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Production Testing

The results of testing in the Design Phase are used to improve the product design in order to achieve improved reliability and robustness. However, unreliability can still be caused by poor component quality, manufacturing defects (e.g. dry solder joints), or worst-case tolerance combinations, and these can vary from batch to batch. You therefore need an effective method of screening out these problem areas on a 100% basis to achieve the best possible product reliability. This is the function of Burn-In, Stress Screening and HASS.

 

Burn-In Test Methods

Burn-in testing is similar to Life Test (and often uses the same equipment), but is applied to all of the products rather than on a sample basis. Most failures occur early in the life of the product (infant mortalities), and can therefore be screened out by a relatively short Burn-in process.burn-in chamber

Burn-in is particularly effective at precipitating chemical contamination failures by using a combination of high temperature and voltage stress. It is therefore mainly used for electronic components.

Sharetree can offer a number of suitable Burn-in solutions, depending on the size and complexity of the products. These include Tray, Carrier and Trolley loading systems.

Stress Screening

Additional production processes introduce further potential failures due to unreliable solder joints, connectors, fixings and additional components, etc. The most effective method of detecting these weaknesses is through temperature cycling, which applies stress through the differential thermal expansion of dissimilar materials.

Thermal Stress screening is therefore used mainly at the sub-assembly and final assembly stages of production.

Sharetree offer temperature cycling chambers in a wide range of sizes and performance levels.

HASS - Highly Accelerated Stress Screening

The HASS process is similar to Stress Screening but uses much more aggressive stress levels in order to reduce the test time. The stress levels need to be carefully selected to ensure detection of product weaknesses while avoiding damage to good products. The stress parameters are usually based on the results from an initial HALT evaluation.

Sharetree offer Thermal Stress chambers specifically designed for HALT/HASS testing of sub-assemblies and complete products; these feature rapid temperature change rates, wide temperature ranges, and powerful air flow. Complete systems can also be supplied, with product fixturing, power supplies, and computer control and monitoring.