Test Fixture Design & Development
Bed-of-nails, functional testers, and end-of-line stations — built by engineers who understand the board being tested.
What is test fixture development?
Test fixture development is the design of the equipment that verifies electronics in production: bed-of-nails fixtures for in-circuit test, functional stations that exercise the product as it will be used in the field, and the software that drives them. We build fixtures that catch real defects at line speed, with pass/fail criteria traceable to the design.
Test is designed, not bolted on
The best time to design production test is while the board is still in layout. Test points cost fractions of a cent then. After fabrication, the missing pad under a critical net costs either coverage or a fixture workaround that operators will curse for years.
That is why our fixture work starts with a design-for-test review rather than a mechanical drawing. What must be measured, what can be probed, what the firmware needs to expose: settle those first, and the fixture that follows is smaller, cheaper, and catches more.
Proven next to the line that uses it
A fixture that has never seen a bad board is an untested product itself. Before anything judges production, we gauge it: known-good boards must pass repeatably, seeded faults must fail loudly, and marginal measurements get their limits set from real distributions instead of hope.
That proving happens on the same floor that will run the fixture daily, and feedback from operators lands directly on the engineers who can act on it.
ICT vs. functional test vs. flying probe: how should your boards be tested?
Production test is a coverage-versus-cost decision. In-circuit test finds assembly defects component by component, functional test proves the product works, and flying probe trades speed for zero fixture cost. Most products end up with a deliberate mix rather than a single answer.
| In-circuit test (ICT) | Functional test (FCT) | Flying probe | |
|---|---|---|---|
| What it catches | Wrong, missing, reversed, or unsoldered components | Whether the assembled product performs to spec | The same defect class as ICT, probed point by point |
| Fixture cost | A bed-of-nails fixture per board design | A custom station; cost follows product complexity | None — it is programmed, not built |
| Test time per board | Seconds | Seconds to minutes, set by what must be exercised | Minutes, because probes move sequentially |
| Best for | Volume production of stable designs | Every product at some depth before it ships | Prototypes and volumes too low to justify a fixture |
| What the design must provide | Test points placed during layout | Accessible interfaces and a firmware test mode | Probe-able nets; the fewest layout demands |
Fixtures and test systems we build
How a fixture is developed
- 01
Coverage Definition
First question: what must this line catch? The answer splits testing between in-circuit and functional stages and sets the coverage bar everything else is built to.
- 02
DFT Review
Test points, probe spacing, connector access, and a firmware test mode are reviewed on the layout while it can still change. This step is nearly free; skipping it never is.
- 03
Fixture Engineering
The press, the pin map, and the interface electronics are designed against the real board geometry, with pin types chosen for the signals they will carry.
- 04
Test Software
Sequences, measurement limits, operator flow, and traceability. A good station makes the pass/fail decision unambiguous and logs the evidence.
- 05
Line Proving
The fixture is gauged against known-good and seeded-fault boards before it judges production, then handed off with documentation and spares.
What arrives at your line
Fixture capability at a glance
Test Fixture Development FAQs
A test fixture is the equipment that verifies a board or product in production. A bed-of-nails fixture presses spring pins against test points to check the assembly component by component; a functional test station exercises the finished product the way a user will. Both exist to catch defects at line speed, before anything ships.
During board layout. Test points, probe spacing, connector access, and a firmware test mode all cost nearly nothing if planned then, and are painful to add after boards are fabricated. We review layouts for testability as a standard step, including boards other teams designed.
Yes. From design files it is straightforward: we extract the test-point map and net list and engineer the fixture from those. Without files, reverse engineering fills the gap first. Either way the fixture is proven against known-good and known-bad boards before it judges production.
Pin count, instrumentation, and coverage depth drive it. A manual pogo-pin programming jig is inexpensive. A pneumatic ICT fixture with full analog measurement and barcode traceability is a bigger investment that repays itself in caught defects and faster throughput. We quote against your board and your target coverage.
Yes. Pogo pins wear, limits need tuning as real yield data accumulates, and design revisions ripple into the fixture. Delivery includes spares, documentation, and maintenance guidance, and we stay available for updates when the board or the line changes.
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