Subject: | |
From: | |
Reply To: | TechNet E-Mail Forum. |
Date: | Mon, 29 Jun 1998 09:08:35 -0400 |
Content-Type: | text/plain |
Parts/Attachments: |
|
|
Your note suggests that ALL components may become surface mount, but as far
as the connector is concerned, perhaps this design may be an "ideal"
candidate for intrusive reflow: keeping the connector as a through hole
component processed through a reflow environment. The decision may be based
on what type of connector this is.
Do you have a shielded I/O connector (higher mating/unmating forces)? Is it
a high pin count (higher mating/unmating forces)? Is it a tin (versus gold)
interface (higher mating/unmating forces)? Is it a "right angle" board
connector (higher shear stress)? All of these will affect the stress/strain
on the solder joints. If you do go the surface mount route, I'd keep some
hold downs on the design.
Martha Rupert
AMP Incorporated
email:[log in to unmask]
> -----Original Message-----
> From: Michael Lang [SMTP:[log in to unmask]]
> Sent: Sunday, June 28, 1998 9:35 PM
> To: [log in to unmask]
> Subject: [TN] HELP: Cracking Discretes on PCB's
>
> Hello Technetters,
>
> I have a PCBA which has been built in PTH configuration with great
> success for years. However, due to the need for increased functionality
> in the same form factor, it seems that it is time to convert the PCBA to
> SMT format.
>
> My main concern relates to PCB flex and solder joint integrity...
>
> The PCBA is about 4" x 6". It is held along its 4" sides in a rack. A
> cable is plugged into the card via a connector along the top 6" side of
> the PCB (NOT a card edge connector, but PTH connector which means you
> push against the FACE of the PCBA. I do not know the force, but the PCB
> DOES flex significantly. Plus, since this is a home / contractor
> product, it does not get handled gingerly...
>
> THE PRIMARY CONCERN: Inducing cracks in either the components or solder
> joints of leadless surface mount components.
>
> What information exists with respect to this subject?
>
>
> What testing makes sense? What has been done already by others?
>
>
> Any help is appreciated.
>
> Thanks,
>
> Michael Lang
> [log in to unmask]
>
>
> ps. Hi RH!
>
> ______________________________________________________
> Get Your Private, Free Email at http://www.hotmail.com
>
> ################################################################
> 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 web site (http://jefry.ipc.org/forum.htm) 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 web site (http://jefry.ipc.org/forum.htm) for additional information.
For technical support contact Hugo Scaramuzza at [log in to unmask] or 847-509-9700 ext.312
################################################################
|
|
|