Hi there Chris, thanks for the reply,
What is puzzling me is,
These break off tabs, when manually broken off instead of getting a
depanelling machine
is the stress to the board, less than cutting an ordinary routed tab with
cutters?
Either way I can see the board stressed, and yes placement of ceramic caps
is thought about, but does
anyone know anywhere on the net where possible studies have been done on
breakoff tab stresses etc?
The reason I ask this is because we do not have (and I doubt if we would
get) a depannelling machine that
will break these tabs.
We do relatively small volumes and use FR4 only.
Most boards get scored where possible, but some have overhanging connectors
that need tabs instead
and I want to find out the very best method of supporting them in the panel.
Also, is there any spec on the ordinary tab, how thick the centre should be
etc?
Actually, thinking about it, if we were to get a depannelling machine, what
sort should we get?
Thankyou - Matthew Lamkin.
> -----Original Message-----
> From: [log in to unmask] [SMTP:[log in to unmask]]
> Sent: Tuesday, June 25, 2002 2:14 PM
> To: [log in to unmask]
> Subject: Re: [DC] How to break of IPC mousebyte breakaways ??
>
> Hi Matthew-
> Never saw a reply to this so I'll give it a go. My advice is; if your
> volumes are at all significant, don't do the by-hand or pliers thing
> unless
> you can lay the board out such that components, solder joints, and small
> traces, are REALLY far away from the breakaways. Especially X7R caps. We
> recently saw a problem where a cap more than 5MM from a breakaway
> sometimes
> cracked even though we were using special tooling for singulation. Turned
> out that it was happening during ICT due to flexing. Easy to fix at the
> ICT
> process but points out the potential for problems associated with
> breakaway
> tabs.
>
> Low tech material like CEM-1 will often delaminate badly around the
> breakaway if done by hand (or pliers).
>
> We use punch and/or shear tooling, routers, or Vscore, but all our stuff
> is
> pretty high volume.
>
> Lastly, I've never seen a plated hole used on a breakaway tab.
> Regards,
> -Chris
>
>
>
>
> Matthew Lamkin
> <matthew.lamkin@PR To:
> [log in to unmask]
> OTEC.CO.UK> cc:
> Sent by: Subject: [DC] How to
> break of IPC mousebyte
> DesignerCouncil breakaways ??
> <DesignerCouncil@I
> PC.ORG>
>
>
> 06/24/02 06:02 AM
> Please respond to
> "(Designers
> Council Forum)";
> Please respond to
> Matthew Lamkin
>
>
>
>
>
>
> HI there, can someone tell me please what is the best way to depanel a
> board
> that uses the
> IPC-782-3-31 Mousbyte breakaway?
>
> Is there a specific machine to do this or is it a case of a pair of
> Pliers/grips to snap it off?
>
> How "low stress" is this feature?
>
> Does "Thru XX PL" mean that they are to be NOT plated holes?
>
> Thankyou;
> Matthew Lamkin.
>
> --------------------------------------------------------------------------
> -------
>
> DesignerCouncil Mail List provided as a free service by IPC using LISTSERV
> 1.8d
> To unsubscribe, send a message to [log in to unmask] with following text in
> the BODY (NOT the subject field): SIGNOFF DesignerCouncil.
> To set a vacation stop for delivery of DesignerCouncil send: SET
> DesignerCouncil NOMAIL
> Search previous postings at: www.ipc.org > On-Line Resources & Databases >
> E-mail Archives
> Please visit IPC web site http://www.ipc.org/html/forum.htm for additional
> information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700
> ext.5315
> --------------------------------------------------------------------------
> -------
>
>
>
>
>
> "This e-mail message is intended only for the use of the named
> recipient(s).
> The information contained therein may be confidential or privileged, and
> its
> disclosure or reproduction is strictly prohibited. If you are not the
> named
> recipient, please return it immediately to its sender at the above address
> and destroy it."
>
> --------------------------------------------------------------------------
> -------
> DesignerCouncil Mail List provided as a free service by IPC using LISTSERV
> 1.8d
> To unsubscribe, send a message to [log in to unmask] with following text in
> the BODY (NOT the subject field): SIGNOFF DesignerCouncil.
> To set a vacation stop for delivery of DesignerCouncil send: SET
> DesignerCouncil NOMAIL
> Search previous postings at: www.ipc.org > On-Line Resources & Databases >
> E-mail Archives
> Please visit IPC web site http://www.ipc.org/html/forum.htm for additional
> information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700
> ext.5315
> --------------------------------------------------------------------------
> -------
---------------------------------------------------------------------------------
DesignerCouncil Mail List provided as a free service by IPC using LISTSERV 1.8d
To unsubscribe, send a message to [log in to unmask] with following text in
the BODY (NOT the subject field): SIGNOFF DesignerCouncil.
To set a vacation stop for delivery of DesignerCouncil send: SET DesignerCouncil NOMAIL
Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail Archives
Please visit IPC web site http://www.ipc.org/html/forum.htm for additional
information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315
---------------------------------------------------------------------------------
|
