TECHNET Archives

September 1998

TechNet@IPC.ORG

Options: Use Monospaced Font
Show Text Part by Default
Show All Mail Headers

Message: [<< First] [< Prev] [Next >] [Last >>]
Topic: [<< First] [< Prev] [Next >] [Last >>]
Author: [<< First] [< Prev] [Next >] [Last >>]

Print Reply
Subject:
From:
"Stephen R. Mikell" <[log in to unmask]>
Reply To:
TechNet E-Mail Forum.
Date:
Thu, 3 Sep 1998 11:18:58 -0500
Content-Type:
text/plain
Parts/Attachments:
text/plain (32 lines)
A couple of things to consider..

1. Is the lead of the dip firmly seated on the topside of the PWB, the
shoulder where the dip lead widens is in contact with the laminate.  If it is,
the there is no stress relief between the the top of the PWB to the solder
joint during thermo-cycling.

2. Thermo-cycling of such a limited design will probably result in the failure
of a number of conventional part styles that assume a plated thru hole design
is used.  Any part which seats on a stepped portion of the lead will likely
crack the solder fillet.  The full solder joint using a plated thru hole is
not only about 7 times stronger than the pad only design of single sided
boards, but solders the area from the pad to the stepped area of the lead,
eliminating the stress.

Good luck,
Steve Mikell
SCI SYSTEMS
Plant 13

################################################################
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
################################################################


ATOM RSS1 RSS2