Hi Fred;
You do againg.....!!!! what is a PSB????.....or a Design!!!.... or a RE-job
openingssssssssss placemnt!!!!..............
X-UIDL: 827840690.010
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Date: Mon, 25 Mar 1996 18:59:47 -0600
To: [log in to unmask]
From: [log in to unmask] (Fred Pescitelli)
>"All PCB's shall be finished with deep color anti-mildew flame plating on
>which circuitry connections are drawn"!!!!
>
Rubens,
Where did you find this???????
Sears sells some anti-mildew additive in their paint dept. HeHeHe.
Regards
Fred Pescitelli
Phoenix Designs
4602 Montauk Rd.
Lilburn, GA 30247
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Hi is for you all,.... this the answer I'm looking!!!....
X-UIDL: 827840690.002
Date: Mon, 25 Mar 1996 17:09:00 +0000
From: [log in to unmask] (Greg Kaskey)
Subject: RE: Board Specification
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Rubens,
I talked with Peter Malinaro at NTI and he said he has not heard of that
terminology ("All PCB's shall be finished with deep color anti-mildew flame
plating on
which circuitry connections are drawn"). But after talking a little more it
MIGHT be similar to the organic solderability preservative (OSP).
---the following was taken from "Printed Circuits Handbook", fourth edition,
by Clyde F. Coombs, Jr.---
19.24.7 Organic Solderability Preservatives (OSPs)
The OSP processes (also known as prefluxes) are applied to bare copper
surfaces after solder mask, Generally, these flat surfaces provide reliable
solderability after thermal excursions such as adhesive curing, solder past
reflow, and wave soldering, and provided they are adequately protected from
oxidation, The OSP must be thermally stable and provide corrosion
protection.
Options for OSP systems include chemistry based on substituted azoles and
rosin/resin bases. The coating can generally be applied in immersion ,
spray, or flood mode. The coatings must bind to copper, prevention humidity
and high temperatures from degrading solderability, and must be compatible
with no-clean assembly fluxes. Proper surface preparation of the boards is
required for OSP coatings to be effective. An alternative to this process
is the use of benzotrizole. However, this is an extremely thin coating
which gives very limited protection against oxidation and moisture.
Improved protection can be achieved by following the benzotrizole step with
a posttreatment of a preflux. The preflux will prevent moisture
penetration. Both solvent-based and water-based prefluxes are available.
19.24.8 Comparison of Coatings
The following points should be considered when deciding on alternative
coatings previously described.
1. Ease of assembly. Fine-pitch technology may require immersion tin or
other electroless plating systems. Mixed technology boards may be better
suited for OSP coatings.
2. Rework and Handling. OSP coatings are the easiest to rework but are the
most fragile compared to metallic systems. OSPs can be removed with organic
solvents or with 5% hydrochloric acid if the OSP is a water-based structure.
3. Shelf life. The shelf life of immersion, electroless plated, and OSP
coatings is not as long as that of leveled or fused solder surfaces.
Storage time should be kept to a minimum for alternative coatings.
Thanks,
Greg Kaskey
----------
From: Rubens Fiuza Lima
To: KASKEYG; internet!oadc.com!dfrindt
Subject: Board Specification
Date: Mon, Mar 25, 1996 2:19PM
>X-UIDL: 827781284.000
>Date: Mon, 25 Mar 1996 14:07:52 -0500
>X-Sender: [log in to unmask]
>Mime-Version: 1.0
>To: [log in to unmask]
>From: [log in to unmask] (Basil Perez)
>Subject: Board Specification
>Cc: [log in to unmask]
>
>>X-UIDL: 827532891.000
>>Date: Fri, 22 Mar 1996 17:10:08 -0500
>>X-Sender: [log in to unmask]
>>Mime-Version: 1.0
>>To: Basil.Perez
>>From: [log in to unmask] (Shu Shen Sun)
>>
>>Basil :
>>
>>The following is the quote. Thank you for your help.
>>
>>"All PCB's shall be finished with deep color anti-mildew flame plating on
>>which circuitry connections are drawn"
>>
>>
>>
>
>
>
Thank you,
Greg Kaskey
[log in to unmask]
From
Rubens Fiuza Lima
[log in to unmask]
|
