Sigma Range
HALT & HASS

Highly Accelerated Life Testing & Highly Accelerates Stress Screening

Temperature Chambers & Multi Axis Random Vibration Systems from Two Industry Leaders

The test combines two elements. Firstly rapid temperature cycling of the test item is introduced to cause different rates of expansion and contraction in the various components of the test item thereby imparting stress and inducing premature failures.

Secondly to achieve meaningful results high energy, broad band random vibration with six degrees of freedom is input through a modally rich table either during temperature ramps or more commonly during dwells.

HASS (highly accelerated stress test) is used as part of the production process and quickly detects component and manufacturing irregularities. Rapid temperature cycling and multi axis random vibration are used in the same way, but once the product parameters are known from the HALT process, testing in production is usually at lower levels so that useful product life is not reduced.

Competitors (RS type) tables, shown in blue, are of solid construction and therefore display vibration energy characteristics up to as high as 10,000Hz but show little energy below 1,000Hz where the most useful frequencies for environmental stress testing are found. Vibration screening effect depends on displacement not frequency.

Screening Systems (QRS type) vibration tables, shown in red, are patented and designed to eliminate useless and potentially harmful energy above 5,000Hz and show higher energy levels at lower frequencies than competitors RS type tables.

QRS tables have been proven many times to find more defects, more quickly than other types of vibration table. The QRS table design also minimises thermal transfer from the chamber to the pneumatic actuators.

Uniformity of vibration energy across the table in all three linear axes is also important, especially when multiple components are being tested at the same time.

Due to the modally damped design of the QRS table uniformity is much improved above other types of table shown on the right.