Technical resource
PCB assembly inspection and testing guide
SPI, AOI, X-ray, ICT and FCT are complementary methods. Choose them from the likely failure modes, available access and the evidence the product needs.
Practical checklist
Agree the inputs, responsibilities and acceptance
| Topic | Prepare or define | Check before release |
|---|---|---|
| SPI | Checks solder-paste deposition before placement | Does not establish finished solder-joint or electrical performance |
| AOI | Checks visible placement and assembly features | Cannot directly see all hidden terminations |
| X-ray | Examines hidden joints and internal solder features | Does not establish electrical or firmware functionality |
| ICT | Checks accessible circuit nodes and component behavior | Coverage depends on access, fixture and test program |
| FCT | Checks defined operating behavior under controlled conditions | Only demonstrates the functions and conditions actually tested |
| First article | Confirms the initial build against released requirements | Requires a defined checklist and approval decision |
Worked example
Turn the checklist into an engineering decision
Example: a motor controller can pass static checks yet fail during a load step. Define the load waveform, measurement points, communication behavior and acceptance limits in the FCT plan.
Action log
Close the gaps before production
- List the missing file or unresolved decision
- Assign a customer or supplier owner
- Record the proposed action and approval needed
- Identify the affected revision and target build
- Carry open items into the pilot release decision
Sources and use
A practical guide for project preparation
Editorial guidance from Keep Best EMS, organized around the manufacturing and engineering workflow described in the company profile. The worked example is illustrative, not a customer performance claim. Updated 28 September 2026.
Use this checklist with your product drawings, component data and agreed acceptance requirements. The final manufacturing and test plan is specific to the released product.
Engineering requirements
Separate production checks from product qualification
Production screening checks units against a released procedure. Functional verification demonstrates only the functions and operating conditions actually exercised. Reliability qualification requires its own samples, stress conditions, duration and acceptance criteria; passing FCT or an aging sequence alone does not establish service life, safety approval or full system reliability.
Define test coverage, stimulus and load conditions, measurement points, limits, software and fixture revisions, and required records. Specify measurement-equipment suitability and calibration requirements. Preserve failed results, approved repair actions and re-test history so a later pass does not erase the original finding.
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