End of Line Test: Production Board Assembly Testers


Automate the process of testing printed circuit board assemblies to reduce test time, improve repeatability, and improve product reliability.


Bed-of-nails test fixture with National Instruments (NI) off-the-shelf hardware and LabVIEW-based scripting of individualized tests to verify pass/fail criteria and log results. 


In the early stages of development, circuit boards can be tested manually using an array of benchtop instrumentation. In some cases, it may even be desirable to test manually as it is easy to change the parameters of the test or test at different probe points to ensure the best design and product. 

When the circuit boards move into production quantities and test parameters are locked down, manual testing is a bottleneck to throughput. Test duration, repeatability, and integrity of the results are difficult to control. 

As a contract manufacturer, Tecnova Electronics assembles large quantities of circuit boards per year for client products. To reduce test time, increase throughput, and eliminate unnecessary operator intervention and error, the concept of a bed-of-nails tester is employed at the end of each assembly line. The “nails” are electrical probe points within the test fixture that contact various points on the circuit board. Off-the-shelf measurement hardware from NI is used within the test fixture to control and monitor circuit performance. 

A test executive software application written in NI LabVIEW allows the operator to scan a 1D or 2D product barcode prior to test. The barcode identifies the installed circuit board and the executive loads and runs the appropriate series of individual tests. Test results are compared to a database of pass/fail criteria, and results are logged to the database for future analysis and retrieval. On-demand report generation allows the operator to query the database and print reports in HTML format. A software plug-in architecture allows creation of alternate report formats. 

End-of-line testers eliminate as much user interaction as possible, reducing repetitive stress injuries and increasing test data reliability. Test times are greatly reduced, meaning more boards can be produced per day. Additionally, the use of test scripting and a database for test parameters and logging increases data integrity and decreases unauthorized changes to test methods and limits.

“End-of-line production testers are used throughout Tecnova Electronics every day. Without them, our ability to fulfill client needs with quality products would not be possible.”