I have found that the Class 2 length is typically the remaining length for
common through hole parts after insertion and solder.  Allowing the length
to remain without cutting (either in line with the wave or following hand
solder) eliminates MAJOR cost in terms of rework, touching up of fractured
solder, or having to maintain an inline cutter.

CAUTION:  Pure conjecture follows!
Our class 2 product is typically installed into systems that have less
chassis congestion - is it possible that the system design follows a
guideline as well relative to spacing of CCAs?  (That might be one reason).

The class 3 length brings back deja vu from military applications where it
was .06" max.

Jan Pelchat
Benchmark Electronics

> -----Original Message-----
> From: fullname [SMTP:[log in to unmask]]
> Sent: Tuesday, May 08, 2001 7:54 PM
> To:   [log in to unmask]
> Subject:      Re: [TN] IPC-A-610 Rev C - Question about wire/lead
> protrusion
>
> Hi, Bob,
>
> You hit this question which I was about to check with IPC, too. Any reply
> from your guys at
> IPC? I am dying to know the rationale too, :)
>
> Regards - Wee Mei
>
> Bob Hawkins wrote:
>
> > Please reference Section 5.2.7.1 -  Table 5-2
> >
> > What is the rationale on the (L) max numbers for Class 2  (2.5mm) and
> Class
> > 3 (1.5mm) ???
> >
> > Bob Hawkins
> >
> >
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