Randy,

The solder coating thickness is located in Table 3-5 (page 13). For 
Class 2, the requirement is 2.5 micrometers (0.0001") minimum.

IPC-D-275 superseded IPC-D-949 upon its publication in September 1991. 
This is specified on the cover of IPC-D-275 (at least, it is on the cover 
of the copy I have).

IPC-D-275 does not list a solder coating thickness. Rather, it states 
that the requirement shall meet the solderability requirements of IPC-S-804 
(which was superseded by J-STD-003). Neither S-804 nor J-003 
stipulates a minimum thickness. Rather, they contain test
methods (edge dip, solder float, wetting balance, etc.) by which one can 
determine solderability (as opposed to measuring thickness; what a concept). 
Therefore, if you meet the requirements of D-275, you might meet the 
requirement (2.5 um) of IPC-D-949.

If a minimum thickness must be specified, I would use IPC-RB-276, 
amendment 1.

Mike Buetow
IPC Technical Staff
2215 Sanders Road
Northbrook, IL 60062
P: 847-509-9700, ext. 335
F: 847-509-9798
[log in to unmask]


On Thu, 2 May 1996 [log in to unmask] wrote:

> I have a customer specification requirement to inspect solder coating 
> thickness per IPC-D-949 Class 2.  I reviewed the Design Guide and did not 
> find any solder coat thickness requirements.
> 
> Where in this IPC spec is the solder coat thickness requirements?
> 
> What is the relationship of IPC-D-949 and IPC-D-275?
> 
> If I use the solder coat thickness in IPC-D-275, do I meet the 
> requirements of IPC-D-949?
> 
> Your help is appreciated.
> 
> Randy Reed
> Merix Corporation
> [log in to unmask]
> 
>