Brian,
Thanks for confirming our worst suspicions. We were being polite and did
not want to mention it. Don't worry you're still ahead of the rest of
us.
Dewey
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Brian Ellis
Sent: Thursday, January 10, 2008 12:45 AM
To: [log in to unmask]
Subject: Re: [TN] Fwd: Re: [TN] Air bubble in solder resist
I would be quite worried at what I see here. To me, it looks like
vesication. This is caused by the solder mask being placed over a
hygroscopic contaminant. As the mask is semi-porous (as are all
polymers), the contaminant absorbs moisture and forms the bubble where
adhesion is poor. Note that there is a halo round each defect; this
could be because the pressure in the bubble rises and tends to pull the
mask off.
You can confirm this possible diagnosis by autoclaving a board in steam,
using a domestic pressure cooker for 24 h or so (making sure that it
never boils dry). If the problem appears worse, then it is confirmed.
Brian (not brain: I lost that many years ago!)
Luan Nguyen wrote:
> Sorry! I send you file attached but maybe you will not receive it. You
> can see the picture on
> http://picasaweb.google.com/johnynhluan/BubbleDefectOnPCB
>
> Best regards,
>
>
>>>> [log in to unmask] 10-Jan-08 08:32:31 >>>
> Thank you Brain!
> I have some pictures of this defect to refer.
> Please give me a advice for this defect.
>
> Thanks and best regards,
>
>
>>>> [log in to unmask] 09-Jan-08 13:37:58 >>>
> If there is one >0.25 mm, then the board should be rejected.
> If there are 3 or more of <0.25 mm the board should be rejected.
>
> Furthermore, and this is my opinion, if a bubble <0.25 mm is between
> two
> tracks and occupies >50% of the spacing between the tracks, it should
> also be rejected.
>
> Brian
>
> Luan Nguyen wrote:
>> Dear Technet,
>> Our company were been happening a problem on PCB, details:
>> Per IPC-A-600, Revision G
>> 2.9 SOLDER RESIST (Solder Mask)
>> 2.9.4 Blisters/ Delamination
>> - Acceptable - class 2,3:
>> . Two per side not exceeding 0.25 mm [0.00984 in] in the greatest
>> dimension.
>>
>> According to our understanding:
>> - If there are 3 bubbles and each of them is exceeding 0.25 mm in
> the
>> greatest dimension per side, this is defect.
>> - In case, if there are more than 3 bubbles and each of them is not
>> exceeding 0.25 mm in the greatest dimension per side, this is defect
> or
>> accept ???
>> Please help us understand clearly it.
>>
>> Thanks and best regards,
>>
>>
>> ***************************
>> Nguyen Hoang Luan
>> QC&Training Supervisor
>> Spartronics VietNam Co, Ltd.
>> No.3, Street No.6, VSIP
>> Th An Dist., BDuong Prov., VN
>> Tel: (84-650) 784 890
>> Fax: (84-650) 784 891
>> Mobile: 090.3.667448
>> Email: [log in to unmask]
>> ***************************
>>
>> ---------------------------------------------------
>> Technet Mail List provided as a service by IPC using LISTSERV 15.0
>> To unsubscribe, send a message to [log in to unmask] with following
> text in
>> the BODY (NOT the subject field): SIGNOFF Technet
>> To temporarily halt or (re-start) delivery of Technet send e-mail to
> [log in to unmask]: SET Technet NOMAIL or (MAIL)
>> To receive ONE mailing per day of all the posts: send e-mail to
> [log in to unmask]: SET Technet Digest
>> Search the archives of previous posts at:
> http://listserv.ipc.org/archives
>> Please visit IPC web site
> http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional
> information, or contact Keach Sasamori at [log in to unmask] or
> 847-615-7100
> ext.2815
>> -----------------------------------------------------
>>
>
> ---------------------------------------------------
> Technet Mail List provided as a service by IPC using LISTSERV 15.0
> To unsubscribe, send a message to [log in to unmask] with following text
> in
> the BODY (NOT the subject field): SIGNOFF Technet
> To temporarily halt or (re-start) delivery of Technet send e-mail to
> [log in to unmask]: SET Technet NOMAIL or (MAIL)
> To receive ONE mailing per day of all the posts: send e-mail to
> [log in to unmask]: SET Technet Digest
> Search the archives of previous posts at:
> http://listserv.ipc.org/archives
> Please visit IPC web site
> http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional
> information, or contact Keach Sasamori at [log in to unmask] or
> 847-615-7100
> ext.2815
> -----------------------------------------------------
>
> ---------------------------------------------------
> Technet Mail List provided as a service by IPC using LISTSERV 15.0
> To unsubscribe, send a message to [log in to unmask] with following text
> in
> the BODY (NOT the subject field): SIGNOFF Technet
> To temporarily halt or (re-start) delivery of Technet send e-mail to
> [log in to unmask]: SET Technet NOMAIL or (MAIL)
> To receive ONE mailing per day of all the posts: send e-mail to
> [log in to unmask]: SET Technet Digest
> Search the archives of previous posts at:
> http://listserv.ipc.org/archives
> Please visit IPC web site
> http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional
> information, or contact Keach Sasamori at [log in to unmask] or
847-615-7100
> ext.2815
> -----------------------------------------------------
>
> ---------------------------------------------------
> Technet Mail List provided as a service by IPC using LISTSERV 15.0
> To unsubscribe, send a message to [log in to unmask] with following text
in
> the BODY (NOT the subject field): SIGNOFF Technet
> To temporarily halt or (re-start) delivery of Technet send e-mail to
[log in to unmask]: SET Technet NOMAIL or (MAIL)
> To receive ONE mailing per day of all the posts: send e-mail to
[log in to unmask]: SET Technet Digest
> Search the archives of previous posts at:
http://listserv.ipc.org/archives
> Please visit IPC web site
http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional
information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100
ext.2815
> -----------------------------------------------------
>
---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 15.0
To unsubscribe, send a message to [log in to unmask] with following text
in
the BODY (NOT the subject field): SIGNOFF Technet
To temporarily halt or (re-start) delivery of Technet send e-mail to
[log in to unmask]: SET Technet NOMAIL or (MAIL)
To receive ONE mailing per day of all the posts: send e-mail to
[log in to unmask]: SET Technet Digest
Search the archives of previous posts at:
http://listserv.ipc.org/archives
Please visit IPC web site
http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional
information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100
ext.2815
-----------------------------------------------------
---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 15.0
To unsubscribe, send a message to [log in to unmask] with following text in
the BODY (NOT the subject field): SIGNOFF Technet
To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL)
To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest
Search the archives of previous posts at: http://listserv.ipc.org/archives
Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815
-----------------------------------------------------
|
