I fully agree with Jon's response to your questions.  In 
addition, the situation you described for Class 2 equipment is 
nonconforming since you do not have 75% solder fill per Table 
4-1.

I don't know from your message why 75% solder fill cannot be 
determined.  If it's due to not being able to see the joint then 
an assumption of fill based on other PTH's in the area may be 
applicable.  If there is no visual obstruction, determination of 
% fill should not be a problem with normal inspection techniques 
such as the unaided eye, ring lamp or microscope.  If this is an 
extremely important characteristic to your company or your 
customer, then a microsection of the solder joints in question 
can be done.  My suggestion here would be to conduct an 
experiment on a sample group of boards populated with coated 
components with a meniscus and microsection them to determine 
solder fill on a statistically valid sample.

If wetting can't be determined on the secondary side there's a 
problem.  Wetting to the lead on the primary side, in most cases, 
cannot be determined since the lead is usually not visible.  
Wetting to the PTH barrel is usually visible unless something is 
obstructing your line of sight.

You are correct in that there is no minimum clearance specified 
between the solder fillet and the component meniscus for Class 1 
and 2 since the meniscus is allowed into the solder as long as 
the other conditions are met, ie., no risk of thermal damage, 
component mass is less than 10 grams and good wetting exists on 
the secondary side with no meniscus visible from the secondary 
side.

For Class 3 equipment however, the minimum clearance is specified 
as "visible clearance."  This means that the lead can be seen 
between the meniscus and the solder fillet.  It is not intended 
to be measured.

I hope this response has been helpful to you.  If you have further questions 
feel free to give me a call.

Bruce Wooldridge
DSC Communications Inc.
Vice Chairman, IPC-A-610 Task Group
214/519-6170
Internet:  [log in to unmask]
______________________________ Reply Separator _________________________________
Subject: Re: capacitor soldering
Author:  [log in to unmask] at SMTPLINK
Date:    05/10/95 03:33 PM


Gloria,

Page vi in the 610B explains that the solder side is the secondary side. 
The two terms slipped through our editing, the paragraph should have been 
reworded to only need to identify the side once. Using the two terms 
should not make a difference.

If you are getting a 75% fill on the rest of your leads I would assume 
that you are getting a good fill on the capacitors as well. 

This was one of the changes made in the 610B since no one could give us 
data showing that meniscus in the hole comprimised the performance or 
quality of the assembly.

**************************************************** 
Jon Holmen
Technical Project Manager
IPC
7380 N. Lincoln Ave
Lincolnwood IL  60646
Phone (708) 677-2850
Fax   (708) 677-9570
e-mail  [log in to unmask]
*****************************************************


On Wed, 10 May 1995 [log in to unmask] wrote:

>      
>      We have a discussion going on with the IPC 610 B figure 4-23 
>      and 4-24 which are on page 57. It seems we cannot come up with 
>      a majority rule on the insertion and soldering techniques of
>      the coated capacitor.
>       
>      The statement which we are concerned with:   Exhibits all around 
>      good wetting on secondary side and lead coating meniscus is not 
>      visible within connection on solder side.  We cannot understand why 
>      solder side is also called secondary side in the same sentence.
>      (Per the view 4-2 these mean the same.) 
>      
>      Our situation is, we have some meniscus into the solder on the top 
>      side or primary side with little or no wetting. We cannot ensure that 
>      the vertical fill of solder is 75% per table 4-1 Class 2.   
>      Also, there does not appear to be a minimum amount of lead space 
>      between the solder connection and the meniscus in 610 B.
>      This application has been changed from 610 A TO 610 B. 
>      
>      Thanks for any clarification we can get on this... 
> 
>