Yes I did and have been pleased since 1997 originally I bought the smt
library made for Protel and have been adding to it ever since. Recently
I purchased the "Land Patterns Made Simple" to gain a further insight
into the subject. (This is something Protel could incorporate into their
package) SMTPlus has created  a footprint Library generator now but it
does not work with Protel that does not mean you couldn't use it, just
that it can't create the footprint directly into protel. 

The IPC footprints are way to generous covering too many "ifs" and
"buts" and not updated regularly - Jim Blankenhorn owned his own
Assembly plant and keeps up with the latest information. Honestly as a
small service bureau there isn't a lot of extra time for footprint
research and feed back is not the same as in house work. Jim has served
me well over the years and customers have been pleased with the assembly
results.

Fran Wheeler

-----Original Message-----
From: Dennis Saputelli [mailto:[EMAIL PROTECTED] 
Sent: Thursday, March 11, 2004 11:07 AM
To: Protel EDA Forum
Subject: Re: [PEDA] SMTPlus Common PCB footprint specifications


we looked at SMTPlus
but as i understood it, they don't do protel

did you have to create the footprints from dwgs?

Dennis Saputelli


Frances Wheeler wrote:
> 
> I have been using SMTPlus for years for footprints 
> http://www.smtplus.com/  they have the expertise and my customers have

> always been pleased with the production results. They will develop a 
> new footprint quickly and get it back to you the same day. Check it 
> out they have saved me lots of time and therefore lots of money. Fran
> 
> -----Original Message-----
> From: Leo Potjewijd [mailto:[EMAIL PROTECTED]
> Sent: Wednesday, March 10, 2004 5:24 PM
> To: Protel EDA Forum
> Cc: [EMAIL PROTECTED]
> Subject: Re: [PEDA] Common PCB footprint specifications
> 
> At 10-03-04 18:36, Ray Mitchell wrote:
> >I'm sure this is a repeat, but is there a simple specification 
> >readily available that gives the "commonly accepted" (if there is 
> >such a thing)
> 
> >dimensions for 0402, 0603, ..., SIOC-14, etc., and all the other 
> >"standard" footprints?  I don't really want to wade through a bunch 
> >of technical stuff to derive all of this myself and I certainly don't

> >want
> to
> >trust a priori the patterns that come with Protel or any other 
> >product.  It's really annoying when part manufacturers don't provide
> these
> >footprints, assuming they are common knowledge.
> 
> Others have already refrenced the s'standards' (IPC). I'm a little 
> more sceptical.....
> 
> To my knowledge, there is no such thing as a standard footprint.. Was 
> it not the CEO of Sun Micro Systems who said at one time "I just LOVE 
> standards, because there are so many of them".
> 
> In short, even a simple shape such as a 0805 is implemented 
> differently by different manufacturers.
> Weird? I'd say so. Surprising? Not really: OUR wheel is MUCH
> rounder.....
> New and improved...... New formula......  You know the buzz.
> 
> I use a spreadsheet (not ready for the public yet, but I'll post it 
> sometime in the not-so-distant future to the Yahoo list) to calculate 
> a footprint from the dimensions and tolerances of the component given 
> by the mfgr. The differences are sometimes quite large (as in: HUGE); 
> in fact so
> large that a component from anoher  mfgr will not fit  on the same
> footprint (we lost a complete production run on that one).....
> 
> I'd still say to look up the mfgr datasheets (whenever available) and 
> derive your own footprints from that information using a combination 
> of guidelines (IPC, JEDEC) and common sense, seasoned with a tuch of 
> practicality (you don't want 73 mils distance on 0805 pads when you're

> using a 5 mil grid). Hey, I even round off pad sizes that were 
> designed in mm to an integer number of mils.....and I'm in the metric 
> part of the world ;-) Find values (IPC, JETEC, your own fab house) for

> things like placement accuracy, heel and toe solder fillets and ask 
> your board stuffer what component clearances (and directions) are 
> needed for what processes and machines they use.
> All of these (and then some) will influence the final optimum
> footprint...... Last but not least: small series (50+) can most of the
> time get away with
> minor deviations from optimum, big series (500+) usually can not, huge
> series (10k+) never can.
> 
> A lot of work, yes, but one only uses so many different 
> components......
> 
> I found it worthwile to invest the effort: I have no production 
> failures
> 
> yet on my boards (apart from that one that was designed for Philips 
> TSOP
> 
> and could not accomodate Fairchild).
> BTW, I am designing boards for just 10 years now, so I really don't 
> know
> 
> much about the subject yet. In fact, I'm still learning, every single 
> day.....
> 
> To qoute another frequent poster to this list: "I hope this helps".
> 
> Regards,
> 
> Leo Potjewijd
> hardware designer
> Integrated Engineering B.V.
> 
> [EMAIL PROTECTED]
> +31 20 4620700

-- 
_______________________________________________________________________
Integrated Controls, Inc.           Tel: 415-647-0480  EXT 107 
2851 21st Street                    Fax: 415-647-3003
San Francisco, CA 94110             www.integratedcontrolsinc.com







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