||PCB production and design-for-test (DFT) engineers often work on the same project without direct communication. This results in overly expensive revisions to product late in the development process, when boards are failing functional tests. In an article titled “Putting ‘Design’ Back into Design for Test,” Mark Laing, product marketing manager, Valor Division, Mentor — A Siemens Business, argues that while design for manufacturing (DFM) has become a proactive part of production, DFT is still lagging behind.
Laing discusses many reasons why product designers should care about test, in order to eliminate costly revisions that occur late in the product development cycle. “When designing a PCB, components are typically chosen without looking at their failure rates. Test points do not get placed on all the required nets, and BGA devices with hidden joints are selected,” writes Laing. “In this situation, the opportunity for defects to escape manufacturing test is much higher. As a result, many more defects than necessary must be found and repaired at the more expensive functional test stage.”
Laing goes on to discuss process vs. product verification, improving test coverage, test considerations during design, and how to optimize PCB layout for test.
This article was originally published in the July 2018 issue of U.S. Tech. Click the link to read: “Putting ‘Design’ Back into Design for Test”