During PCB manufacturing and assembly, there’s a high chance of manufacturing defects. Some defects are visible by naked eyes, while some require special inspection techniques, where PCBA x-ray inspection is one such technique. In this article, you’ll revolve around PCBA x-ray inspection and all the important details related to x-ray inspection.
Table of Contents
- What’s PCBA X-ray inspection?
- What are the advantages of PCBA X-ray inspection?
- What are the types of PCBA X-ray inspection?
- What are the applications of X-ray Inspection in PCBA?
- How PCB X-ray inspection work?
- 2D and 3D X-ray Inspection
- X-ray Inspection of Solder Joints
- X-ray inspection of components
- What are the common defects that PCBA x-ray inspection can detect?
- How to select the right inspection methods for PCBA?
- Conclusion
What’s PCBA X-ray inspection?
When inspecting a PCB for any defects during the manufacturing process, x-ray inspection can be used. It’s a technique that allows you to get a deeper and better look at your PCB to find defects the size of microorganisms. PCBA X-ray inspection intends to keep the PCB assembly board safe while giving all the insights of any possible manufacturing defects.
Thus, it allows manufacturers to take corrective actions as needed. Many people also call PCBA X-ray inspection as PCBA X-ray testing. This type of testing can be performed in different stages, so as to maintain quality assurance of the PCBA board.
Also read: PCB VS PCBA – What’s the difference
What are the advantages of PCBA X-ray inspection?
- Enables Non-destructive Testing
X-ray won’t harm your PCB, so you can stay worry-free about your PCB/PCBA getting damaged during inspection. Moreover, none of the components would get harmed during PCBA x-ray inspection. - Helps Verify Proper Component Placement
It’s quite possible that the components on a PCBA might look properly placed but there might be a slight misalignment. To find any improper placement and overcome this issue, PCBA x-ray inspection comes into action. - Gives An Insight Into The PCB
Viewing your PCB with your naked eyes won’t reveal many defects. But PCBA x-ray inspection can give you a deep insight without the need for a microscope or any magnifying device. - Helps Achieve Quality Assurance
If you can find out and correct any issues and defects in your PCBs before selling it to the clients, you’re assuring quality in your products. Your efforts in quality assurance will play a key role in boosting your business in the long-term.
What are the types of PCBA X-ray inspection?
- 2D X-ray Inspection
In 2D inspection, the inspector takes a 2D image and represents all the components, solder joints, layers, etc., in a top-down view. This’ll help manufacturers verify solder joints, component placement, and identify solder bridges (if any). - 3D X-ray Inspection
The inspector will take a 3D image of the PCBA and will show you all the layers and internal structure. Several images from several angles might be needed to recreate a 3D image of your PCB. - Microfocus X-ray Inspection
The microfocus x-ray inspection clicks images in a small section that helps capture a high-resolution image of a small spot. Rather than taking pictures of the entire PCB/PCBA, a small area or a region is inspected at a time. - Automated X-ray Inspection
In the automated inspection, a robotic inspector is deployed for the PCBA inspection. Some inspection machines might be involved along with the robot for better automation testing. - Manual X-ray Inspection
When going with the manual x-ray inspection, a human inspector is assigned to the project. He/she will manually place the PCB/PCBA under the x-ray machine and will perform all the test functions.
What are the applications of X-ray Inspection in PCBA?
1.Inspecting BGA and QFN: Quad Flat No-lead and Ball Grid Array are the two components on a PCB. They have solder joints under them, which can only be inspected through x-ray testing.
Also read: QFN package – a step-by-step guide for beginners
2.Wire Bond Inspection: Semiconductor devices have wire bonding connections and x-ray testing is used to check the integrity of them.
3.Inspection of Solder Joints: It’s not always guaranteed to have 100% perfect solder joints during PCB making. Therefore, PCBA x-ray inspection serves as an economical way to ensure that no solder joints are loose or damaged.
4.Analyzing Internal Structure: PCBA x-ray inspection is a very great option to check the internal structure and condition of a PCB without damaging it, which isn’t possible with naked eyes or a microscope.
5.Quality Assurance & Customer Satisfaction: PCB makers, who thrive on high-quality PCB delivery always take help of PCBA x-ray inspection to make sure that they put a smile on their clients’ faces every time they deliver PCBs to them.
How PCB X-ray inspection work?
- Setting Things Up
- Engineers choose an x-ray inspection method and set up tools needed for the process.
- The PCB is placed under the x-ray machine.
- Generating X-rays
- The x-ray machine emits high-speed electrons to the metal target and when these electrons are reflected by the target, x-rays are produced.
- If you want to get a deeper insight into the PCB, then the x-ray machine needs to be adjusted a little bit. Then it’ll allow x-rays to penetrate in the surface and reveal the insights of the PCB.
- Different materials on the PCB will absorb x-rays in different amounts. The amount of x-ray absorption is later helpful for the engineers during analysis.
2D and 3D X-ray Inspection
When it comes to inspecting printed circuit boards (PCBs), both 2D and 3D X-ray inspection methods are valuable tools, each with its own strengths and applications.
2D X-ray Inspection: Think of 2D X-ray inspection as taking a single snapshot of a PCB. This technique captures a flat, two-dimensional image that reveals the internal features and potential defects of the board. It’s great for spotting issues like misaligned components, solder joint defects, or foreign objects that might be causing problems. However, since it provides only one perspective, it can sometimes miss problems that are hidden from view in the single image.
3D X-ray Inspection: Now, 3D X-ray inspection takes things a step further. Instead of just one flat image, this method uses multiple X-ray images taken from different angles to create a three-dimensional view of the PCB. Imagine it as peeling back layers of the board to see all its internal features from every angle. This detailed view helps in identifying issues that 2D X-rays might miss, such as complex soldering defects or internal structural problems. It’s particularly useful for more intricate PCBs where components are densely packed or where you need to ensure the quality of internal layers.
X-ray Inspection of Solder Joints
When inspecting solder joints on a PCB (Printed Circuit Board), X-ray inspection is a powerful technique that offers a detailed look into the quality and integrity of these critical connections.
Why X-ray Inspection?: Solder joints are crucial because they connect electronic components to the PCB. Any defects in these joints can lead to circuit failures or unreliable performance. X-ray inspection allows you to see beneath the surface of the board, which is especially important because many solder joints are hidden from view once the components are placed on the board.
How It Works: The X-ray machine sends X-rays through the PCB, capturing images that reveal the internal structure of the solder joints. This method is capable of detecting various issues such as cold solder joints, which occur when solder fails to melt completely, or solder bridges, where excess solder creates unwanted connections between components.
Benefits: One major advantage of X-ray inspection is its ability to see inside the solder joints without dismantling or physically disturbing the board. It can highlight problems such as voids (air pockets within the solder) and insufficient solder coverage, which might not be visible through traditional optical methods. This non-destructive approach helps ensure that solder joints are properly made and that the PCB will perform reliably in its intended application.
Application: X-ray inspection is particularly valuable for complex PCBs with dense component placements, where manual inspection is impractical. It’s often used during quality control and in production environments to catch defects early and ensure that the final product meets high standards of reliability and performance.
In essence, X-ray inspection of solder joints is like having a detailed, non-intrusive look inside the heart of the PCB, ensuring that all the critical connections are solid and free from hidden issues.
X-ray inspection of components
X-ray inspection of components on a PCB (Printed Circuit Board) is a technique that helps ensure the quality and reliability of electronic assemblies by allowing a detailed view of the internal structures of components that are otherwise hidden from view.
What It Reveals: When we talk about X-ray inspection of components, we’re looking at how this technology can help identify issues within electronic parts mounted on a PCB. For instance, it can reveal problems like internal defects in components, misalignment, or incorrect placement. This is crucial for detecting issues that might not be visible from the outside, such as internal wire bonds, die attach quality, or even issues with the component’s internal circuitry.
How It Works: X-ray inspection works by passing X-rays through the PCB and its components, capturing images that show what’s inside. These images help identify problems such as poor soldering, hidden cracks, or misconnected wires. For example, it can show whether the solder joints connecting a component to the PCB are properly formed or if there are any hidden defects within the component itself.
Benefits: This technique is especially useful for high-density PCBs with tightly packed components, where traditional inspection methods might not be effective. It’s non-destructive, meaning the board doesn’t need to be taken apart or physically altered to inspect the components. This makes it ideal for quality control and reliability testing, helping catch issues before the PCB goes into production or reaches the customer.
Application: X-ray inspection is commonly used in industries like electronics manufacturing and repair, especially when dealing with complex or critical components. It helps ensure that the components will function correctly and reliably by providing a clear, detailed view of their internal structures.
In summary, X-ray inspection of components on a PCB offers an invaluable insight into the hidden aspects of electronic parts, helping to identify potential problems that could affect performance and ensuring the overall quality of the assembled board.
What are the common defects that PCBA x-ray inspection can detect?
1.Improper or Insufficient Solder: Sometimes there can be a lack of solder on a joint that can cause a short circuit and/or overheating in the PCB/PCBA.
2.Cold Solder: Even if you’ve applied enough solder on a joint, it’s possible that the joint has not bonded nice and tight, which is termed as “cold solder”.
Also read: Cold solder joints – Unraveling the hazards, causes, detection, repair, and prevention
3.Solder Bridging: Solder bridging is an annoying defect that results in an unwanted connection between two pins and/or components on a PCBA.
4.Tombstoning: Tombstoning is a situation when a component on your PCBA gets lifted from one side, resulting in a misalignment. (Under the right circumstances, the component’s base is parallel to the PCB, while in tombstoning, the gap between the component and PCB is different at different points). X-ray inspection can help detect that.
5.Void in Solder Joints: Any air bubbles or gaps in the solder joint will create a weak bond and will impact the overall mechanical strength of the PCB. This can lead to overheating and/or short circuit.
Also read: How to deal with air bubbles in solder joints during PCBA process?
How to select the right inspection methods for PCBA?
There are several types of PCBA x-ray inspection, but which one suits you? Let’s see!
- Learn About Inspection Types First
First you must learn and get an idea of all the types of inspection techniques trending in the market. That’ll help you figure out which one suits you the most. - Consider Your PCB’s Complexity
If your PCB is simple, then 2D testing would be enough. But if your PCB has fine components and the number of components, joints, and traces is high, then go for automated or microfocus testing. - Consider Your Production Volume
If you have bulk PCB order, then manual testing would increase the delivery time. Therefore, go for automated testing. If the production is low, then manual testing would be of great help.
Conclusion
After learning about the basics and insights into PCBA x-ray inspection, you might be wondering that it’s a lot of hectic and hassle. Therefore, go with IBE Electronics that’ll choose the best PCBA x-ray inspection technique and will conduct the testing in a professional manner, without requiring your effort of involvement.
