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PCB X-ray Inspection

X-ray Inspection

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What is X-ray Inspection in PCB?

X-ray Visualization PCB

The automated X-ray inspection system is a non-destructive testing method used to inspect the internal structure of circuit assemblies. It is used to find the hidden defects of the targeted sample.

It is mainly used to identify the issues related to ICs and BGAs in PCB. For the scanning process, it uses X-ray as a source. The working principle of AXI is similar to that of Automatic Optical Inspection (AOI). The only difference is that AXI uses the X-ray for scanning while AOI uses the light source. 

PCB X-ray inspection is used in many applications, including medical PCBs, aerospace manufacturing, the telecommunication industry, and consumer electronics.

How X-ray Inspection Machines Work?

How X-ray Works?

PCB X-ray inspection works with the use of X-ray radiation that examines the PCB’s internal structure to identify any kinds of defects in the circuit board. Let’s look into how the AXI inspection works in detail:

X-ray Tube/Generator

It generated the X-ray radiation. The generated radios are directed towards the circuit board, which requires inspection. X-rays can penetrate various layers of PCB, creating the machine to reveal the details within the objects.

X-ray tubes are mainly of two types: one and closed tube. The type is selected based on the correspondence to the resolution of the inspected circuit board. With the increase in resolution, all the delicate details will be visible. 

For example, for BGAs, a resolution of 2 micrometers will be used. 

Sample Operation

This platform moves the sample to be inspected from various angles with various magnifications. This platform also helps examine the circuit board or the sample from an oblique angle. 

Detection System

There is a detection system on the opposite side of the circuit board. It captures the X-rays that pass through it. The system consists of a detector-like image sensor that converts the X-rays into visible light.

Image Processing

The visible signal light, as generated by the detector, is processed with the help of specialized software. The software will then examine and analyze the intensity and distribution of the X-rays. It will create an image of the internal structure of the circuit board, providing a visual representation that can be understood by the users. 

Inspection and Analysis

The generated image is then displayed on the screen. It allows the operators to inspect the quality of solder joints, detect cracks or voids, and also helps to verify the integration of the connection and components on the PCB

Quality Control

PCB X-ray inspection machines are used in quality control processes during manufacturing. It ensures the electronic components are assigned correctly and there are no defects in the final product

Types of X-Ray Inspection

2D X-ray Inspection

2D X-ray inspection system

2D X-ray inspection provides the 2D image of the object. It’s like taking a flat picture of the internal structure of a circuit board. This method is used for the inspection of the PCBs, electronics components, and other objects from the top-down view. 


The advantage of 2D X-ray inspection is it’s quick and cost-effective to identify the important details like solder joints and the placement of components. 


It has limited depth perception. It is impossible to see the sample from multiple angles, especially those hidden behind the other components. 

3D X-ray Inspection

3D X-ray Inspection System

3D X-ray inspection provides a 3D view of the object’s internal structure. You can have a 360-degree view of the circuit board. It could detect


It offers a more detailed and accurate view of the object’s internal structure and defects compared to a 2D X-ray inspection system. Thus, it provided detailed volumetric data of the circuit board. 


It is slower and requires more computational capacity, which makes it expensive compared to 2D systems.

Limitation of Using X-ray Inspection Method

Although X-ray inspection is a valuable tool for non-destructive testing and inspection, it does have some limitations:

  • It can’t detect particular contaminations (non-metallic) like wood, plastics, etc. 
  • Radiation of X-ray inspection can affect the shelf life of components.
  • The initial investment of an X-ray inspection system is more. 
  • It requires expertise and an experienced person to identify the defects.
  • The resolution of X-ray imaging is limited by various factors, like the size of the X-ray source and the detectors. 



Automated X-ray Inspection (AXI)

Automated Optical Inspection (AOI)

Inspection Method

Utilizes X-ray radiation to inspect internal features of PCBs

Uses visible light and cameras to inspect surface features of PCBs

Defect Detection Capability

Effective for detecting internal defects such as solder voids, insufficient solder, and component misalignment

Effective for detecting surface defects such as scratches, solder bridges, and component polarity

Inspection Speed

Typically slower due to the complexity of the X-ray imaging process

Generally faster as it relies on optical cameras for imaging

Material Transparency

Can inspect both opaque and transparent materials

Limited to inspecting components with visible surfaces

Cost of Equipment 

Expensive due to the complexity of X-ray machines

Typically less expensive as it involves optical cameras and lighting systems

Regulatory Compliance and Safety Considerations

When dealing with AXI, it’s important to consider several regulatory compliance and safety factors:

  1. Radiation Safety Regulations: AXI machines emit X-ray radiation, which can be harmful to people. It’s vital to follow radiation safety rules. This means putting safety measures in place to protect operators and ensuring the equipment meets safety standards.
  2. Environmental Regulations: Some places have rules about using and getting rid of equipment that gives off X-rays, like AXI machines. Adhering to these regulations ensures the safe use and proper disposal of AXI equipment to protect the environment.
  3. Quality Management Systems: In industries where AXI is used for quality control, meeting quality management standards like ISO 9001 or AS9100 might be necessary. These standards ensure inspection processes are well-documented, consistently applied, and improved to meet regulations and customer needs.
  4. Product Safety Standards: Depending on the industry, products checked with AXI may need to meet certain safety standards for consumers’ safety. AXI helps spot defects that could make products unsafe, helping meet these standards.
  5. Data Security and Privacy: AXI systems gather and keep sensitive inspection data, like pictures of electronic parts. Keeping this data safe is crucial, especially in industries where secrecy and protecting ideas are big deals. Following data protection laws, like GDPR in the EU, helps keep this information secure.

Future Trends and Innovations on AXI Inspection

  • The X-ray detector technology and the imaging algorithm help the AXI system feature higher resolution and faster inspection speeds. In the future, it will definitely help enable more efficient inspection technologies for complex electronic systems.
  • Integrating AI and ML algorithms in AXI will enhance the defect detection capabilities. It learns from a large number of datasets, which can help improve inspection accuracy and efficiency. Thus, it will help to reduce the false positives in the defect detection on the circuit board. 
  • AXI system can be integrated into the automated production lines for the in-line inspection. Thai trends solve the problem of real-time quality control and the need for production downtime. Integration of the robotic system enables the inspection of electron assemblies accurately and quickly. 
  • AXI systems will feature advanced data analytics capabilities for deeper insights into manufacturing processes and product quality. Integration with manufacturing execution systems (MES) and cloud-based platforms will enable real-time monitoring, analysis, and optimization of inspection processes.

ElePCB for X-ray Inspection Services

AXI Inspection

PCB inspection is one of the major crucial steps of any PCB manufacturing. Although inspection could be expensive, it is vital to carry out this step in order to ensure the devices are functioning properly. 

Thus, it is important to partner with PCB manufacturers, which should provide a quality system through PCB X-ray inspections. 

At ElePCB, we understand the importance of PCB quality control. Thus, we provide the full service from PCB design to assembly through a quality X-ray inspection system. We follow all the PCB guidelines and requirements for PCB assemblies. We ensure that we provide a quality PCB that aligns with industry standards. 

Learn more and request for a quote today. 


X-ray inspection machine offers benefits in terms of quality control, product safety, versatility, and efficiency. The machine helps the manufacturer to detect defects and ensures customer safety. 

While the AXI provides various benefits, it is important to consider regulatory compliance and safety considerations, including radiation and environmental regulations. You need to ensure it operates in a safe environmental condition with proper disposal of AXI equipment. 

Partnering with reliable PCB manufacturers that utilize quality X-ray inspection systems, such as ElePCB, ensures it follows industry standards and delivers high-quality PCB assemblies that meet customer requirements and specifications.


ELE PCB has got the IS09001:2015, IS013485:2016, ROHS and FCC certifications. We can offer all kinds of services, including PCB manufacturing and PCB assembly, sample orders and batch orders. For PCB assembly, utilizing 7 high-speed SMT PCBA lines from Yamaha and Sony, to meet our customers’ needs. Our extended services include PCB design &PCB Layout, hardware design engineering, firmware &software development, and personalization. ELE company is honored as an excellent supplier from any company all around the world. We deeply believe that our good service and experience will completely meet your needs. Integrality, value and innovation are the forces that drive our success.



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About the Author
I am an Electrical and Electronics Engineer, and I have 5 years of work experience with electronics and communication jobs. I'm the full time content creator of ELE company.
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