Performing HASS

HASS - Highly Accelerated Stress Screen

HASS testing (Highly Accelerates Stress Screening) is a proven screening method developed to find manufacturing and production process induced defects in electronics and electro-mechanical assemblies, before those products are released to market. HASS testing is a powerful testing tool for improving product reliability, reducing warranty costs and increasing customer satisfaction.

After a product has undergone HALT, HASS can be deployed in the production process. The goal of a HASS test is to induce failure modes that can be inherent or introduced in the production process. HASS has been proven to be effective in screening failures that may have gone undetected in the burn-In testing process. A product that passes normal production tests but fails in a HASS would have probably failed early after product release, and thus increasing warranty costs.

There are 2 parts to HASS:

  • HASS Development/Proof-of-screen (POS)
  • HASS Production Screen

Since HASS stresses are more aggressive than conventional screening tests, a POS procedure is used to establish the effectiveness in revealing production induced defects. A POS is vital for determining that the HASS stresses are capable of revealing production defects, but not so extreme as to remove significant life from the Unit Under Test (UUT). Instituting HASS to screen product is an essential tool for maintaining a high level of product robustness. Since it will significantly reduce the test time required for product screening it also delivers long term savings. Ongoing HASS screening assures that any weak components or manufacturing process degradations are quickly detected and corrected.

highly accelerated stress test

In this diagram ESS (Environmental Stress Screening) is referenced to show its ineffectiveness against product to be shipped.

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