I agree with Clark's statement. As Mike pointed out, marking may only be
required out in the field or on the test bench, etc. Those individuals
may not make it a habit to carry around a loop so they can read the
markings.
Gary
On 6/17/2010 9:17 PM, Clark Webster wrote:
>
>
> ________________________________
>
> From: IPC-600-6012 on behalf of Nick Koop
> Sent: Thu 6/17/2010 1:47 AM
> To: [log in to unmask]
> Subject: Re: [IPC-600-6012] Legibility of Marking
>
>
>
> John,
>
> I agree 2X seems more appropriate. Higher magnifications are unlikely
> to improve legibility, and the whole point of legend marking is to be
> legible to the unaided eye anyway.
>
> Nick
>
> Nick Koop
> Minco Products, Inc
> Flex Circuits Product Marketing Manager
> Ph 763 586-2846
> Mobile 763 245-4825
>
>
>
>>>> Thomas<[log in to unmask]> 6/16/2010 10:48 PM>>>
>>>>
> We indeed have an issue as 3.1.4 allows up to 3X! This needs to be
> addressed quickly. My position is 2X should be max. Tom
>
> Sent from my iPhone
>
> On Jun 16, 2010, at 12:59 PM, "Dupriest, Don"<[log in to unmask]>
>
> wrote:
>
>
>> Yea, looked at the 4781 some and it does good job of covering
>> "qualification testing" but I think I saw it points back to 6012 for
>>
>
>> production lot testing. So I think our job will be to add to table
>>
>
>> 4-3 lot conformance AQL as required. The table of qualification
>> test is too much so we just need to pick what makes good sense for a
>>
>
>> lot to lot check.
>>
>> C. D. (Don) Dupriest
>> Lockheed Martin - MFC
>> Advanced Manufacturing Technology
>> member of:
>> Production Technical Excellence Staff
>> Ph. 972/603-7724 fax: 972/603-9052
>> Email: [log in to unmask]
>>
>>
>>
>>
>> -----Original Message-----
>> From: IPC-600-6012 [mailto:[log in to unmask]] On Behalf Of John
>> Perry
>> Sent: Wednesday, June 16, 2010 2:45 PM
>> To: [log in to unmask]
>> Subject: Re: [IPC-600-6012] Legibility of Marking
>>
>> Hi Wendi and Don,
>>
>> When we revised IPC-A-600 and IPC-6012, we put pointers in both of
>> those documents to the new IPC-4781 qualification and performance
>> specification for legend and marking inks (released in 2008). Prior
>>
>
>> to IPC-4781, there was no industry standard for legend and marking
>> inks aside from an obsolete MIL spec.
>>
>> This document is modeled after IPC-SM-840 for solder mask, and like
>>
>
>> that document, has requirements for adhesion to printed board
>> laminate as well as solder mask.
>>
>> We say in 3.2.10 of IPC-6012C that "Marking inks shall be permanent
>>
>
>> and shall conform to IPC-4781 or be as specified in the procurement
>>
>
>> documentation.
>>
>> I agree with Don though, that we should examine this further within
>>
>
>> our two task groups. IPC-A-600H says the boards shall be inspected
>>
>
>> at no greater magnification than 2X for marking legibility.
>> IPC-4781 says the following:
>>
>> 3.1.4 Legibility After marking is tested in accordance with the
>> methods outlined in this document, excluding flammability, markings
>>
>
>> which are missing in whole or in part, faded, smeared, or shifted
>> (dislodged) to the extent that they cannot be readily identified at
>>
>
>> not more than 3X
>> magnification, shall constitute failure.
>>
>> Opps...
>>
>> Best Regards,
>>
>> John Perry
>> Technical Project Manager
>> IPC - Association Connecting Electronics Industries®
>> 3000 Lakeside Drive # 309S
>> Bannockburn, IL 60015-1249 USA
>> +1 847-597-2818 (tel)
>> +1 847-615-7105 (fax)
>> +1 847-615-7100 (Main)
>> [log in to unmask]
>> www.ipc.org
>>
>>
>>
>> -----Original Message-----
>> From: IPC-600-6012 [mailto:[log in to unmask]] On Behalf Of
>> Dupriest, Don
>> Sent: Wednesday, June 16, 2010 1:55 PM
>> To: Listserv IPC-600-6012
>> Subject: Re: [IPC-600-6012] Legibility of Marking
>>
>> Hi Wendi, I would say yes it applies to component marking (reference
>>
>
>> designators). Examples in 600 mostly reflect numbering (like
>> traceability) but one example photo shows a component symbol. As to
>>
>
>> legibility; I would prescribe to if you can interpret the letters or
>>
>
>> symbol with 2X it is fine. However, this section probably could
>> stand some more work. One thing we have noticed is 6012 does not
>> specifically address adhesion for marking like solder mask is
>> covered in 600 and 6012. It references a permanency requirement so
>>
>
>> one would assume tape test and/or solvent resistance would be
>> applicable. But a tape test may be too difficult to pass for some
>> really small feature sizes/designator letters.
>>
>> Guess just another thing to add to the committee to do list.
>>
>> C. D. (Don) Dupriest
>> Lockheed Martin - MFC
>> Advanced Manufacturing Technology
>> member of:
>> Production Technical Excellence Staff
>> Ph. 972/603-7724 fax: 972/603-9052
>> Email: [log in to unmask]
>>
>>
>>
>> -----Original Message-----
>> From: IPC-600-6012 [mailto:[log in to unmask]] On Behalf Of Wendi
>>
>
>> Boger
>> Sent: Wednesday, June 16, 2010 1:05 PM
>> To: [log in to unmask]
>> Subject: [IPC-600-6012] Legibility of Marking
>>
>> Everyone,
>>
>>
>>
>> Does section 2.8 Marking in IPC-A-600 apply to Legend (component
>> mark)? We are increasingly seeing designs with very small legend
>> features causing discussions at final inspection as to whether they
>>
>
>> meet
>> the requirement for legibility. From what I understand legible
>> means at
>> no more than 2x you can understand what the symbols are. Fussiness
>>
>
>> and
>> filled in holes in letters are allowed if you can tell what the
>>
> letter
>
>> is.
>>
>>
>>
>> Would appreciate some guidance on this.
>>
>>
>>
>> Thanks,
>>
>> Wendi
>>
>>
>>
>>
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