HALT + HASS Testing - Esterline Interface Technologies - #4

chamber or by tracking field failure issues and their frequency. Again, the best mode is to find failures before they reach the consumer.

6. Document experiences: The goal is to not only capture the experiences of the testing as it relates one project, but to take all learned experiences and apply them to future product designs before they ever reach the HALT / HASS process. This is where design experiences snowball into better and better products as a result of

testing feedback.

Advanced Input Systems uses a Thermotron AST chamber in our Coeur d'Alene facility for both the HALT & HASS testing to subject the parts to stresses—ensuring that a specific set of conditions will be replicated within a chambered environment to exact, repeatable condi­tions. Within this chamber products are submitted to the following conditions: rapid temperature fluctua­tions (extreme cold to high heat in a matter of seconds), sequential temperature step stresses, various voltage ranges, power cycling, vibration extremes or a combina­tion of any of the above at the same time.

The HALT / HASS process is used, as an example, to find some of the following flaws or problems:

• Mechanical defects /

design flaws

• Solder quality issues

• Broken component leads

• Shorts between components

• Broken traces or wires

• Screws backed out / broken

• Electrical defects /

design flaws

• Defective components

not meeting spec

• Hidden stress points in the design

• Marginal circuit designs

1. Precipitation: Changing a hidden, latent or undeveloped flaw into a developed and exposed flaw by the application of accelerated stresses in rapid temperature cycling, temperature extremes, voltage margining, vibration or a combination of all these items. This step is performed in the HALT / HASS chamber.

2. Detection: Once the flaw is developed after the HALT / HASS process, it is detected by means of visual, electrical or functional inspection. The flaw is documented and specifically stated for the next step involving evaluation.

3. Failure analysis: All causes and conditions are considered to the end that the reason for the failure is determined specifically. This becomes the root cause of the failure found in the testing chamber and is documented as such.

4. Corrective Action: As a result of determining the root cause—changes are made to either the production

process, the components or the mechanical design in

order to remove the flaw found during testing from

the design.

5. Verification: Follow up is necessary to verify that the root cause analysis and subsequent corrective action deemed necessary did in fact correct the problem found during the HALT / HASS process. This can be done through another round of testing within the

fAdvanced Input Systems

Advanced Input Systems 600 W. Wilbur Avenue Coeur d'Alene, ID 83815 USA

sales@advanced-input.com www.advanced-input.com