Reliability Measured in Billions- Accelerated Life test

Reliability Measured in Billions- Accelerated Life test

Accelerated life-test plays a major role in the development of laser shutter or optical shutter to ensure quality, reliability, and durability throughout the product’s lifetime.

The What – Accelerate life-test is the process of testing a laser or optical shutter under maximum operating conditions (mechanical stress, maximum temperatures, shock and vibrations, electrical controls, etc.) in an effort to define lifetime specifications and identify failures modes to optimize laser shutter design. The reliability bathtub curve shows the three stages of the accelerated life-test, which helps identify failure rates at each stage.


The Why – All three stages of the reliability bathtub curve build confidence for OEM customers. Stage 1, which identifies and eliminates early failures through design improvements, gives OEM customers confidence during the initial product introduction. In Stage 2, normal life, failures are reduced to negligible rates to eliminate any downtime in OEM instruments. Finally, in Stage 3, wear-out failures help identify material or design changes needed to exceed lifetime specifications by multiple factors.

Customer Expected lifetime = 5 years of operation or ~10 million cycles
NMLaser actual lifetime = 10 years of operation or ~ 50-1000 million Cycles

The How – NMLaser facility is fully equipped with life test laboratories capable of handling continuous life testing for billions of cycles. The accelerated life-test environment requires noise control, temperature control, continuous electrical operation, particle collection, and data storage for continuous monitoring.


The Results – Over the past decade, NMLaser has completed numerous accelerated life-testing projects that have provided definite specifications for the lifetime of all laser shutters and optical shutters sold.

NM Laser accelerated life test program resulted in unmatched reliability and performance beyond customer lifetime needs while lessons learned continuously improve the next generation of laser shutters and optical shutters.

Test Duration =  100 Hz for 12 months @ 50% duty Cycle

100Hz x 3600s/hr. x 24hr/day = 

8,640,000 Cycles/day
8,640,000 Cycles X 365 days =  3.15e9 cycles or 3 billion cycles


Stage 1: Early failures Stage 2: Normal Life Stage 3: Wear out
2 Units for sensor  0 Units failed 3 units for wear
Improved sensor design  No change Improved Material choice
Author: Mohammad Khaliki, Engineering
March 20, 2023