FYI
        We count defects very similar to the way Rick has mentioned with the
exception that if a solder short has affected more than 2 leads the no. of
shorts is Leads affected minus 1 with in a grouping.  I think this scenrio
more closely corelates to the way the opportunities were determined (i.e. no
of lead that are potential for a short).

P.S.  The assembly oportunities should also include 1 for the board and 1
for each stamp, label but these are insignificant numbers compared to often
2000 - 3000 solder and placement oppertunities per board.  We also track our
solder defects against just the solder opportunities and the
placement/assembly defects against those opportunities to see how different
products compare.  As can be imagined solder DPM is very consistant amoungst
most products.  Placememnt defects however very, based off the density,
package lead counts and # of oddball components.

        
                                        Mark Spitnale,
                                        Hughes Defense 
                                        [log in to unmask]

Resent-Sender: [log in to unmask]
>>
>>We count our defect opportunities as follows: one per component plus
>>one per solder joint. A resistor would be three defect opportunities, a 144
>>pin QFP would be 145 defect opportunities.
>>
>>We count actual defects as follows: Tombstone part is one defect.
>>Insufficient solder on one pad is one defect. Solder short between three
>>legs of an SOIC is one defect. Skewed SOIC is one defect.
>>
>>I have concerns that we are presenting an artificially low PPM rate by
>>counting defects this way. Others have concern that if we count defects
>>the same way we create opportunities, the PPM numbers will be inflated.
>>
>>I'm looking for info on how others in the industry count actual defects that
>>affect more than one opportunity.
>>
>>Thanks.  Rick Vernon, QA Manager   [log in to unmask]
>>
>>***************************************************************************
>>*
>>
>>
>-
>
>
----------------------------------
Mark W. Spitnale                Phone: (219) 429-5992   Fax: (219) 429-
Hughes Defense Communications                           Mail Stop: 25-31
1010 Production Road, Fort Wayne, IN 46808-4106
Email: [log in to unmask]

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