Sorry, Let me try again. (I don't know what happened the last time.) Being a slave to "Standards" is not where we should be as an industry. The "standards" are, in reality, minimum acceptable criteria. I often hear manufacturers state that they build to a standard or their product meets the "standards." However, as I inspect these products per the same standards (mostly IPC-A-600 and IPC-A-610), I see that while the product might meet the “Standards” it was manufactured along the minimum edge of acceptability per the standard. An example: Visible, opaque particulates embedded in the solder mask might meet the IPC-A-610 standard if they do not encroach on certain areas of the PWB. But what does finding multiple occurrences of particulates in the solder mask mean in terms of the PWB manufacturing quality? Unless you are dealing with military classes, in mass production a close visual inspection can only be performed on a limited number of units. If those units barely meet the standard what does that indicate about the remainder? (How many particulates might be embedded within the PWB layers where they are not readily visible? And of these how many could eventually cause a short?) Meeting the Standards is not sufficient to build a reliable product. The standards must always remain as the minimum acceptable criteria not as the expected mean or median product. The IPC committees put long hours into each specification to clarify points and make the items as understandable as possible. IPC-A-610E (and later revisions) is a great asset. Pictures showing both the good and the bad are presented. But never is it stated in the specification (that I have read) that a process that consistently produces products at the edge of acceptability (per the standard) is acceptable to industry. Having said that I must agree with Brian’s statement: “In short, Standards, used appropriately, can help, as far as possible, to perfect reliability for a given application. Used inappropriately, they can drive up costs dramatically …” There needs to be common sense in the application of the standards, both from a user and a manufacturer point of view. Customers’ don’t want manufacturers to hide behind the “Standards’ Wall” when confronted with issues with their products. And the products should be manufactured in a manner that places only the smallest percentage, (ideally none) of products below these limits. mark Mark Woolley |PTRL Laboratory | Avaya | 1300 West 120th Ave | Westminster, CO 80234 USA | Voice (Lab): (303) 538-2166 | email: [log in to unmask] | -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Woolley, Mark D. (Mark) Sent: Monday, May 02, 2011 8:13 AM To: [log in to unmask] Subject: Re: [TN] "The Curse of IPC-A-610 and IPC-J-STD-001" - opinion piece by James Smith z{S}ĝxjǺ*'O*^mZw!j Vr 6f F%FFG2B WR R B&R2W7'R'7&2"& VGV6WFR7&FWFV"Vf7G&W2 FR FW'VBF FFB" V" &V7WG FR7FF&G"Wf"27V7 FW6 G7G " R6R FFG27F22c6V FBvRF G7B֖BVB R( 7FF&G( v2fGWVBrFVVFRb66 F&G " R7FF&BWSf6RR '7W2VVFVBF 6F"6vWBF2c FFBb WFB7W'V FRt"WBvBWfFrVFR6W'VW2bFVFW FR W"V F& FRt"Vf7G&r VGVW7 R&RFVƖr FƗ'67W272 &GVF66 f7V7V76& &f&B֗VBV&W VGb R 2&ǒVB R7FF&BvBW FB6FR&WBF &F#r '7W2֖B&RVVFVBv FRt"W' vW& FW&B V f6SBbF6R6BWfGƒWR 6'VFr R7FF&GB Vf6V F'&VR &GVBFR FFG2WBv2&V FRV6WFR7&FW FR7FBVF &V7F2֗GVW BW'FV Vf6 F6&gGB FRFV22 F'7&R2 7&R2cRBF" Wf62w&B7WB7W&2 &FFvB FRB& W6FB'BWf"2B FVBF 7V6fFFBf &B FB &W7 FB66FVF G6W G7G FRFv6WFG" R7FF&B6WFRFW7'fr6B WBw&R F'( 2 FVC B7FF&G 6V & &Fǒ6V2"26RFWfVB V&Ɨ"f 6FW6B & &FǒFG&fRW6G2G&6 (n(FW&VG F&6 VR R ƖFbF 7&2&&W6"BfGWW"Bbfr77FW>( vBVf7G&W2 F&B R( 7FF&G( v v&FV vF7VW vFF" &GVG2BF G7G 6VBRfGWVBW"FB W2 R67BW6VFRVǒRb &GVG2&VrF6RƖGW E$&F'f vWB# fRW7֖7F"43BU R32S3#cbâvƖf6 &vW6RҤgF6WB֖V6W2&u&bb&0VG&F 3##FF6WDpV&V7SDF7'62cBԢ5D" V6'W6F'F6 6' 7'7B 7V7f"twithstanding, I believe - and I've proposed this idea before - that there is a too slavish adherence to standards rather than to common sense. This is because the standards exist and are used but are not applicable to many applications which do not require top quality reliability. Just the unnecessary inspection is costly, let alone the afterwork. It reminds me of one of my ex-customers making a lab instrument that is used only in comfortable room conditions. He was getting a lot of cratering on his wired through-hole SJs after wave soldering, and he had personnel reworking these joints (which plop-plopped for several seconds of applying the soldering iron). I asked why and he told me that the joints were faulty. I rejoined with something like BS. He gave me a board full of craters but which was otherwise faulty and I did microsections of half-a dozen "faulty" SJs, all of which showed perfect intermetallic formation along both wire and through-hole plating, with the craters and blowholes outside the intermetallics. This persuaded my client that the "fault" was cosmetic and he stopped the retouching except on grossly obvious faults. From that moment, the number of returns was reduced. For pointing out to him that he was wasting money by a too-solicitous inspection and retouching, he presented me with a bottle of Neuchâtel Oeil de Perdrix, which was delicious. Incidentally, it was this case that inspired me to develop what became known as the "Plop-plop Meter" to measure the outgassing of PTHs. This never got beyond prototype stage, but it worked admirably and was able to distinguish between different causes of outgassing. However, I wasn't convinced that the market justified putting it into production; it remained a curiosity. In short, Standards, used appropriately, can help, as far as possible, to perfect reliability for a given application. Used inappropriately, they can drive up costs dramatically and with no justification; this could drive the manufacture to E. Asia, at the cost of jobs. Maybe the author was expressing this sentiment, albeit unscientifically and too clumsily. Let common sense prevail! Brian On 29/04/2011 19:15, Graham Collins wrote: > Anyone else read this? > http://www.assemblymag.com/Articles/Blog/BNP_GUID_9-5-2006_A_10000000000 > 001038283 > > All I can say is "wow". Well, I could go on for hours, but... wow. > Not quite how I see these specs! Working on military stuff I can attest > that changing from MIL-STD-2000 to the IPC specs was a significant > improvement in reality, reliability, and productivity, but that's not > how he sees it. > > regards, > > Graham Collins > Halifax Production Engineering > L-3 communications Electronic Systems > (902) 873-2000 ext. 6215 > > This message and any attachments are solely for the use of the > individual or entity to which it is addressed and may contain > information that is privileged or confidential or controlled technical > data that is subject to the laws of Canada or the United States. 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