Hi,
I had this kind of problem in the past. The problem were related with
glue specifications. The lot of glue had to be changed in order to solve
the problem, at that time we used a torque test to measure the force of
component atachement to the board. When the problem is generic ( All
kind of components , SOT packages are more sensitive ) the first thing
is chek glue dot diameter, then oven profile and if its OK is very
probably that you have glue problems. Try to change the glue lot.
Other time we had the same problem but were related with solder mask
of the board, when the falled components were checked you could see
solder mask atached to the glue and the component, we had to contact the
board supplier to solve the problem.
Bye
> -----Original Message-----
> From: Stephen R. Gregory [SMTP:[log in to unmask]]
> Sent: 18 de Março de 1999 21:40
> To: [log in to unmask]
> Subject: Re: [TN] Bottom side parts falling off during wave
>
> In a message dated 3/18/99 3:54:47 PM Pacific Standard Time,
> [log in to unmask]
> writes:
>
> << Hi folks,
>
> I am looking for inputs on a long-standing problem encountered in our
> shop:
> Bottom-side
> parts (passives) falling off in the Wave...where the only remnants of
> the
> part is a flattened glue
> dot of proper diameter and volume, and sometimes flux residue (from
> the
> wave).
>
> I suspect there is some incompatibility between one of our pastes and
> the
> glue. Our shop
> uses two types of paste and one type of glue. After some
> experimenting, I am
> seeing a
> STRONG correlation that suggests one paste type is not suited to the
> glue.
>
> Short of listing the specific materials used and getting myself in
> trouble,
> is there anyone who
> has encountered the problem I am talking about? What was the cause
> and how
> did you
> resolve it?
>
> If you want more specifics, please call me at 509-921-4311.
>
> Thanks,
>
> Earl & Marc >>
>
> Hi ya Earl (and Marc)!
>
> Hey pardner! Where were ya' for the expo? Was lookin' forward to
> seeing if
> you're uglier than me (GRIN) But from the sounds of things, looks like
> you're
> kinda' up to your keester in alligators...probably couldn't afford the
> time
> away huh?
>
> Anyways, are the parts that are falling off all the same part? Or
> are they
> all different ones? If they're all the same, the time that something
> like that
> happened to me was because of the mold release compound they used when
> making
> the tape for the components, got all over the caps we were using and
> the glue
> didn't wanna stick to em'... ...got components from a different vendor
> and
> everything was okie-dokie after that. But knowing murphy, it ain't
> gonna be
> that simple for you...but just maybe it might.
>
> C-ya L8'er 'gator!
>
> -Steve Gregory-
>
> ################################################################
> TechNet E-Mail Forum provided as a free service by IPC using LISTSERV
> 1.8c
> ################################################################
> To subscribe/unsubscribe, send a message to [log in to unmask] with
> following text in the body:
> To subscribe: SUBSCRIBE TechNet <your full name>
> To unsubscribe: SIGNOFF TechNet
> ################################################################
> Please visit IPC's web site (http://www.ipc.org) "On-Line Services"
> section for additional information.
> For technical support contact Hugo Scaramuzza at [log in to unmask] or
> 847-509-9700 ext.312
> ################################################################
################################################################
TechNet E-Mail Forum provided as a free service by IPC using LISTSERV 1.8c
################################################################
To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body:
To subscribe: SUBSCRIBE TechNet <your full name>
To unsubscribe: SIGNOFF TechNet
################################################################
Please visit IPC's web site (http://www.ipc.org) "On-Line Services" section for additional information.
For technical support contact Hugo Scaramuzza at [log in to unmask] or 847-509-9700 ext.312
################################################################
|
