Hey Paul, I agree with everything you've said. Also, I'm with an OEM now. If I were the customer in this case and you show me what you have now, I'd tell the supplier to contain the material and work out a solution......quickly. Gerry > Date: Tue, 17 Dec 2013 10:03:25 -0500 > From: [log in to unmask] > Subject: Re: [TN] Crazing > To: [log in to unmask] > > Hi Gerry, > > Based on the responses from "everyone" I am sure that crazing is a > defect that is a concern. It is just that one company is playing > "specmanship" with IPC's rules and I don't like it. > > The rules state that a microsection is not needed to inspect for > crazing. Therefore, according to the fabricator, one cannot inspect for > crazing using a microsection. The specification does not state that a > microsection is prohibited in the inspection for crazing however. IPC A > 600 states that crazing ".. does not require a microsection evaluation". > > Regardless of how I found the defect it is the intent of IPC to reject > this condition if it violates 50% spacing rules. > > I found this condition "along the way" and I raised the flag. That is > all I can do. > > > Sincerely, > > > > Paul Reid > > Program Coordinator > > PWB Interconnect Solutions Inc. > 235 Stafford Rd., West, Unit 103 > Nepean, Ontario Canada, K2H 9C1 > > 613 596 4244 ext. 229 > > Skype paul_reid_pwb > [log in to unmask] > > > > > -----Original Message----- > From: TechNet [mailto:[log in to unmask]] On Behalf Of Gerry Gagnon > Sent: December 13, 2013 8:49 PM > To: [log in to unmask] > Subject: Re: [TN] Crazing > > Hi Richard, > > Have enjoyed your posts over the years and agree with you frequently. > > The answer is that it "depends". > > Yes, the magnifications and switching rules are the "front matter" that > a lot of folks gloss over from time to time. > > I am sure that if you were looking to verify a certan non-conformance > and found something along the way that was lethal for your product or > application, you would have no problem raising that flag. > > By the way "along the way" is just a figure of speach I was using. > Definitely not proper specification language. > > Gerry > > > Date: Mon, 9 Dec 2013 12:52:28 +0000 > > From: [log in to unmask] > > Subject: Re: [TN] Crazing > > To: [log in to unmask] > > > > I am not sure I accept that "along the way" theory completely. > > Prevalent in all of the IPC standards, all defect categories are > provided a magnification level for inspection. For example, if a > non-metallic particle is seen on the PWB while inspecting solder joints > at 20X magnification on a conformal coated CCA, the inspector is > supposed to switch to the required magnification for the particulate > matter (4X-7X). If the particulate matter cannot be seen at that range, > it is not considered to be a defect. > > If you want to entertain your "along the way" theory, then have fun > counting up the rework hours to strip away the coating, remove the > particles, clean, dry, and re-coat. No matter what you do short of > building all product in a Class 10 clean room, this unnecessary rework > will never end. > > > > Of course, one must understand that there are certain exceptions to > this; I am just saying that you cannot allow an "along the way" > philosophy in the factory. It will put you out of business. > > In regards to your example, two questions come to mind: > > > > 1. What is the magnification required when inspecting for particulate > matter between conductors at the PWB level, and what is the minimum > electrical clearance between the two traces you describe? If the > material was visible at the required magnification, it was an escape, > and should have been caught at the higher magnification you describe > anyway, and is a real defect. > > 2. Did you measure the resistance again after the tiny piece of > material was removed, and did it make any difference? > > > > > > -----Original Message----- > > From: TechNet [mailto:[log in to unmask]] On Behalf Of Gerry Gagnon > > Sent: Friday, December 06, 2013 7:21 AM > > To: [log in to unmask] > > Subject: Re: [TN] Crazing > > > > Hi Paul, > > > > Hope you and Bill B. are doing fine. > > > > I am assuming that you you were looking for something else and > detected a "non-conforming" level of crazing. > > > > In my mind, this is an easy one because you found the non-conformance > "along the way" while examining your microsection. > > > > Let me give you an easier analogy. > > > > While examining a region of an IST test coupon in transverse mount, I > find a tiny piece of material bridging two conductors at high mag. > > Clearing away the conductor surfaces enough to measure if there is a > resistance, I get a value in the MegOhm range. > > > > Is it a short? > > > > Unless things gave changed, Bare board continuity thresholds will not > detect this phenomenon. > > Let's also say that innerlayer AOI (if performed) has a very high > escape rate for this type of phenomenon or may not even detect it at > all. > > > > Is the phenomonon a short per IPC A-610? > > My answer is yes, it is an unwanted connection, albeit a high > resistance connection, and is difficult to detect. > > > > Does the fact that I found this short in a cross section under high > magnification, while I was looking for something else, change anything? > > > > I don't think so, and I do not think IPC A-610 allows non-conformances > that are found "along the way". > > > > Have a good one. > > Gerry > > > > > > > > > > > Date: Thu, 5 Dec 2013 16:05:41 -0500 > > > From: [log in to unmask] > > > Subject: [TN] Crazing > > > To: [log in to unmask] > > > > > > I was just on a conference call where we found crazing (a separation > > > > between glass fibers and the epoxy system), in a microsection. The > > > fabricator stated that this had to be evaluated looking at a board > > > macroscopically and could not be evaluated microscopically. > > > > > > > > > > > > Crazing is called out in IPC-A- 600 in section 2, paragraph 2.3.2 > page > > > 18, which is "Externally Observable Characteristics". In A-600 there > > > > is picture of a microsection showing the defect but it states that a > > > > microsection is not required. > > > > > > > > > > > > In IPC 6012-2010 crazing is call out in 3.3.2.2, page 12, which > states > > > (I am paraphrasing), "Crazing shall not violate greater than 50% of > > > the distance between adjacent conductors..." The document then > refers > > > to IPC A 600. > > > > > > > > > > > > What is your take on their argument that crazing should not be > > > evaluated microscopically as per IPC? > > > > > > > > > > > > Sincerely, > > > > > > > > > > > > Paul Reid > > > > > > Program Coordinator > > > > > > PWB Interconnect Solutions Inc. > > > 235 Stafford Rd., West, Unit 103 > > > Nepean, Ontario Canada, K2H 9C1 > > > > > > 613 596 4244 ext. 229 > > > > > > Skype paul_reid_pwb > > > [log in to unmask] > > > > > > > > > > > > > > > > ______________________________________________________________________ > > > This email has been scanned by the Symantec Email Security.cloud > service. > > > For more information please contact helpdesk at x2960 or > > > [log in to unmask] > > > > ______________________________________________________________________ > > > > > > ______________________________________________________________________ > > This email has been scanned by the Symantec Email Security.cloud > service. > > For more information please contact helpdesk at x2960 or > [log in to unmask] > ______________________________________________________________________ > > > > ______________________________________________________________________ > > This email has been scanned by the Symantec Email Security.cloud > service. > > For more information please contact helpdesk at x2960 or > [log in to unmask] > > ______________________________________________________________________ > > > ______________________________________________________________________ > This email has been scanned by the Symantec Email Security.cloud > service. > For more information please contact helpdesk at x2960 or > [log in to unmask] > ______________________________________________________________________ > > ______________________________________________________________________ > This email has been scanned by the Symantec Email Security.cloud service. > For more information please contact helpdesk at x2960 or [log in to unmask] > ______________________________________________________________________ ______________________________________________________________________ This email has been scanned by the Symantec Email Security.cloud service. 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