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Polarity of parts in packages

JC Leigh


Polarity of parts in packages | 28 October, 1999

Hi all,

Been thinking about this problem because it's costed us some errors before. For the same type of parts from different vendors, the polarity of parts in the taping may differ from vendor to vendor. (Actually, we find that parts from most vendors are in the same orientation, but about 10% is in the opposite polarity.) It's easy for the OP's to forget to check the polarity everytime we switch to another vendor's parts on the same production run. Furthermore, our programmers would need to know the orientation of each part in order to program correctly the first time around. Has anyone thought of a solution for this issue? Or has anyone tried to request vendors to package their parts in a certain orientation?

Thanks, JC

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Dave G


Re: Polarity of parts in packages | 28 October, 1999


Seen this before, many times. We fixed our problems at the co I work for by giving a packaging specification to our purchasing dept. Took some work but the payoff was pretty big.

This document includes such things as orientation,pitch,tape type,Esd Req,Moisture specs,elect specs,etc. We use multiple vendors for several of our soic's,Bga's & qfp's. Until we started doing this we probably had 1-2 wrong orientations in a 3-4 month span. Most get caught fairly quickly but it still adds up to a lot of rework. The # of incidents has gone down quite a bit since implementing the packaging spec. I think it's probably been 6 months or more since our last incident.

I've even seen problems within the same vendor. Same part #, same vendor different location. If a vendor is putting parts in tape by hand you can get various rotations in the same reel. We usually reject lot #'s of parts if this occurs. We return them for inspection & re-taping if necessary.


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Re: Polarity of parts in packages | 29 October, 1999


We 'had' this problem previously, but eliminated it for good by using the following:

(1) Create a procedure for part orientation that follows IPC standards. Give a copy of this procedure to your receiving department, your buyers, as well as all your suppliers. (2) Maintain a orientation book that lists the orientation of every package type used in your process. Believe it or not, some suppliers may have a difficult time achieving the orientation you need, so if your standard is going to support non-IPC standards, this book will maintain such orientations.

We've implemented both, and the problems are now gone.

You must remain dedicated to maintaining your orientation book. We do, and our programmers do not experience any issues that affect the floor directly (since they are caught in the earlier phases.)

Good luck!

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JC Leigh


Re: Polarity of parts in packages | 31 October, 1999

Can you please give me a pointer on where to find the component package orientation standard in the IPC? I think we'll work up a spec sheet for the folks in purchasing and let them handle the vendor side of this problem.

Thanks for your help!


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