"David T. Novick" <[log in to unmask]> Wrote:
| 
|      On 5 June 1996 a request from manufacturing engineering 
| was placed for 
|      forwarding to TechNet.  This request is as follows:
|      
|      Several programs going into production will be using 
| plastic parts.  
|      There parts tend to absorb moisture and will crack 
| during the reflow 
|      process.  Since our entire experience has been with 
| military 
|      packaging, we are not certain what to expect from 
| plastic components.  
|      We are requesting information on the packaging and 
| storage of these 
|      parts.  We also would like to know the baking parameters 
| typically 
|      required to mitigate any risk during the soldering 
| processes utilized 
|      throughout industry.  It is our understanding that if 
| these parts are 
|      exposed to humidity for a period of time we need to 
| vacuum bake them.  
|      However we do not know for what period of time and at 
| what 
|      temperatures.  Since this is an area which is fairly new 
| to us, we 
|      need all the feedback we can get.
|      
|      Thanks for your help.
|      
|      Rosaura Corral-Perez
| 

The following is a  ASSY message.  


Rosaura:

You need to have dry storage cabinets (Stanely Vidmar is a good source)to 
store these parts once you open moisture barrier bag and keep track of the 
time that the parts spent on the shop floor.  For plastic encapsulated IC 
components, there are 6 moisture sensitivity levels and each of them have 
different floor life after bag is opened.

IPC-SM-786A gives general information on plastic parts.  JEDEC A-112A 
gives moisture sensitivity classification requirement.  EIA-583 gives 
packaging material requirement.  EIA/JEP 113-A gives symbols and label 
requirement, where you can find storage requirement and time requirement. 
 MIL-D-3464D gives desiccant requirement.  MIL-I-8835A gives humidity 
indicator card requriement.  JESD22-A113-A gives preconditioning flow 
requirement.

Hope you find the above info useful.  Good Luck.

Nora 

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