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From:
"Glidden, Kevin" <[log in to unmask]>
Reply To:
TechNet E-Mail Forum <[log in to unmask]>, Glidden, Kevin
Date:
Fri, 12 Mar 2010 10:35:50 -0500
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Perhaps one of my favorite "Dilbert" strips is when the design engineer states to his boss "we need to add this $3 component to the design to comply with federal regulations", to which the boss answers "This has to be reviewed for cost justification", and the next panel is the engineer standing in front of the managers and pointing to the chalkboard, on which she has written the word "DUH" to the power of infinity and is stating "and you know it's accurate because I used MATH".

Hard to visualize in description only, but a really great one none the less.

Kevin

-----Original Message-----
From: Glidden, Kevin [mailto:[log in to unmask]] 
Sent: Friday, March 12, 2010 9:52 AM
To: [log in to unmask]
Subject: Re: [TN] fungus question

Is it sick that I find great humor in this thread?

What an ironic truth.........

-----Original Message-----
From: Douglas Pauls [mailto:[log in to unmask]] 
Sent: Thursday, March 11, 2010 5:15 PM
To: [log in to unmask]
Subject: Re: [TN] fungus question

Ohhhhh, I beg to differ.  Well, not actually beg, I have some pride.

At the box level, I may (and usually do) have all of my assemblies coated 
with a conformal coating that places a barrier between an external fungus 
and my component.  Now, if I am using a MIL-I-46058 qualified coating, 
which I do, I know that this is fungus resistant, or at least non-nutrient 
because that is part of the qualification procedure. 

Which means, that if I have a box level qualification needing fungus 
resistant, I don't have to worry about component level fungus resistance 
IF I conformally coat.  What about if the designer does not want to use 
conformal coating?  Foolish, but it happens.  Then we have to go back down 
to the component level for fungus resistance.

I would agree with your qual person in that I have not seen fungus eat a 
modern component.  I think this is a holdover from the era of the 
dinosaurs.  But my technical opinions may mean nothing when I have a 
customer asking me why a requirement was not met, real or imagined. 

Perhaps you have better suppliers than I do but the vast majority of our 
component vendors are silent on fungus resistance.  Its not on the data 
sheets.  Very seldom is that test ever done on component materials (I 
checked with some of my lab friends), so if they are certifying as fungus 
resistance on faith.  Hallelujah, praise the Lord.  It is an expensive 
test that needs qualified people to run it.  Ask your local independent 
lab what it cost to handle biologically active materials.  Then be 
thankful you ain't  them.

I really love how this cost avoidance or cost transferrence system works. 
The big customer does not want to tackle the issue, so they put it in the 
system requirements to us.
The program manager does not want to pay for the testing, so they try to 
do "qualification by analysis", which is a fancy way of saying a SWAG. 
So they pass the buck to the cognizant design engineer. 
The cognizant design engineer is usually a mechanical or electrical 
engineer, and what do they know about microbes. 
So it gets passed down to our component application engineers. 
They don't really want to pay for the testing, so they push back to the 
component vendors.
We regularly beat the hell out of component vendors, standing in righteous 
indication when they claim we have beat all the profit out of the system. 
What?!! The Joy of dealing with our Corporation is not enough for you?!!!! 
Some People.
Since the component people don't regularly do this test, would be happy to 
do it for us, for a nominal fee.  Which is passed to the application 
engineer, to the cognizant design engineer, to the program manager, who 
does not want to pay for it. 
And in the grand scramble, the question goes unanswered, but everyone 
feels good because they pursued the question. 

How the hell did I get up on this stump?

Doug Pauls



"Kane, Joseph E (US SSA)" <[log in to unmask]> 
Sent by: TechNet <[log in to unmask]>
03/11/2010 03:34 PM
Please respond to
TechNet E-Mail Forum <[log in to unmask]>; Please respond to
"Kane, Joseph E (US SSA)" <[log in to unmask]>


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Subject
Re: [TN] fungus question






Wewease Dougwas.

If fungus testing is done at box level as part of qual (which
I think is typical), then it will necessarily check for
both cases 1 and 2 that you describe.  I checked with our qual 
guy, and he never of fungus growing on a plastic part.  But he
thinks that component manufacturers typically specify
plastic that is certified non-nutrient.

-Joe

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Douglas Pauls
Sent: Thursday, March 11, 2010 3:02 PM
To: [log in to unmask]
Subject: Re: [TN] fungus question

Inge,
I am too Norwegian to be Roman.  Though it did bring to mind a sketch from 
Monty Python's Life of Brian.

I asked the question originally because many of our government contracts 
and purchase orders, call out requirements, often from similar purchase 
orders from 5 years before, which were based on templates from 5 years 
before that, based on military standards last updated 5 years before that. 

 You may have a requirement chain that leads back to something like 
MIL-STD-454.

There are two subtle differences to the fungus resistance question: (1) do 
the materials of construction contain items which a fungus would view as a 
food or nutrient; and (2) what is the effect of fungus growth on 
components would be when a nutrient material, such as Mt Dew, is spilled 
on it.   The first question relates to components as they come into our 
facility, the second is usually done on top level units as part of our 
functional qualification.

Doug Pauls



"Inge" <[log in to unmask]>
03/11/2010 09:34 AM
Please respond to
"Inge" <[log in to unmask]>


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Subject
Re: [TN] fungus question






Paulus Douglus,

I  see it in two ways.  Generally spoken, you are right. Not many fun guys 


become fungus today. However, another aspect is  this one: equipments are 
exposed to all sorts of environments, especially MILs, and all that spoky 
stuff that covers the electronic components can be broken down into all 
kind 
of unhealthy compounds, which can attack the 'plastics'.  So, the basic 
meaning with the tests is probably to see that the component in itself 
does 
not generate fungus, but there should be a second aspect, which points at 
what I said above.  Then comes the question: what do we mean with fungus. 
If we can harvest golden sepps for the evening meal, there is no doubt, 
but 
what about countless and nameless micro things. I have myself seen both 
metals and plastics covered by thin veils, which revealed millions of 
spectacular micro sized things that we could not name.  Looked like 
mycellum 
or mykorrhiza. That the 'things' were micron sized does not necessarily 
mean 
that they are harmless.

When I inspect units from different parts of the world, I can meet 
spiders, 
geckos, strange beatles and also strange coverings, sorts of. We don't do 
fungus testing, noone will pay for it, think that's the situation for the 
majority.

Why do you ask?  Maybe because of  a fan guy?

Inge



--------------------------------------------------
From: "Douglas Pauls" <[log in to unmask]>
Sent: den 10 March 2010 06:51
To: <[log in to unmask]>
Subject: [TN] fungus question

> Good morning all,
>
> Do any of you know whether electronic components are still tested for
> fungus resistance?  Since most components are molded plastic made from
> synthetic or petroleum-based materials, and therefore non-nutrient, I
> suspect that this kind of testing is no longer done, unless required to 
by
> a customer.
>
> Thanks.
>
> Doug Pauls
> Rockwell Collins
>
> Diet Dew
> Diet Dew
> Diet Dew
> (gotta get the hits back up)
>
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