There are a lot of reasons not to trim these types of leads among them are
mechanical shock to the component, damage to the solder connection if
soldered in place (causes fractures during operational cycling), Exposed
base material (usually not copper for these), Damage to the board, etc.
Years past we had specific shear cutters that could perform an OK job on
leads such as DIPs without transferring as much shock to the component but I
would certainly not attempt their use on PGAs.
Mel Parrish
Soldering Technology International
Madison, AL
256 705 5530
256 705 5538 Fax
[log in to unmask]
-----Original Message-----
From: TechNet [mailto:[log in to unmask]]On Behalf Of Charles Caswell
Sent: Wednesday, October 17, 2001 3:47 PM
To: [log in to unmask]
Subject: Re: [TN] Trimming Leads...
If the pins are tempered they should not be trimmed. Also IPC 610 and
J-STD 001 say " should" a recomendation. If they don't cause a problem
in processing. Like catching on the fluxer at wave solder and do not
pose a problem mechanically in the end item you "should not" ( my
recomendation) have to trim. We don't unless specified on the
documentation except where the lenghth causes a problem later.
Charles Caswell
Process Lead, PCB
Frontier Electronic Systems
-----Original Message-----
From: TechNet E-Mail Forum. [mailto:[log in to unmask]]
Sent: Wednesday, October 17, 2001 4:58 PM
To: [log in to unmask]
Subject: [TN] Trimming Leads...
Hi All,
I've got a question about trimming leads on components such as three-row
DIN
connectors, machine pin sockets, PGA devices, things like that...
In the past, I've never trimmed the leads on components like that. But I
can't find any reference that says those are things that you don't lead
clip...
The reason I'm asking is the -610 and J-STD say that for class-3, the
leads
are not supposed to be longer than 1.5mm (.0591"). Should leads be
clipped on
the kind of components I outlined above if they exceed that?
Thanks!!
-Steve Gregory-
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