I disagree...
Every company is different. Weigh the cost vs benefits for your situation.
Try using a SS legend for the first few production runs then delete it after the PCB has been
"proven out". If a board requires a lot of manual adjusting or repair, leave it in.
In some cases the PCB is too tight to allow for a legible legend. It this case it is better to
force people to look at the assembly drawing and not a confusing legend.

Scott


Davis Ben wrote:

> I totally agree with Frank on this one.  Silkscreen legend is a
> "godsend" for those techs I've spoken with.  This is even more important
> as parts get smaller and closer together.  Finding a way to mark all
> parts is really tough on some boards - I've seen it add more than a day
> to the design cycle, but it usually saves much more than that over the
> life of the product.  Of course if you are designing "throw away" boards
> where no debug/repair is necessary, marking is not too much of an issue.
>
> We are currently using 50 mil text height with 8 mil thickness.  I've
> gone down to 35 mils with 6 mil thickness. We have no trouble with
> legibility - but we use 35 mils only when absolutely necessary.  With
> Mentor we are also able to regulate the aspect ratio so I usually cut it
> to 0.8.
>
> Mark on!!!!
>
> Ben Davis
> Systems & Electronics, Inc.
> [log in to unmask]
>
> Kimmey, Frank wrote:
> >
> > Now that there has been a couple of answers here is mine.
> >
> > I vehemently disagree with JoAnn and Mary on the necessity of silkscreen
> > legend. As a QA tool it is unbeatable and inexpensive (not to mention
> > the time saved in troubleshooting for rework/repair).
> >
> > We do high volume consumer (inexpensive, I would say cheap but that
> > sounds bad) products. We also put legend on all PCBs. Depending on the
> > type of design we use different text heights and weights.
> >
> > SMD (0805/SOIC) - I have used 35mil tall with 5mil wide lines, though I
> > prefer 42mil with 8mil lines. So far I have not experienced any
> > legibility problems.
> >
> > Leaded - I like 60mil tall with 8mil lines
> >
> > Call me if you want to discuss
> > Hope it helps
> > FNK
> >
> > Frank N Kimmey
> > EM Designer
> > C&K Systems, Inc
> > 916-353-5366
> > [log in to unmask]
> >
>
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