Subject: | |
From: | |
Date: | Wed, 09 Jul 1997 07:53:04 GMT |
Content-Type: | multipart/mixed |
Parts/Attachments: |
|
|
Tom makes an excellent reccomendation here - get rid of your silkscreens!
I have struggled with this cultural change he describes while working within a major automotive company. The resistance to the change was based on two premises 1) manual insertion operators would increase the number of misinsertions and 2) troubleshoot/repair persons would have difficulty in locating features. I would argue that suppling the persons with "maps" of component locations is sufficient. Especially in the case of large volumes, after building 20,000 units - the insertion people surely know where their five components go.
Jamie McIntyre
Field Application Engineer
PCI
-----Original Message-----
From: mailnet
Sent: Tuesday, July 08, 1997 11:28 PM
To: Jamie W. McIntyre
Subject: [log in to unmask]: RE: FAB: Silkscreen
From: [log in to unmask]
Tom:
We work to a stated minimum character height of .040"
and thickness of .008". We also perform an "autoclip" of
the nomenclature, which obliterates any silkscreen
characters that fall within .008" of a solderable feature,
due to silkscreen tolerancing. Yes, "R"s sometimes end up
looking like "P"s, and "B"s like "3"s. This is why I have
been encouraging my customers for years to eliminate
silkscreen if possible. An added benefit to eliminating
legends is a cost savings of about $1/panel per side (divide
by # up per panel for piece price savings). I realize that
eliminating silkscreens requires a culture change, to say
the least, but most designs of late do not afford the real
estate necessary to screen these alpha-numerics onto circuit
boards with any degree of legibility. Many folks are
designing a different shaped pad for pin 1 (a square) in the
etch pattern for component orientation.
Tom Coyle
Field Services Engineer
HADCO Corporation
***************************************************************************
* TechNet mail list is provided as a service by IPC using SmartList v3.05 *
***************************************************************************
* To subscribe/unsubscribe send a message <to: [log in to unmask]> *
* with <subject: subscribe/unsubscribe> and no text in the body. *
***************************************************************************
* If you are having a problem with the IPC TechNet forum please contact *
* Dmitriy Sklyar at 847-509-9700 ext. 311 or email at [log in to unmask] *
**********************************
****************************************
|
|
|