This reference defines the fixture-mechanical and process terms used in test fixture design. For general PCB-testing terminology — bed-of-nails, ICT, DUT, PCBA, test coverage, and the rest — see the Testing Glossary.
Acronyms#
| Acronym | Meaning | Description |
|---|---|---|
| DFM | Design for Manufacturing | Design practices that optimize a product for efficient manufacturing |
| DFT | Design for Test | Design practices that enable effective testing of the product |
| FCT | Functional Circuit Test | Testing that verifies a board functions as designed |
| MTM | Manufacturing Test Modules | Acroname modular test equipment |
| TPCB | Test Point Carrier Board | Custom PCB that routes test probes to connectors |
Test Fixture Components#
Cartridge#
A replaceable/modular set of plates customized for testing a specific Device Under Test. Cartridges enable testing multiple products with a single fixture base, or quick replacement when probes wear out.
See: Cartridges
Fixture Base#
The permanent frame structure that holds cartridges and provides the mechanical action for fixture closure. Development and production bases differ in maximum force, cycle life, and actuation method.
See: Fixture Bases
Probe#
A test probe or pogo-pin—a replaceable spring probe that makes electrical contact with test points on the DUT. Probes compress when the fixture closes, maintaining contact pressure throughout the test.
See: Selecting Probes
Receptacle#
A container that a test probe presses into, enabling easy probe replacement without soldering. Receptacles mount in the probe plate and provide the electrical connection to instrumentation.
See: Receptacles Guide
Test Point Carrier Board (TPCB)#
A custom PCB that interfaces probes/receptacles to instrumentation and connectors. TPCBs route signals from individual probe locations to organized connector pins.
See: TPCB Guide
Probe Plate#
The plate in which receptacles are mounted. The probe plate positions probes to align with test points on the DUT.
Pressure Plate#
The moving plate that applies downward force on the DUT. Pressure pins mount to the pressure plate to distribute force across the board.
See: Pressure Application
Guide Pin#
Spring-loaded or fixed pins that engage mounting holes on the DUT to ensure accurate, repeatable positioning.
See: DUT Locating
Feedthrough Plate#
A panel that provides mounting locations for connectors between external instrumentation and fixture internals.
See: Feedthrough Plates
Fixture Process Terms#
Contact Force#
The downward force applied to ensure reliable probe-to-test-point contact. Measured in Newtons (N). Development fixtures typically provide up to 200N; production fixtures up to 2000N.
Cycle#
One complete test sequence: fixture close, test execution, fixture open. Cycle count determines fixture and probe wear.
Probe Travel#
The distance a probe can compress while maintaining contact. Also called working stroke.
Need More Information?#
For terms not covered here or questions about specific applications, contact us.