2 Replies Latest reply on Dec 1, 2011 10:30 AM by wes_clow

    MODIFY ORIENTATION AND ORIGIN OF FOOTPRINT IN LIBRARY AND UPDATE LAYOUT FROM LIBRARY WITH NO CHANGES TO PCB ARTWORK

    wes_clow

      We have two PADS Layout v9.1 issues.

       

      One, some of our library footprints do not match the reel orientation causing rotation errors in the placement file. So, we need to spin the footprints in the library and then update the board with the new footprint to correct the rotation information in the placement file.

       

      Two, some of our library footprints have the origin in the wrong location, instead of being at the point where it should be picked up by our placement machine the origin is centered on a pin. So, we need to move the origin of the footprints in the library and then update the board with the new footprints to correct x,y data information in the placement file.

       

      Ideally, we would prefer to make no manual changes to the layout after updating from the footprint library.

        • 1. Re: MODIFY ORIENTATION AND ORIGIN OF FOOTPRINT IN LIBRARY AND UPDATE LAYOUT FROM LIBRARY WITH NO CHANGES TO PCB ARTWORK
          yan_killy

          Hello Wes,

           

          If that is the only way you can solve your problem, than you will have to do some manual clean up of the design after you have replaced the part with modified definition from the library.

           

          I do not know what pick and place assembly equipment you are using; however there are many manufacturing software packages that will take CAD data and modify orientation of component based on how they are delivered to assembly machine. Also same software can change or derive its own centroidal data for each component no matter how is the origin was defined in CAD library.

           

          What I am trying to say is that is not the approach I would take. For example you will change the library for the part in question. Your purchasing is buying this part on Real/Tape. Then next time they will buy it from a different vendor and it will cope in a cassette and orientation may change. Consider another situation. Your Cad Library part is correct to respect tt Real/Tape, nevertheless your assembly machine have multiple feeders from different quadrants and that in itself changes the orientation and your CAD library part want work again.

           

          By no means am I an expert in assembly techniques, but I will not want to manage with CAD Library Assembly Machines.

          Regards, Yan

          • 2. Re: MODIFY ORIENTATION AND ORIGIN OF FOOTPRINT IN LIBRARY AND UPDATE LAYOUT FROM LIBRARY WITH NO CHANGES TO PCB ARTWORK
            wes_clow

            Hey Yan,

            we have a little more control over purchasing (we specifically use part numbers that are tape and reel), so the vast majority of our problems exist on parts that always come in reels (ie. 0805 resistor, 0402 caps, etc...). I found a quick fix that just rotates and applies an offset in a placement file extraction .bas script. This works well, but management wants to fix the library and update actual PADS layouts, so that the library and board are correct. I found a way to do this by exporting the .asc file, modifying the orientation and x,y data manually and then importing it into a new .pcb file. This works pretty well and takes a little less time than manually changing the layout itself. I think we are planning to write a VB or VC++ program to modify the ascii file for us using a look up table. I am also checking to see if I can use .bas scripts to change the ascii data as I export it.

             

            Thank you very much for the quick reply!

             

            I have a ticket in with PADS service and we will see if they have a better way of doing it. We have not found any other way to minimize or megate manual changes or automate this pocess beyond what is described above.

             

            Sincerely,

            Wes