4 Replies Latest reply on Sep 11, 2009 6:02 AM by strangd

    Angle Plowing problem in Expeditionpcb

    yu.yanfeng

      To avoid FR4's Fibre-Expoxy skew, Intel recommand that all PCIe-2/3 differantial paires should be routed in an 10 angle. It's difficult to effectively plow pairs in this angle. We try to use the alternative, routing in normal mode, but rotate whole design before generated out fab data(gerber and drill) using keyin "ra 10".  It sounds a good mathod. However, much of opens will occure after the rotation. I have logged this bug in the supportnet. You may try this, and I garantee you should see same symptom in your side.

       

      Yanfeng

        • 1. Re: Angle Plowing problem in Expeditionpcb
          strangd

          Had the problem years ago when and we tried a 45° angle of trace to warp and weft of glass re-enforcement.  We reduced the final size of the panel and lived with the wasted FR-4 since we rotated the panel layout to get the angle.

           

          I had heard that 11° was the preferred angle over standard FR-4 glass.  Would you take a big price increase by going to a flat weave of the glass instead of the bundles?  That should allow you to route normally and have no rotation of the panel up to 10GHz.  Other than a handful of SAS hard drive controller boards, most of my stuff is low volume aerospace designs, RF and high speed data acquisition.  So I just move up to a more expensive laminate material.

           

          Good luck

          Dwain

           

           

           

          • 2. Re: Angle Plowing problem in Expeditionpcb
            yu.yanfeng

            Hi Dawin,

            Thank you very much.

            If the rotated design be saved and re-open it, most of opens will disappear but there are some opens still exist. It's very annoyed. I hava touched our fab partners, they said th prices will increase some if rorated because they have issues with the panel usage(of course it's not aways true).  The best method is

            route those traces in the angle.

            Yanfeng

            • 3. Re: Angle Plowing problem in Expeditionpcb
              strangd

              Since there are going to be other people reading these postings, I guess that there should be some explanation of how to design these odd angle routing boards as rotating the entire design at the time of panelization is not the best answer.  If you are locked into using standard FR4 type laminates and can not buy the high speed or RF board material, you can route the 6GHz and higher traces at 10º or 11º to the layout of the warp and weft.

               

              When you get to the point where you are routing the 6GHz traces you can rotate the board in the design database by keying in “ra 11” (rotate all 11º.) Make the trace routes as far as possible and then key in the board rotation needed for the next section of the routed traces.  It the end, rotate the board back to an orthogonal relative to the board’s original layout; like the direction that you started with.  You still should be able to slide your angled traces back and forth in Route Mode.  You could turn on odd angle pad entry but it may not be necessary.

               

              I have been known to get into Draw Mode and place lines into the database.  Select the line, open Properties and then type in an angle of 11º.  This places the line at the angle that I want.  In Properties I can change the line to a trace, give it a width and then tag a net to it.  Back in Route Mode, I can route a trace to either end.

               

              If you have routed a trace in the 0º-45º-90º mode, you can get into Draw Mode, select a vertex and drag it so that a trace section is 11º.  (Hit the Save button often.) Hitting the Alt Key as the selected corner is dragged is not for the faint of heart.

               

              When in Route Mode, if you like to select a trace vertex, hold down the Ctrl key and drag in order to form a curve, this may not work after one of the segments is at a non-0º-45º-90º angle.

               

              Good luck

              Dwain

              • 4. Re: Angle Plowing problem in Expeditionpcb
                strangd

                I have just loaded EE2007.6 and the third up-date.  This version of Expedition has a lock feature to Angle Route.  Which means that you can continue routing a trace at the same angle as the previous segment.  Unless I have missed something you can not dial in an active angle and then have the software route to it.  (Actually, a set of angles would be better.)  But while in Angle Route mode you do get a readout of the route angle that you can use.  This may be a few minutes off of the preferred routing angle.  In the earlier posting I gave the method that I use to get THE angle that I wanted; still true.  But I should not let anyone think that being off by a minute or two or three is not acceptable.  Use the Angle Route feature available in the recent releases.

                 

                Using Ctrl-drag to place a curve at the intersection of two trace segments may work if one of the segments is 0º-45º-90º but still does not work if both segments are at odd angles.

                 

                Dwain