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Averna tapped its DFM experience to ensure that the product designs were optimized for the testing stages, and that most test processes could be automated to streamline throughput and prevent operator mistakes.

Communication on the battlefield is a life-or-death matter. You can't take chances with RF devices or power units malfunctioning or failing. A soldier's life may depend on how well you designed and tested your product. Will it function in temperature extremes, after physical shocks, and with low battery power? Where will it break or fail, and why? How can that be prevented?

A large military equipment supplier contacted Averna (Montreal, QE, Canada) to design a ground-up approach to top-level assembly (TLA) and circuit-card assembly (CCA) testing — from pre-functional and functional through environmental, electromagnetic, and repair — to ensure their mission-critical devices would test to specifications and not fail in the field. Averna's client designs and delivers military electronics products for use in aircraft, tanks, personnel carriers, and ships.

As well as being tasked with testing thousands of Communications Control Units (CCUs) and Power Distribution Units (PDUs), Averna also had to ensure that the entire test environment could be easily adapted for other products once the CCU and PDU testing was finished. The CCU is a modular Ethernet LAN device that hosts all required voice and data services needed in military vehicles; the PDU is designed to distribute up to 50 amps of 28-volt DC power to six output receptacles.

The complete Averna test system would need to provide full coverage to ensure the devices met specifications, increase automation and reduce operator interventions, catch defects as early as possible in manufacturing, and provide failure analysis, repair, and troubleshooting capabilities.

Averna was tasked with defining and deploying a complete manufacturing test solution for the CCUs and PDUs that would be installed in military vehicles. Averna's test system would be applied to the entire lifecycle, from product design through high-volume production, and a repair stage for any failed or damaged units.

To build this comprehensive test system, Averna applied Design for Test, Design for Manufacturing, teststation manufacturing, swappable fixtures, and project management. The Averna team included a program manager, system architects, engineers (test, electrical, and mechanical), and software developers who combined to develop the necessary infrastructure and equipment to fully test the two products at multiple stages.

Averna analyzed test coverage to ensure that both the CCU and PDU would be thoroughly tested, and that as many defects as possible could be eliminated before the manufacturing process began. The manufacturing test flow was defined in three stages - Top Level Assembly (TLA), Circuit Card Assemblies (CCAs), and Environmental Stress Screening (ESS). Individual CCAs would undergo pre-functional and functional testing before being assembled.

Over the course of the project, Averna provided consulting and analysis expertise, system and network architecture, and flexible ATEs for tests such as functional, ICT, environmental, assembly, and repair. The test system deliverables included nine common test stations (five different types) with interchangeable fixtures, industry-standard modular instrumentation (PXI), batch and parallel testing to optimize instrument use and throughput, NI TestStand and Lab-VIEW-based architecture from National Instruments, and automated test execution to reduce operator tasks and human errors.

Test Types and Flow

For Design for Test (DFT), Averna first analyzed the test coverage to ensure that both the CCU and PDU would be thoroughly tested, and that as many defects as possible could be eliminated before the manufacturing process began. The company used Design for Manufacturing (DFM) experience to ensure that the product designs were optimized for the testing stages, and that most test processes could be automated to streamline throughput and prevent operator mistakes.

The manufacturing test flow was defined in three stages: TLA, CCA, and Environmental Stress Screening (ESS). This would ensure optimal test coverage and early defect detection; for example, individual CCAs would undergo pre-functional and functional testing before being assembled. NI TestStand and LabVIEW, as well as the Averna Test Execution Console, were implemented to automate the testing — both batch and parallel — and to optimize the use of the PXI instrumentation.

Automated Test Interfaces

The simple GUIs sped up testing while eliminating manual steps — important for helping the client achieve its product quality and throughput goals. Averna Test Execution Console sits above NI TestStand and is configured for batch and parallel testing to optimize instrument use and increase throughput. Barcode-scanning of Units Under Test (UUT) minimizes operator interactions.

The Assembly graphical user interface enables the tracking of all subcomponent assemblies, and prevents production errors such as testing of defective components, untested components, and already tested components.

The Repair GUI identifies defective components based on UUT failures. It also provides statistics on previous failures, a failure count, and troubleshooting based on schematics and a Layout viewer. To gather production results, Averna deployed its Proligent Analytics test-data management software on each station. The data is automatically gathered and consolidated in a central data warehouse where it is available through Web-based manufacturing reports, charts, and alerts for key performance indicators (KPIs), quick analysis, and drill-down troubleshooting.

Results

Averna architected, sourced, assembled, and built five different “flexible” or “common” test stations (nine stations in total). To ensure the client got the most value from them, each station has an industry-standard rack, modular instruments, mass interconnects, quick-access doors, swappable intelligent fixtures and/or harnesses (including self-test fixtures), and multiple safety features.

This article was contributed by Averna, Montreal, QE, Canada. For more information, Click Here .