What Is ESS Testing – and Why Does It Matter?

What is Environmental Stress Screening?

Environmental Stress Screening (ESS) is a testing process in which electronic products or assemblies are exposed to controlled environmental stresses to identify latent defects and manufacturing weaknesses.

The objective is not to test a product until it fails. Instead, ESS is used to expose weaknesses that may remain undetected during normal functional testing but could lead to failures later in the product's lifetime.

Depending on the product and application, ESS may include:

Temperature cycling

Repeated heating and cooling can reveal weaknesses related to components, solder joints, electrical connections and assembly processes.

Vibration

Controlled vibration can expose mechanical weaknesses, loose connections and other problems that may occur during transportation or operation.

What can ESS testing reveal?

A product may pass a standard functional test and still contain weaknesses that only become visible after environmental stress.

ESS can help identify problems such as:

• Intermittent electrical connections
• Assembly and manufacturing defects
• Weak solder joints and connections
• Component-related failures
• Mechanical weaknesses
• Failures triggered by temperature changes or vibration

Finding these problems during production is generally far preferable to discovering them after a product has been delivered or installed in the field.

For products used in demanding or hard-to-access environments, a field failure can involve considerably more than the cost of replacing a component. It can result in downtime, service work, warranty costs and disruption for the customer.

When does ESS make sense?

ESS is particularly relevant for electronic products expected to operate reliably over long periods or under demanding environmental conditions. This can include subsea equipment, industrial systems and other electronics where field failures are costly or difficult to resolve.

ESS should therefore be considered as part of the overall production test strategy. Considering the requirements early in product development and industrialization can make it easier to build an effective and repeatable screening process into production.

More than an environmental chamber

An ESS solution can involve considerably more than placing a product in an environmental chamber.

During screening, the product may need to be powered, controlled, measured and functionally tested. The test system must detect whether environmental stress triggers an intermittent or permanent failure and provide the necessary test results.

Depending on the application, an ESS test system may include:

• Test strategy and system architecture
• Test fixtures and mechanical interfaces
• Instrumentation and measurement
• Automation and control
• Functional testing during screening
• Test data collection
• System upgrades and lifecycle support

The environmental equipment creates the stress conditions. The test system makes it possible to detect, measure and document how the product behaves under those conditions.

ESS test systems from Virinco

Virinco develops production test systems for electronic products and has delivered ESS solutions for several customers and applications, including subsea equipment and test solutions for Kongsberg Defence & Aerospace. Each system is developed around the requirements of the individual product and its production environment.

Because we work across product development, industrialization, test fixtures and production testing, we can consider ESS as part of the complete production process rather than as an isolated test station.

We can develop complete new ESS test systems or help customers upgrade and improve existing systems, for example when introducing new products, increasing test coverage or replacing obsolete equipment.

The objective is a practical and reliable test solution that identifies relevant weaknesses before products leave production.

Need an ESS or production test solution?

Whether you are planning a new ESS system, upgrading existing test equipment or reviewing your production test strategy, Virinco can help define and develop a solution for your product and production environment.