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