X-Ray PCB testing

X-Ray PCB testing:

X-ray examination technology, also called automatic x-ray examination, is a technology that can detect hidden features within a target object. From the medical industry to aerospace manufacturing, x-ray testing is the most widely used method of diagnosing production defects. It is widespread in PCB testing, as x-rays are an excellent way to check PCB quality and detect hidden errors without compromising the board. In this guide, we will discuss what x-ray testing is, how it works, and what the benefits are to understand how to use xB ray x-ray testing for your company's purposes.

Why X-Ray Machines Become Famous in Electrical Engineering?

Electronic manufacturing has become increasingly sophisticated in the last few decades, as electronic devices in the industrial, communications, military, and aviation industries evolve in ways that make testing more difficult.

Some of the most critical trends that negatively affect testing include:

  • Partition: Resources become smaller and have more layers to save space and increase efficiency. As a result, many solder joints and components are either transferred to internal components within electronics or placed between PCB layers, or hidden within the final product itself.
  • Partial size: Many regional board components are trending in miniaturization. PCB components are expected to continue this practice with the need to create dense boards.
  • SMT: Surface Mount technology makes track and packages smaller, which has resulted in PCBs having higher density and more material hidden between layers.

The increasing density, diminishing size, and complex layout of PCBs and their components have made it almost impossible for traditional testing methods to detect complete errors. Optical, ultrasonic, and thermal imaging methods do not work due to the congestion of modern PCBs.

However, x-ray examinations can collect detailed images where these alternatives may not be possible. An X-ray can penetrate PCB layers to examine internal layers and packaging, making it extremely useful for investigating solder joints for complex PCB assemblies. For this reason, PCB testing with x-ray technology is becoming increasingly popular.

How X-Ray Testing Works?

To understand what an x-ray PCB test is, you first need to know how an x-ray test works. All x-ray diagnostic devices are made up of three essential features:

  • X-ray tube: This tube is capable of producing x-ray photons.
  • Platform: The field of operation distributes the sample to different locations, allowing it to be tested at different angles and sizes.
  • Detector: A detector on the other side of the sample captures and collects x-ray photons, converting them into photographs.

X-ray imaging worked using x-ray photons transmitted by something and collected on the other side. X-ray photons transcend material used differently depending on their physical properties, including atomic weight, density, and density.

Usually, heavy elements absorb large quantities of x-rays, making them easier to photograph while more intricate details appear. Because different materials work differently, different amounts of photons are collected on the other side of the object, leading to the image. The components in the PCB usually consist of heavy elements, which makes them easier to see in an x-ray image.

X-Ray Machine Categories:

PCB x-ray scanning systems can be divided into two sets of categories. The designs can be 2D or 3D and can be used offline or offline. This is explained in more detail below:

  • 2D System: 2D x-ray system displays 2D images from both sides of the PCB simultaneously, creating an image of board components. This is similar to the traditional x-ray concept used to look at fractures. 2D Systems can be used online or offline.
  • 3D Systems: The 3D x-ray system can create 3D images by creating a series of opposite 2D sections. This is similar to how a CT scan works in the medical field. 3D x-ray is also performed using a laminography method, which combines different stages to form a specific part or area. The CT method can only be performed offline due to the complex algorithms used, while the laminography method can be used online.
  • Online Performance: Some x-ray devices are used online for data collection and comparison purposes. This makes it easier to process large amounts of complex PCBs. However, the power of the internet makes the x-ray machine slower, which increases costs while reducing capacity.
  • Offline operation: All x-ray devices can be used offline to complete panel and sample testing. Offline tools are usually faster but less expensive as they have a higher product value.

Choosing the best operating system should be done carefully - choosing a 2D or 3D design with the internet or offline capabilities will depend on the amount of product testing, the quality of the test you want, and the time available to complete the testing process.

Benefits of Quality Control and Evaluation:

In x-ray images of PCBs, the metal is black while other materials such as glass, plastic, and metal are exposed. This makes it easier to see the metal parts. Combined with magnifying power, this allows testers to see the various metal parts on the board during PCB testing with x-ray machines. The x-ray will enable the examiners to identify many of the characteristics of the printed circuit and identify a list of possible problems, including:

  • Solder Bridges: Commercial bridges are a common problem on regional boards. This happens when the solder joints are too close or connect where they should not be. These solder problems are often concealed in other parts, making them difficult to detect by visual inspection, but x-rays can quickly identify them.
  • Solder voids: Solder voids are formed when gas or flux is caught in a leak, usually due to water contamination of the solder paste. These voids reduce the heat dissipation in the solder area and can cause physical degradation and reduced reliability. X-ray is one of the only ways to identify solder voids, so it is essential to use it regularly to ensure product quality and processing quality.
  • PIN hole filling: Insufficient PIN hole filling for the outlet hole connectors is common for circuit boards. X-ray machines can be used to identify these defects and even to calculate missing inclusions using correlation measurements.


One direct example of how x-ray is used is the ball grid (BGA) test. BGA is a high-performance tool that uses a series of solder-sized metal spheres to make connections. This device is popular as it allows for very high connectivity without making it difficult for PCB structures.

However, the difficulty with BGAs is that the connection is made under the BGA chip. This feature, along with the abundance of solder balls, makes it difficult to sell and export and increases the chances of making solder bridges. The location also makes the BGA chip solder joints very difficult to inspect. The X-ray makes the screening process more straightforward by looking at the device to see the lower limbs, quickly identifying the bridges.

With enhancement and the ability to change the viewing angle, x-ray machines can diagnose these problems and more. Even better, all of these problems can be identified during a single test because, unlike medical imaging, operators do not have to worry about radiation exposure during operation and can use the equipment for as long as they need.

Our X-Ray Testing Skills and Services:

Testing is an essential step in bringing a product to market. A thorough inspection can prevent costly failures and memory and save the prestige of your business. For this reason, it is essential to work with a PCB manufacturer who can provide quality x-ray testing. MSG can help.

At EMSG, we understand the importance of excellent quality control. We are a full-service provider of testing and testing solutions with 20,000 square feet and 4,000 square foot office and engineering facilities. Our test site includes an x-ray test station with an x-ray source with digital controls, image identifiers, and an X-Y table for adjustment. Regardless of your industry, EMSG can provide you with quality PCB testing that meets your industry standards.

By hqt001