The printed circuit board (PCB) designs are evolved over the years. Nowadays, compact and highly dense circuit board designs are gaining popularity. These denser packages, including flip chips, QFNs, BGAs, and CSPs, feature several tiny components that are not visible to naked eyes. Owing to their size and dense designs, any damage or failure in these components goes unnoticed. If allowed to operate for a long a time, they may damage the electronic equipment. Thus, to avoid this, the electronic manufacturers employ X-ray inspection technique. As the name suggests, this refers to an in-depth examination of the printed circuit board using short-wavelength X-rays. These rays can penetrate solder joints and inner packaging. This post discusses the importance of x-ray testing in printed circuit boards, its working procedure, and its benefits for your PCB applications.
Types of X-ray Testing
X-ray testing systems for CSPs, BGAs, QFNs, and flip chips are distinguished into two types:
- 2D X-ray Systems: 2D x-ray systems offer 2D images of the components on the printed circuit boards. 2D x-ray testing is ideal for simple and less complex designs. Clear pictures of the boards help identify errors and rectify the same before it escalates. 2D X-ray systems work similar to the ones used for checking bone fractures. These systems can be operated online or offline.
- 3D X-ray Testing: 3D x-ray testing is an advanced technique of PCB inspection. This testing is suitable for highly complex designs that may comprise several errors. 3D x-ray testing produces the images of cross-sections on the PCB by rebuilding 2D images.
Working of X-ray Testing Discussed
Generally, 2D or 3D x-ray devices are used for performing PCB testing. All x-ray inspection devices feature three basic features:
- Detector: A detector collects photons from X-ray and converts them into an image.
- X-ray Tube: X-ray tube is also known as a roentgen tube, which is a vacuum tube used to generate x-ray photons.
- X-ray Platform: This is where the PCB to be inspected is kept. X-ray platform rotates the object in different directions for an effective inspection from different angles.
All these features work together to perform x-ray testing on printed circuit boards. Firstly, a printed circuit board is placed on the x-ray platform. Then x-ray imaging starts working by using x-ray photons generated by the X-ray tube. Depending on the atomic mass and complexity, the photons pass through the machine generating an image of the printed circuit board. If the PCB is lightweight, it looks more transparent; however, if it is heavier and contains several components, then the appearance of metals becomes clearer because heavy material absorbs a good number of x-ray photons.
Benefits of X-ray Testing in Printed Circuit Boards
Although there are many different testing methods for PCB inspection, x-ray testing is the most effective. X-ray testing in printed circuit boards is popular across the due to the following advantages offered by them:
- Inspects Minute Errors in PCBs: Solder voids, broken solder bridges, pinhole fills, and wrong component placement are a few manufacturing errors, which experts tend to miss during visual inspections. X-ray testing inspects these errors and more minute errors effectively and allow PCB manufacturers to perform rectification.
- Cost-Effective Process: X-ray testing equipment is expensive, however, it is cost-effective when it comes to ensuring a defect-free printed circuit board.
- Eliminates Downtime: Using x-ray testing helps identify complex errors early, which eliminates further downtime.
- Pin-hole Fills: This is a common issue seen in PCB boards. 2D and 3D x-ray machines examine this error in-depth, and then the pin-holes are filled according to their measurements, eradicating future failure.
X-ray testing in printed circuit boards is performed to assure high-quality products. Although many may argue that X-ray testing requires no special skills, it is not true. The X-ray testing will produce effective results, only when the testing is performed by experts. If you are looking for a trusted PCB assembly service that employs X-ray testing across all phases of manufacturing, then you can consider Accelerated Assemblies Inc. The company has built a list of happy and satisfied clients across military, aerospace, energy, and other industries. You can get in touch with the experts at the company to discuss your requirements and their X-ray testing capabilities.
