Hi Philip -

In response:

1. Please let me know if you have any information regarding pre-tinning of the 
leads of metal can devices and guidance where solder gets into contact with 
component bodies.   In previous contracts for USA we were advised that solder 
contact on bodies meant reject.

**Many components can have the "pretinning" contact the component bodies but 
there are many instances (e.g. crystals) where it can not because it would 
damage the component. The standard rule of thumb is to avoid tinning right to 
the component bodies. You could make up a list of what parts can and can't have 
tinning touch the component bodies but this would be time consuming. 

2. J-STD-002 section 3.5.1 calls for a temperature of 260 +- 5 deg cent. in 
connection with the temperature of the solder pot.     The question from 
ourselves is the effect of the solder pot not keeping to the required tolerance 
spec.

**Most solder pots are capable of maintaining the +/- 5 C temperature. The 
temperature tolerance was put into the specification so that the test conditions
the test samples are subjected to are the same whether the test location is in 
Iowa or China. Test D is a measure of the dissolution rate of a component 
metallization and the temperature is an important variable. You should control 
the solder pot to the +/- 5 C for those two reasons.

3. Please let me know if IPC have produced a document to supersede MIl-C-28809 
which is now withdrawn.

**Sorry, I don't an answer to this one.

Good Luck.


Dave Hillman
Rockwell Collins
[log in to unmask]



______________________________ Reply Separator _________________________________
Subject: Technical queries previously submitted via internet
Author:  [log in to unmask] at ccmgw1
Date:    11/26/96 3:58 AM


Please excuse me if these following questions are already in your system.  We at
this end are experiencing computer problems.

1. Please let me know if you have any information regarding pre-tinning of the 
leads of metal can devices and guidance where solder gets into contact with 
component bodies.   In previous contracts for USA we were advised that solder 
contact on bodies meant reject.
     
2. J-STD-002 section 3.5.1 calls for a temperature of 260 +- 5 deg cent. in 
connection with the temperature of the solder pot.     The question from 
ourselves is the effect of the solder pot not keeping to the required tolerance 
spec.
     
3. Please let me know if IPC have produced a document to supersede MIl-C-28809 
which is now withdrawn.
     
     
Thanks 
     
     
Philip Duncan
Interconnection Engineering 
     
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