Howard:
From your information that this disturbed looking joint
appears during the second reflow, it shows that it has to do with the
plating of the lead of the diode. Some metal is leaching through and
surfacing and making that appearance. You can make some experiments, such as
soldering the components and glue them to a scrap board and heating them up
with a heat gun once or twice and inspect each time to duplicate the
phenomena.
Regards,
Ramon
> -----Original Message-----
> From: Howard Watson [SMTP:[log in to unmask]]
> Sent: Tuesday, September 02, 2003 6:08 PM
> To: [log in to unmask]
> Subject: Re: [TN] pic's
>
>
> Hi all,
>
> I work with Lance and he just signed on to the TechNet. I guess that
> means he gets a "free" attachment pass. The odd thing about what we are
> seeing with these diodes is that:
> 1) The problem occurs with diodes only from ON Semiconductor.
> 2) On some diodes, the solder joint on one lead is nice and shiny, like
> all the others on the board, but the other lead will have the "disturbed"
> look. It occurs inconsistently among the 9 ON diodes on the board.
>
> Several different reel lots were evaluated, with no difference. A reel
> was sent to ON for solderability testing, and not surprisingly, the
> results came back with no solderability problem (they only tested 5
> components).
>
> If this were disturbed soldering, how could this show up only on a diode
> and only from one manufacturer (there are several diodes from other
> Mfg'rs)?
>
> Some other points to note: this is the 2nd side of reflow with 300
> components, it's on a chain conveyor, there are two cooling zones in the
> 10 zone oven. Thanks for the feedback.
>
> Howard Watson
> SMT Manufacturing Engineer
> AMETEK/Dixson
>
>
>
> Carlr Ray <[log in to unmask]>
> Sent by: TechNet <[log in to unmask]>
>
> 09/02/03 02:18 PM
> Please respond to "TechNet E-Mail Forum."; Please respond to Carlr Ray
>
> To: [log in to unmask]
> cc:
> Subject: Re: [TN] pic's
>
>
>
> Lance,
> Couple of questions for you.
> 1. Does the product ride through the oven on a conveyor (grid or belt),
> or is it a rail system?
> 2. Has anyone checked to make sure the transport method (grid/belt or
> rail) is operating correctly and not jerking or causing movement of the
> product during reflow?
> 3. Does you reflow oven have a cooling section? If so is it possible
> that it is cooling the units to quickly?
>
> Sorry I don't have any suggestions but I do agree with a previous email
> that is appears as though the components were disturbed during the
> reflow process. I do not see any solder defects but I do think that this
> could lead to defects if the problem is not corrected.
>
> >>> [log in to unmask] 9/2/2003 2:16:06 PM >>>
> I have attached some pictures of components that always seem to have
> one
> joint that is not soldered as the other end. These happed mainly with
> this component at various sites on the board. Is this a contamination
> a
> disturbed joint or a cold joint. This is an SMT process and the
> problems
> vary
> on the runs. I would like to know if this is a defect for class 2 or
> not.
>
> Thanks in advance for your time.
>
>
> P. Lance Mayes
> Mfg. Trainer
> ----- Forwarded by Lance Mayes/CO-GRA/Ametek on 09/02/03 01:07 PM
> -----
>
>
> Howard Watson
> 08/27/03 05:33 PM
>
>
> To: Lance Mayes/CO-GRA/Ametek@Ametek
> cc:
> Subject: pic's
>
>
>
> Howard Watson
> SMT Manufacturing Engineer
> AMETEK/Dixson
>
> ---------------------------------------------------
> Technet Mail List provided as a service by IPC using LISTSERV 1.8e
> 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
> 847-509-9700 ext.5315
> -----------------------------------------------------
>
> ---------------------------------------------------
> Technet Mail List provided as a free service by IPC using LISTSERV 1.8e
> 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
> 847-509-9700 ext.5315
> -----------------------------------------------------
>
>
---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 1.8e
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 847-509-9700 ext.5315
-----------------------------------------------------
|
