QualMark's patented OVS (OmniAxial Vibration System) tables used in their HALT and HASS chambers excite every part of a product, down to the component level, at its resonant frequency. This requires vibration in all three axes as well as the rotation around those axes, simultaneously, across a wide frequency range. At the same time, and within the same chamber, thermal tests are undertaken.  The chamber's patented Typhoon air-handling technology drives products from ambient to the appropriate stress temperature quickly using less electricity and liquid nitrogen.  
 
"If you looked at a pie-chart and it showed all possible defects, you'd have a certain percentage showing up at extreme high and low temperatures, during thermal cycling, under vibration in all axes, and during combined vibration and thermal cycling," said Charlie Bates, VP of program development.  "To cover all the bases you have to test both vibe' and temp simultaneously, because studies have shown that you can otherwise miss 25-30% of the defects."
 
In addition, thorough HALT and HASS testing requires broad frequency excitation, far beyond what a product might see in the end use environment, to ensure that weak links are quickly exposed.
 
"Our new xLF vibration system is unique in shifting the energy in the frequency domain down to the zero to 5,000 Hz range. With 50% of the energy below 2,000 Hz and 50% above, we simulate the resident frequencies in various types of electronic hardware, including PCBs," continued Bates. "This quickly brings out potential real-world problems such as weak solder joints and incomplete surface-mount connections."
 
QualMark authorized test centers have conducted over 4,000 HALT and HASS tests since
1991, employing services such as customer directed testing, production screening, production HASA (Highly Accelerated Stress Audits) and on-site testing.
 
QualMark, qualmark.com