After the software performs its virtual vibration or acceleration tests, different colors indicate potential weak spots on the circuit board. (Image courtesy of Mentor Graphics).
Before a circuit board is installed in an automobile or satellite, it is clamped into mechanical jaws. For hours, the machine subjects it to heat and harsh vibrations that shake components loose like poorly-tied shoe laces. Using the board’s carcass, engineers can go back and improve the design.
This highly accelerated life cycle testing is usually done in special laboratories, which companies rent out for thousands of dollars to figure out the breaking point of their devices. The HALT method has been around for decades, but it is far from perfect: Companies spend hours doing "shake-and-bake tests and the results can vary.
Mentor Graphics, one of the largest makers of EDA tools, recently released software that can subject virtual circuit boards to vibration and acceleration tests. An add-on to its Xpedition software suite, the tools puts the board through a lifetime of harsh treatment, pointing out weak points earlier in the design process.
“We wanted to bring the validation and verification directly next to where parts are introduced so that the find-and-fix process can start sooner,” said David Weins, a product marketing manager at Mentor Graphics, in a recent interview.
The company is betting that the software will get electrical engineers involved in reliability testing way before handing off the boards to specialists, who detect flaws using mechanical analysis software. In that way, Weins said, companies can shave money and time off testing, which usually ends with HALT.
“With a mechanical tool, the parts would be boxes and cylinders with no intelligence,” he said, referring to how processors and capacitors are virtually rendered. But the Design for Reliability or DfR software provides a more detailed view of how vibrations and acceleration affect boards.
That can be important for ensuring that a product’s reliability is airtight before it enters production. Product failures can be extremely costly: In 2010, Toyota recalled over 1.1 million cars because a crack had been shown to develop on parts used to protect circuits against excessive voltage.
In a demonstration, the software showed the probability that certain parts on a circuit board would fail. The program marked high-risk components in red and low-risk parts in shades of orange, yellow, and green. Users can zoom into the pins, where the vast majority of failures take place, and identify the pins that have to be battened down.
The Xpedition software comes with three-dimensional models of over 4.8 million parts, which layout designers can drag and drop onto circuit boards for simulation. The software can also simulate mechanical parts like screws and washers, as well the jig that would hold the board during physical tests. Users can import parts missing from the library.
These precise models detect parts on the threshold of failure that would be missed during physical testing, said Weins. The models also make for extremely accurate simulations. In internal tests, the new software predicted 93% of failures that occurred in physical tests. It did so in several hours, much faster than the days-long HALT method.
The DfR software is the latest sign of how electrical and mechanical engineers are working closer on adding a digital dimension to cars and factory equipment. With new tools, engineers can hand off boards with more insight into their reliability, cutting down on the back-and-forth inside large engineering teams, Weins said.
That theme stuck out in Siemen’s acquisition of Mentor Graphics late last year. The industrial conglomerate spent $4.5 billion to fold the Oregon-based firm into its digital factory division, which sells software to help engineers manage the life cycle of products ranging from electric vehicle batteries to wind turbines.
“We’re not trying to replace HALT or mechanical analysis,” Weins said. “What we’re driving for is first-time-right designs.”