Changes Coming to IPC Assembly Standards
LAS VEGAS -- Work on the latest revision to the industry standard for soldered electrical and electronic assemblies has begun, with the task group focused on vertical solder fill for Class 2 product and BGA voiding, among other topics.
J-STD-001G has a planned release date of 2017, says IPC director of assembly and standards technology Teresa Rowe, the trade association's staff liaison to the task group. 
She said the committee is considering data that indicate components with high pin counts -- defined as 14 or more leads -- can survive conditions with less solder than low-pin-count devices.
The "G" revision would also add acceptance criteria for new classes of components, such as electrolytic capacitors with leads extending directly below the device, then formed at a 90-degree angle parallel to the circuit board. The question for the task group, Rowe said, is how to define such a lead configuration: "Is it a gullwing, or something else," she said. Speaking to CIRCUITS ASSEMBLY during the IPC Apex Expo trade show in March, Rowe (pictured at right) added that the target number for solder fill for such components under consideration by the task group is 50%.
The new revision will also seek to clarify the internal thermal plane exception, Rowe said. The J-STD-001F amendment 1, released in December, doesn't allow for an exception for internal thermal plane for less than 75% fill if the soldered part has fewer than 14 leads.
Other assembly and joining specifications under review include the Component Mounting Handbook (IPC-CM-770), the Wire Harness Certification program based on IPC-WHMA-A-620, and a revision to IPC-A-630, the enclosures standard.
The "E" revision of IPC-CM-770 was published in 2004, with little activity since then. Designed as a tutorial on assembly and joining, the handbook needs to be brought up-to-date with current assembly techniques. Rowe said IPC is trying to ascertain whether there is interest in continuing the work.
IPC and industry members are working to advance certification to IPC-WHMA-A-620.
IPC-A-630 will undergo a revision that will include expanded criteria and a change in title to include "box build."
Finally, the task groups in charge of J-STD-001 and the related IPC-A-610 are working with US Department of Defense representatives on addenda specific to high-reliability military end-product.
