Reliability Testing

Scope

Reliability testing covers the evaluation of product and component dependability over time through the controlled application of stress, including accelerated, life-cycle, and stress-screening approaches. The specific program is built around the product, its expected use environment, and the reliability question being answered.

Key approaches within the scope include:

• Accelerated life testing (ALT) – applying elevated stress (temperature, voltage, load, humidity) to accelerate failure mechanisms and estimate life and failure rates under normal conditions
• HALT (Highly Accelerated Life Testing) – stepping temperature, vibration, and combined stresses beyond specification limits during development to rapidly expose design and process weaknesses and find operating/destruct margins
• HASS (Highly Accelerated Stress Screening) – applying accelerated stress as a production screen to precipitate and detect latent manufacturing defects before products ship
• Durability / life-cycle testing – repeatedly exercising a product (cycles of operation, actuation, or mechanical motion) to characterize wear-out and service life
• Environmental reliability stresses – temperature cycling, thermal shock, humidity, vibration, mechanical shock, and power cycling, applied singly or combined
• Reliability metrics – failure rate, mean time between failures (MTBF) / mean time to failure (MTTF), life distribution, and margins, depending on the program

Applications

• Electronics and components – exposing design and process weaknesses in circuit boards, modules, and components, and estimating field reliability
• Automotive – reliability and durability qualification of automotive electronics and components against the demanding vehicle environment and long service-life requirements
• Aerospace and defense – reliability testing of equipment that must perform dependably in harsh operational environments
• Medical devices – demonstrating that devices remain safe and functional over their service life and use cycles
• Consumer products – life-cycle and durability testing of products and mechanisms (hinges, switches, actuators) to confirm they survive expected use
• New product development – using HALT early to find and fix weaknesses before design freeze, reducing later field failures
• Production screening – HASS screening of production units to catch latent defects that would otherwise cause early-life field failures

Benefits

• Finds design weaknesses before they reach the field – HALT and accelerated testing expose the weak points of a design during development, when fixes are far cheaper than after launch
• Estimates product life and failure rates – accelerated life testing provides the data to predict how long products will last and how often they will fail, supporting warranty and reliability commitments
• Compresses time – accelerating stresses turns years of field exposure into a feasible test duration, so reliability is known before products spend years in service
• Reduces warranty cost and field failures – catching weaknesses and latent defects before shipment directly reduces returns, warranty claims, and reputational damage
• Screens out early-life defects – HASS catches the manufacturing defects responsible for early failures, improving the reliability of shipped product
• Supports reliability qualification – the data demonstrates that a product meets its reliability requirements for qualification and customer acceptance