contact the list manager: * mailto:[EMAIL PROTECTED] * * Forum Guidelines Rules: * http://www.techservinc.com/protelusers/forumrules.html * * Browse or Search previous postings: * http://www.mail-archive.com/proteledaforum@techservinc.com * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
Re: [PEDA] Component Rotation
Steve... 1.) the question should be rephrased to Symbol Rotation.. not Component Rotation.. 2.) Why would you want to rotate a symbol in Schematic capture to something other than 90 degrees.? This not standard practice. Also, keep in mind that your pins of the symbol need to end up on a schematic grid point for wire connection to be completed.. Answer: I do not even believe you can adjust the rotation of a symbol in schematic to some angle other than 90 degrees.. Workaround: If you are all fired up to still do it.. you will need to create the symbol at 45 degrees in the library to start with.. just make sure the pins are on an even 100mil grid.. Best wishes.. At 05:02 PM 10/24/01 +0200, you wrote: Steve wrote: Can anybody answer this quicker than me attempting to find it in help files. I know how to adjust the rotation steps in PCB editor, but how do you adjust in in schematics from 90 degrees to 45 degrees. Steve Steve, As far as I can see, you can only rotate in steps of 90 degrees in schematics. Have a nice day! Joop Reekers Semecs bv, Almelo NL * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * To post a message: mailto:[EMAIL PROTECTED] * * To leave this list visit: * http://www.techservinc.com/protelusers/leave.html * * Contact the list manager: * mailto:[EMAIL PROTECTED] * * Forum Guidelines Rules: * http://www.techservinc.com/protelusers/forumrules.html * * Browse or Search previous postings: * http://www.mail-archive.com/proteledaforum@techservinc.com * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
Re: [PEDA] Fw: Fw: THIS SAYS IT ALL!!!!!
Right On Well put At 12:21 PM 10/23/01 -0700, you wrote: - Original Message - From: mailto:[EMAIL PROTECTED]>[EMAIL PROTECTED] To: mailto:[EMAIL PROTECTED]>[EMAIL PROTECTED] Cc: mailto:[EMAIL PROTECTED]>[EMAIL PROTECTED] ; mailto:[EMAIL PROTECTED]>[EMAIL PROTECTED] ; mailto:[EMAIL PROTECTED]>[EMAIL PROTECTED] ; mailto:[EMAIL PROTECTED]>[EMAIL PROTECTED] ; mailto:[EMAIL PROTECTED]>[EMAIL PROTECTED] ; mailto:[EMAIL PROTECTED]>[EMAIL PROTECTED] ; mailto:[EMAIL PROTECTED]>[EMAIL PROTECTED] ; mailto:[EMAIL PROTECTED]>[EMAIL PROTECTED] ; mailto:[EMAIL PROTECTED]>[EMAIL PROTECTED] ; mailto:[EMAIL PROTECTED]>[EMAIL PROTECTED] Sent: Friday, October 19, 2001 1:15 PM Subject: Fwd: Fw: THIS SAYS IT ALL! In a message dated 10/18/2001 2:13:31 PM Eastern Daylight Time, mailto:[EMAIL PROTECTED]>[EMAIL PROTECTED] writes: Broken Arrow, Oklahoma School officials remove "God Bless America" signs from schools in fear that someone might be offended. Channel 12 News in Long Island, New York, orders flags removed from the newsroom and red, white, and blue ribbons removed from the lapels of reporters. Why? Management did not want to appear biased and felt that our nations flag might give the appearance that "they lean one way or another". Berkeley, California bans U.S. Flags from being displayed on city fire trucks because they didn't want to offend anyone in the community. In an "act of tolerance" the head of the public library at Florida Gulf Coast University ordered all "Proud to be an American" signs removed so as to not offend international students. I, for one, am quite disturbed by these actions of so-called American citizens; and I am tired of this nation worrying about whether or not we are offending some individual or their culture. Since the terrorist attacks on September 11, we have experienced a surge in patriotism by the majority of Americans. However, the dust from the attacks had barely settled in New York and Washington D.C. when the "politically correct" crowd began complaining about the possibility that our patriotism was offending others. I am not against immigration, nor do I hold a grudge against anyone who is seeking a better life by coming to America. In fact, our country's population is almost entirely comprised of descendants of immigrants; however, there are a few things that those who have recently come to our country, and apparently some native Americans, need to understand. First of all, it is not our responsibility to continually try not to offend you in any way. This idea of America being a multi-cultural community has served only to dilute our sovereignty and our national identity. As Americans, we have our own culture, our own society, our own language, and our own lifestyle. This culture, called the "American Way" has been developed over centuries of struggles, trials, and victories by millions of men and women who have sought freedom. Our forefathers fought, bled, and died at places such as Bunker Hill, Antietam, San Juan, Iwo Jima, Normandy, Korea, Vietnam, We speak English, not Spanish, Arabic, Chinese, Japanese, Russian, or any other language. Therefore, if you wish to become part of our society - learn our language! "In God We Trust" is our national motto. This is not some off-the-wall, Christian, Right Wing, political slogan - it is our national motto. It is engraved in stone in the House of Representatives in our Capitol and it is printed on our currency. We adopted this motto because Christian men and women, on Christian principles, founded this nation; and this is clearly documented throughout our history. If it is appropriate for our motto to be inscribed in the halls of our highest level of Government, then it is certainly appropriate to display it on the walls of our schools. God is in our pledge, our National Anthem, nearly every patriotic song, and in our founding documents. We honor Christ's birth, death, and resurrection as holidays, and we turn to Him in prayer in times of crisis. If God offends you, then I suggest you consider another part of the world as your new home, because God is part of our culture and we are proud to have Him. We are proud of our heritage and those who have so honorably defended our freedoms. We celebrate Independence Day, Memorial Day, Veterans Day, and Flag Day. We have parades, picnics, and barbecues where we proudly wave our flag. As an American, I have the right to wave my flag, sing my national anthem, quote my national motto, and cite my pledge whenever and wherever I choose. If the Stars and Stripes offend you, or you don't like Uncle Sam, then you should seriously consider a move to another part of this planet. The American culture is our way of life, our heritage, and we are proud of it. We are happy with our culture and have no desire to change, and we really don't care how you did things where you came from. We are
[PEDA] Hello! It is Mechanical NOT Mechanikal OK!!
Maybe you can not get it to work right because you can not spell it right. * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * To post a message: mailto:[EMAIL PROTECTED] * * To leave this list visit: * http://www.techservinc.com/protelusers/leave.html * * Contact the list manager: * mailto:[EMAIL PROTECTED] * * Forum Guidelines Rules: * http://www.techservinc.com/protelusers/forumrules.html * * Browse or Search previous postings: * http://www.mail-archive.com/proteledaforum@techservinc.com * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
[PEDA] Resource for design (inpedance calculator etc.)
Tim, below are some very valuable resouces, http://www.robertsondne.com/ http://www.ultracad.com/articles.htm http://www.merix.com/resourcecntr/res_intro.html UltraCad as well as Chris Robertson's site have impedance Calculators. Merix has a great DFM manual.. Enjoy Sam Cox * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * To post a message: mailto:[EMAIL PROTECTED] * * To leave this list visit: * http://www.techservinc.com/protelusers/leave.html * - or email - * mailto:[EMAIL PROTECTED]?body=leave%20proteledaforum * * Contact the list manager: * mailto:[EMAIL PROTECTED] * * Browse or Search previous postings: * http://www.mail-archive.com/proteledaforum@techservinc.com * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
Re: [PEDA] Warping on small odd layer boards.
Tim, Take a look athttp://www.merix.com/resourcecntr/apps/balanced_pcbs.htmlit is an article on Balanced board stackup... it will explain it best... Sam Cox... > >> -Original Message- >> From: Tim Hutcheson [mailto:[EMAIL PROTECTED]] >> Sent: Wednesday, August 22, 2001 10:53 AM >> To: Protel EDA Forum >> Subject: [PEDA] Warping on small odd layer boards. >> >> >> >> Has anyone any experience building small (4x7 inch) 7-layer >> .063" boards? I would like to have a certain stack up impedance that is best met with >> 4,9,9,9,9,4 for the 5-mil trace widths I am using but I know >> from what I have read that warping can be a problem. On the other hand, >> a conventional 8-layer board would thin the layers and upset the >> impedance and a 6-layer board adds impedance calculation problems and more layout issues. >> >> Do vendors even build odd layer boards? ANSWER: YES, not suggested however...see article... >> >> regards, >> >> Tim Hutcheson > > * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * To post a message: mailto:[EMAIL PROTECTED] * * To leave this list visit: * http://www.techservinc.com/protelusers/leave.html * - or email - * mailto:[EMAIL PROTECTED]?body=leave%20proteledaforum * * Contact the list manager: * mailto:[EMAIL PROTECTED] * * Browse or Search previous postings: * http://www.mail-archive.com/proteledaforum@techservinc.com * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
