Hi Rudolph,

See my responses within.

On Mon, 8 Sep 2008 04:22:58 +0000, Rudolph yu 
<[log in to unmask]> wrote:

>Hi Technet members:
> 
>I am reviewing the current ESD practices at a OEM /EMS company 
which I have just joined couple months ago, and would like to seek for 
your expertise.
> 
>1.  The company uses epoxy pouring material +coating for the ESD 
floor.  According to the ESD hand book TR20.20, this type of ESD 
floor "DOES NOT" require maintenance.  How true is this statement?  If 
a customer ever challenge me on this, can I just direct him to the ESD 
handbook? (of course the point to point, point to ground resistances  
has to be within the acceptable range)
> 

Do you have any documentation on the flooring? Does it have 
dissipative properties? Can you show your customer a spec sheet from 
the manufacturer that it doesn't require maintenance (other then 
periodic cleaning)? 

> 
>2.  We use plastic tray to move assemblies between workstations with 
the whole facility which is considered as EPA.  ( I am assuming the tray 
material is dissipative material)   Is there anything we need to be aware 
of?  What if my assumption is wrong and the material turns out to be 
insulative? What can we we address this then?
> 

Are the trays black plastic? I haven't seen any plastic other than black 
that has dissipative properties. Do you know from where they were 
pruchased and have any information on them?

>3.  We put the BOM, assemblies, drawing on the tray along with the 
assemblies within the EPA area(  and I dont think they are ESD paper).  
Is this acceptable practice as far as ESD concerns? Do we "have to" 
cover all the documents in dissipative sleeve? Even if we use the 
sleeve, the inspector will need to take the BOM and assembly drawing 
out during the actual inspection ( for the highlight and crossout), what 
can we do to prevent static from being generated? Will it be ok as long 
as the inspector is grounded by wrist strap and heel strap?
> 

Paper is not generally considered to be a static generator, but that 
depends on the humidity level in your facility. If its is typically dry 
(<20%RH) you might have a problem. If it is typically 30-50% RH, you 
are probably OK. General rule of thumb is to keep all non-dissipative 
materials separated from ESD sensitive components as much as 
possible. 

You can also use ionizers at ESD workstations to dissipate static 
charges on the papaerwork.

>4.  We are renting the ESD garment from an outside company. What 
kind of spec should they follow for the periodically inspection and 
laundry services when we return the garment to them? 
> 

Again I would defer to the garment manufacturer's guidelines. See if 
they have a copy of them.

>Thanks for the help.
> 
>Rudolph 
> 

Hope this helps.

Blair 

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