I hope you all can help us with a question I have received from one of our
manufacturing lines. We have a component (a surface mount crystal), which is
on page 40 of the link below. Can you tell us what kind of lead would this
be considered? Is it a flat lead, round lead, etc.

We had an issue with the solder under the lead not completely flowing out to
the end of the toe of the lead. We realize there does not need to be a toe
fillet. However, when we went to look in the IPC-A-610 to see what the
criteria would be for this type of lead, nothing really fits. The product we
are working with is a Class 3 product. There is sufficient solder paste on
this surface mount pad, but due to the design of the component (the leads
bow slightly up making the leads not completely flat on the pad.), the
solder stops halfway under the lead. There is not a heel fillet, since this
lead comes down out of the component and flat out.

Finally I get to the question: Should the solder flow completely out on the
pad and lead to the end of the pad and lead for a Class 3? We would
appreciate any information provided. Thanks.

Mary Jane Chism


http://www.pdixtal.com/pdf/PDICatalog1.pdf