When is flying probe better than ICT?

When volumes are low and fixtures would cost more than the boards. A bed-of-nails fixture takes weeks and money; flying probe needs only the CAD data and can test prototypes and small batches economically, though it is slower per board.

Does functional test replace in-circuit test?

No. ICT finds component and interconnect faults quickly; functional test proves the assembly behaves as a product. A board can pass ICT and fail FCT, and the reverse happens when a fault is outside the ICT netlist.

Blog

PCB Test Methods Compared

Each method sees a different failure. A test plan is a coverage decision, not a checklist of machines.

Hitech Circuits Engineering Desk

Shenzhen, China · PCB fabrication and assembly

2 min read

Published: 2016-11-23

Last updated: 2026-10-18

Technical review: Process figures checked against our published capability sheet. View capability sheet

Professional China PCB Manufacturer Teach you How To Test PCBs

Visual and X-ray

SPI checks paste; AOI checks placement and fillets; X-ray checks hidden joints. They catch process faults before power is applied.

In-circuit and flying probe

ICT measures components and nets through a fixture; flying probe visits pads with moving heads. Both find opens, shorts and wrong values.

Functional and burn-in

Functional test runs the board as a product against a specification; burn-in stresses it thermally for a period. These catch design margin and early-life failures.

Building the plan

Start from the failure modes that matter: fine-pitch BGA (X-ray), high-value assemblies (ICT), safety functions (FCT), long-life products (burn-in). Then match the sample rate to the volume.

Technical Specifications

Inspection: SPI · AOI · X-ray · microscope
Electrical: ICT · flying probe · functional test · burn-in
Acceptance: IPC-A-610 workmanship

Frequently Asked Questions

When is flying probe better than ICT?
When volumes are low and fixtures would cost more than the boards. A bed-of-nails fixture takes weeks and money; flying probe needs only the CAD data and can test prototypes and small batches economically, though it is slower per board.
Does functional test replace in-circuit test?
No. ICT finds component and interconnect faults quickly; functional test proves the assembly behaves as a product. A board can pass ICT and fail FCT, and the reverse happens when a fault is outside the ICT netlist.

← Blog

Related engineering notes

Request a customer quote

Free engineering review and quote for PCB manufacturing, PCB assembly, component sourcing and box build.

Request a Quote Explore Capabilities