Chill out....
There IS a standard that explains how components are loaded onto reels,
EIA-214 or something, I'll check when I get home.
(but I don't know why you attack ONE PERSON in a DISCUSSION for not
providing the exact answer that YOU PERSONALLY want to get. Are you new?)
-----Original Message-----
From: Paul Arklay [SMTP:[log in to unmask]]
Sent: Wednesday, September 23, 1998 5:26 PM
To: [log in to unmask]
Subject: [DC] Jedec standard EIA-JED-95 not relevant for smt
polarised components?
Hi Everyone,
Barry Olney wrote:
>We changed our component orientation, years ago, to pin 1 - top
right in
>order to comply with our European technology partners.
Who is "we" ?
Was this ever published as a standard by a governing body?
Which European technology partners?
It great to generalise about something that supposedly occurred
years ago
but how about some facts.
>There are many Jedec standards at URL http://www.jedec.org I
thought
>the issue in question was covered in the EIA-JED-95 standard?
I have looked at this standard on Barry's recommendation and cannot
see that
it covers this issue at all. It is a mechanical standard for
component
outlines and does not include all polarised components anyway.
It's great to quote standards but one should see if they are
relevant to
this issue first.
As far as I can see there is not an official standard for this issue
and the
industry has therefore created its own default standard with pin1 to
the
bottom left as seen in the majority of responses to my original
question
which was sent also to the Mentor Uers Group and Cooper and Chyan
Technology
user group.
Best Regards,
Paul Arklay
Paul Arklay
PCB Design Engineer
JTEC Pty Limited
Unit 3 118-122 Bowden Street
Meadowbank NSW 2114
Australia
Direct +61 2 93900622
Fax +61 2 93640055
Switch +61 2 98096933
Email: [log in to unmask]
Barry Olney wrote:
>You are right Jack in that we need to create our libraries and use
>design rules to suit the end process.
>
>We changed our component orientation, years ago, to pin 1 - top
right in
>order to comply with our European technology partners.
>
>There are many Jedec standards at URL http://www.jedec.org I
thought
>the issue in question was covered in the EIA-JED-95 standard?
>
>Cheers,
>
>Barry Olney
>
>Olson, Jack C wrote:
>>
>> Well, SOMEONE is missing the point.... <grin>
>>
>> Yes, you can create stuff any way you like, but since he has a
CHOICE
what
>> orientation to build them, and since it doesn't matter to the CAD
operator
>> what orientation they are, it seems logical and intelligent to
wonder if
the
>> ASSEMBLER might have a preference, eh?
>>
>> If you build a library component and plop it into your design,
and don't
>> rotate it, at the end of the design cycle when you create your
pick and
>> place files for the assembler, that component will be listed as
zero
degrees
>> rotation, right? If you build a SMT resistor vertically, no
matter how
you
>> rotate it in the database, the rotation in the data file will be
useless
>> because SMT resistors are packaged horizontally on a reel. The
operators
>> know this, so they check rotations before they start, but
wouldn't it be
>> nice if we could get MOST OF THEM right in the library? Sometimes
you
can't
>> because some ICs come on reels horizontally, and some come
packaged in
>> sticks and come out vertically, so you have to modify some
rotations no
>> matter what. But all I am saying is that if you know what your
vendor is
>> using, why not make it easy for him and TRY to supply good data?
>>
>> Still, you can never win... here at Intel we are asked NOT to
place
>> components in the same orientation as they come on the reel,
because the
>> type of pick-and-place machine we use rotates the head 180
degrees as it
is
>> moving from the reel to the board, and then will have to rotate
another
180
>> to get back to the same orientation, which wastes a whole tenth
of a
second
>> (perish the thought!). So, you can never learn enough in this
business,
>> right?
>>
>> Onward thru the fog, Jack
>>
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