PCBA Testing Methods Explained: AOI, X-Ray, ICT, FCT

PCB assembly quality does not end after soldering. Testing and inspection are essential to ensure reliability, performance, and compliance with design requirements.

Dans ce guide, TOPFAST, a professional PCB manufacturer, explains the most common PCBA testing methods, their working principles, and when each method should be applied.

Why PCBA Testing Is Important

PCBA testing helps:

• Detect assembly defects early
• Reduce field failures
• Improve product reliability
• Lower warranty and repair costs

Testing is especially critical for automotive, medical, industrial, and telecom electronics.

Common PCBA Defects Detected by Testing

• Solder bridges
• Cold solder joints
• Missing or misplaced components
• Polarity errors
• Short circuits and open circuits

Proper testing ensures these issues are identified before shipment.

AOI (Inspection optique automatisée)

What Is AOI Testing?

AOI uses high-resolution cameras to inspect solder joints and component placement.

What AOI Detects:

• Component misalignment
• Missing components
• Solder bridging
• Insufficient or excessive solder

Advantages of AOI:

• Fast and automated
• Ideal for SMT assembly
• High repeatability

AOI is typically used after reflow soldering.

Related process:
Explication du processus d'assemblage des circuits imprimés

Inspection par rayons X

What Is X-Ray Inspection?

X-ray inspection allows inspection of hidden solder joints, especially for:

• BGA
• QFN
• LGA
• CSP packages

What X-Ray Detects:

• Voids in solder joints
• Head-in-pillow defects
• Hidden shorts or opens

X-ray inspection is essential for high-density SMT designs.

ICT (In-Circuit Testing)

What Is ICT?

In-Circuit Testing (ICT) checks individual components and electrical connections on a powered-off PCB.

ICT Can Detect:

• Shorts and opens
• Incorrect component values
• Orientation errors

ICT Limitations:

• Requires test points
• Higher setup cost

ICT is commonly used in medium to high-volume production.

FCT (Functional Circuit Testing)

What Is Functional Testing?

Functional Circuit Testing (FCT) verifies whether the assembled PCB functions as intended in real operating conditions.

FCT Includes:

• Power-on testing
• Signal and communication tests
• Software or firmware verification

FCT provides the highest level of confidence in product performance.

Inspection visuelle

Visual inspection is usually performed:

• Before and after soldering
• During final quality control

Although manual, it remains useful for detecting obvious defects.

Choosing the Right PCBA Testing Method

Testing Method	Meilleur pour
AOI	SMT solder quality
Rayons X	Hidden joints (BGA)
ICT	Electrical integrity
FCT	Overall functionality

Most projects utilize multiple testing methods to achieve optimal results.

PCBA Testing Cost Considerations

Testing cost depends on:

• PCB complexity
• Testing method used
• Volume of production
• Fixture and setup requirements

👉 Guide connexe :
Explication du coût d'assemblage des circuits imprimés

PCBA Testing in Turnkey PCB Assembly

In turnkey PCB assembly, testing is integrated into the production process.

Article connexe :
Qu'est-ce que l'assemblage clé en main de circuits imprimés et comment cela fonctionne-t-il ?

TOPFAST provides flexible testing options based on customer requirements.

Industries That Require Strict PCBA Testing

• Dispositifs médicaux
• Électronique automobile
• Aérospatiale
• Automatisation industrielle
• Télécommunications

In these industries, testing is not optional—it is mandatory.

Why TOPFAST PCBA Testing Services?

En tant que fabricant professionnel de circuits imprimés, TOPFAST offers:

• AOI and X-ray inspection
• ICT and functional testing
• Experienced QC engineers
• Documented test reports
• Reliable quality assurance

Our testing processes ensure consistent quality from prototype to mass production.

PCBA Testing FAQ