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Burn-in is the process by which components of a system are exercised before being placed in service (and often, before the system being completely assembled from those components). This testing process will force certain failures to occur under supervised conditions so an understanding of load capacity of the product can be established.
The intention is to detect those particular components that would fail as a result of the initial, high-failure rate portion of the
bathtub curve
The bathtub curve is widely used in reliability engineering and deterioration modeling. It describes a particular form of the hazard function which comprises three parts:
*The first part is a decreasing failure rate, known as early failures.
*Th ...
of component
reliability
Reliability, reliable, or unreliable may refer to:
Science, technology, and mathematics Computing
* Data reliability (disambiguation), a property of some disk arrays in computer storage
* High availability
* Reliability (computer networking), a ...
. If the burn-in period is made sufficiently long (and, perhaps, artificially stressful), the system can then be trusted to be mostly free of further early failures once the burn-in process is complete.
Theoretically, any weak components would fail during the "Burn In" time allowing those parts to be replaced. Replacing the weak components would prevent premature failure, infant mortality failure, or other latent defects.
When the equivalent lifetime of the stress is extended into the increasing part of the bathtub-like failure-rate curve, the effect of the burn-in is a reduction of
product lifetime
Product lifetime or product lifespan is the time interval from when a product is sold to when it is discarded.
Product lifetime is slightly different from service life because the latter consider only the effective time the product is used. It is ...
. In a mature production it is not easy to determine whether there is a decreasing failure rate. To determine the failure time distribution for a very low percentage of the production, one would have to destroy a very large number of devices. By stressing all devices for a certain burn-in time the devices with the highest failure rate fail first and can be taken out of the cohort. Thus by applying a burn-in, early in-use system failures can be avoided at the expense (tradeoff) of a reduced yield caused by the burn-in process.
When possible, it is better to eliminate the root cause of early failures than doing a burn-in. Because of this, a process that initially uses burn-in may eventually phase it out as the various root causes for failures are identified and eliminated.
For
electronic components, burn-in is frequently conducted at elevated
temperature
Temperature is a physical quantity that expresses quantitatively the perceptions of hotness and coldness. Temperature is measurement, measured with a thermometer.
Thermometers are calibrated in various Conversion of units of temperature, temp ...
and perhaps elevated
voltage
Voltage, also known as electric pressure, electric tension, or (electric) potential difference, is the difference in electric potential between two points. In a static electric field, it corresponds to the work needed per unit of charge to ...
. This process may also be called heat soaking. The components may be under continuous test or simply tested at the end of the burn-in period.
There is another use of the term by some
audiophile
An audiophile is a person who is enthusiastic about high-fidelity sound reproduction. An audiophile seeks to reproduce the sound of a piece of recorded music or a live musical performance, typically inside closed headphones, In-ear monitors, open ...
s, who leave new audio equipment turned on for multiple days or weeks, to get the components to achieve optimal performance. However, many debates have arisen about the benefits of this practice.
See also
*
Burn-in oven
*
Failure rate
*
Reliability theory
Reliability engineering is a sub-discipline of systems engineering that emphasizes the ability of equipment to function without failure. Reliability describes the ability of a system or component to function under stated conditions for a specifi ...
*
Survival analysis
Survival analysis is a branch of statistics for analyzing the expected duration of time until one event occurs, such as death in biological organisms and failure in mechanical systems. This topic is called reliability theory or reliability analysi ...
*
Dielectric withstand test A dielectric withstand test (or pressure test, high potential or hipot test) is an electrical test performed on a component or product to determine the effectiveness of its insulation. The test may be between mutually insulated sections of a part ...
*
Shakedown (testing)
A shakedown is a period of testing or a trial journey undergone by a ship, aircraft or other craft and its crew before being declared operational. Statistically, a proportion of the components will fail after a relatively short period of use, and ...
References
{{DEFAULTSORT:Burn-In
Environmental testing
Hardware testing