Hi,
I spent a LOT of time on this, some thoughts:
1. About CAD apps not supporting more than one vendor PN per item:
So True. CAD libraries are not very good database managers. Not the focus
for them. I have a single resistor in my schematic lib, the single standard
shape works for 0201 through 100watt. Caps I have 2 shapes, one polarized
and on regular. In PCB tools I have standard 0402, 0603, 0805, 1206 and 2515
footprints. So with this small handful of cad symbols I cover what, a couple
million parts? All the linkages (Atttributes for library folks) are in a DB.
I started with a P&V library long ago and built around it. As P&V closed
shop (real shame, it was a great product) I expended my functions am I now
and quite independent and don't use P&V now days.
The concept of an "Approved Vendor List" for a part idemands an internal
part number (or something) that all these Vendor, Manf, Vendor PN and Manf
PN can be linked to. And each of those entries need multiple cost entries.
(Prices at 1, 10, 100 and 5K for example). If you think that can be built in
a spread sheet environment forget it.
The selection of a parts based on availability / price is different than
defining a part for use in a circuit. Typically two different business
functions.
And it gets even more complicated when you have one assembly using another
assembly.
And you want to use "Surrogate Keys" as you build this puppy. This way you
can play with changing parts numbers without breaking lists at least in the
DB.
2. Engineering data is important just as procurement data is important.
There are two big items, PCB Foot prints and datasheets. These are pretty
well matched for assigning to a company part number. You need to find thens
so search engines are required.
3. Stocking and finding things
I do a lot of engineering and might build 25 or 250 boards here and there. I
need stock for engineering purpose and then assembly stock. Engineering
stock with loose parts is nice but all assemblers want reels. So you end up
with multiple storage types. Add to this kits. I typically will build X
boards and all those parts go into a KIT. I like keeping track of what was
in kits when as when I need a part I often go grab something from a previous
old kit.
I did a lot of playing with what I call "Sort Codes" for managing the
location and storage of parts. Finally got one that seems to work well.
If anyone is interested they can look at www.partsync.com. I am delighted to
share what I know.
Bob K
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Decker, Scott UTAS
Sent: Wednesday, June 01, 2016 1:58 PM
To: [log in to unmask]
Subject: Re: [TN] Part numbering, MRPs & reality
Ken,
Humm, old guy using the "We always do it this way, it works" method...
Well, it seems that ECAD designers are all the old guys, (self-included)
these days according to the surveys that say the industry is growing old
with less "new / younger" ways... :-) Anyway, to your question and some
things to think about. We here, (and at other companies I've been at)
started out using parts on BOM's with vendor part numbers to make it easy to
order parts, etc. At issue is most, (and I can only speak for the tools we
use, MGC) CAD tools don't allow more than one part number per part. Where
the trouble comes in is if you use a specific vendor part number on your BOM
and you send it to a contract manufacture for assembly and they furnish the
parts, what happens when they can't get the specific part you call out
because it's on a 6 inch reel but they have 8 inch reels of those parts all
over? Or, Kemet is 6 weeks out, but Vishay is stocked at the distributor but
the part numbers are not the same? We tried using a place holder to indicate
that the CM could substitute the place holder with which ever reel or other
"don't care" information but that didn't work either. When assemblies came
in and are run through First Article Inspection, the BOM may not reflect the
true part number(s) used to build since a different vendor or packaging part
number, (which may be 100% compatible with the exception of packaging or
some other don't care aspect) was used. You are on the right path in my
opinion, to have a company part number issued to each part and allow the
company part number to call out all the manufacturer's part numbers or
usable number combinations, so that the BOM will always match the assembled
board and your component suppliers are covered when it comes to how they are
ordered, etc. Every place I've worked at, with few exceptions, has changed
their system when they started finding out that CAD systems and multiple
part numbers for parts just don't play well together sometimes. Sorry for
the long answer, (I'm known for that here... :-) ) but I thought it might
help to have a few opinions and experiences from others in your court... :-)
Good Luck! BTW, Sounds like you should check into a new turnkey outfit
while you're at it???
Scott Decker - Senior Analyst, Drafting & Design Services CID+ - Electronic
Systems Center UTC AEROSPACE SYSTEMS
3445 S. 5th Street, Suite 170, Phoenix, AZ 85040 U.S.A.
Tel: 602 308 5957 FAX: 602 243 2347
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-----Original Message-----
From: TechNet [ <mailto:[log in to unmask]> mailto:[log in to unmask]] On Behalf
Of Ken Barton
Sent: Wednesday, June 01, 2016 9:02 AM
To: <mailto:[log in to unmask]> [log in to unmask]
Subject: [External] [TN] Part numbering, MRPs & reality
Greetings TechNet gurus,
Just arrived at my present employer charged with creating process for
PCB/CCA libraries. We have a turnkey layout vendor, this relationship is
somewhat problematic: Wrong footprints & component subs. We have absolutely
no correlation with Orcad CIS & our MRP/ECAD system. All board components
are using vendor PNs. So, I want to toss this out to all for a reality
check: My experience over a wide range of OEMs I have worked for is to issue
each component a "Company" 10 digit PN. All critical attributes will be
entered & fall into CIS explorer. The MRP/ECAD we have has all capability
for handling the mechanical AND electrical assy structures. As my employer
is the first time I have seen vendor PNs go on EBOMs & released out into the
wild, I've been informed that other huge companies have done the same.
Am I just an old guy using the "We always do it this way, it works?" I am
willing to hear the pros & cons, has anybody else been in the middle of
this?
Ken Barton
Technical Designer,
Vehicles & GSE/
Avionics HW
Blue Origin, LLC
21218 76th Avenue S.
Kent, WA 98032
(253) 437-5625 x625
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